Daily Dose of Excel

Using a Class Property to do more than just Assign or Query a Value

Tushar Mehta — Fri, 09 May 2008 04:03:35 +0000

The purpose of this article is to introduce various capabilities of a class property. It is not meant to serve as an introduction to classes and objects. See the references section for introductory pages.

The typical use of a Class Property is to assign a value or to query its value as in the example below that defines the radius of a circle. This code would go in a class module named clsCircle.

Option Explicit
Dim LclRadius As Double
Property Get Radius() As Double
Radius = LclRadius
End Property
Property Let Radius(uRadius As Double)
LclRadius = uRadius
End Property

Here are three things to consider. First, there are two different procedures, one to query the value and another to assign it. Second, there’s no requirement that there be only one statement in the Get or the Let procedure. In fact, there could be just about any number of statements in either procedure. Third, there’s no rule that both the Get and the Let procedures be present. These three together mean there's a lot more one can do beyond the basic use of a property. In this document we will explore some of the possibilities. There is one critical weakness in how properties work and we will explore a workaround towards the end of this document.

Validating a property value

The first improvement is to validate the value of a property. In the case of a circle, the radius cannot be negative. So, we can enhance the code to ensure that it is not.

Property Let Radius(uRadius As Double)
If uRadius>= 0 Then LclRadius = uRadius _
Else MsgBox "Radius cannot be assigned a negative value"
End Property

Creating a Write-Once-Read-Many attribute

We can modify the above code to allow the Radius property to be assigned a value only once.

Dim LclRadius As Double, RadiusAssigned As Boolean
Property Get Radius() As Double
Radius = LclRadius
End Property
Property Let Radius(uRadius As Double)
If RadiusAssigned Then
MsgBox "Radius, a 'write-once' attribute, already has a value"
Exit Property
End If
If uRadius>= 0 Then
LclRadius = uRadius
RadiusAssigned = True
Else
MsgBox "Radius cannot be assigned a negative value"
End If
End Property

Verify that a Property has been initialized

We can use the same concept as above to verify that a property has been initialized. Thus, the property value is returned only after it has been initialized.

Property Get Radius() As Double
If RadiusAssigned Then Radius = LclRadius _
Else MsgBox "Radius property is uninitialized"
End Property

A “Virtual” Property

A property doesn’t have to have a variable associated with it. The Radius property has a private LclRadius variable that holds its value. But that is not strictly necessary. Consider a circle's Diameter property. Since it is simply twice the radius there is no need for a separate variable to contain the diameter.

Property Get Diameter() As Double
Diameter = Radius * 2
End Property
Property Let Diameter(uDiameter As Double)
Radius = uDiameter / 2
End Property

Using Properties inside the Class Module

The above example also illustrates another useful point. Even though the variable LclRadius is available to all the procedures of the class one can always use the actual property itself. In fact, unless there is a compelling reason not to, one should always use the property since this has the benefit that any additional code for the property (such as the validation of the radius) will be correctly executed.

A Public vs. a Private Property

There may a valid reason for creating a property such that it is available to other members of the class but not to a client. This is accomplished by declaring the corresponding Get or Let procedure private. Consider the Diameter property from above. Clearly, it makes good sense for the client to know the diameter of the circle. So, the Get procedure should be public (the default). Also suppose we decide that the client cannot change the diameter (all changes should be through the Radius property). At the same time, we decide that procedures inside the class itself should be allowed to change the Diameter property. We accomplish this by making the Let procedure private as in:

Property Get Diameter() As Double
Diameter = Radius * 2
End Property
Private Property Let Diameter(uDiameter As Double)
Radius = uDiameter / 2
End Property

Now, code within the class can set the Diameter value with something like:

Diameter = 2

However, a client would be unable to do something like the below since it would result in a compile time error “Method or Data Member not found”

aCircle.Diameter = 2

Referring to an instance of the class (the Me object)

The Me keyword is the way code inside the class module can refer to the instance of the object created from the class. One could call it a “self reference,” I suppose. Me is the equivalent of a client referring to a variable of the class. VBE’s Intellisense capability will show the same properties and methods that a client would be able to use.

The use of Me is relevant in the context of a private property since a procedure in the class module can refer to a private property such as Diameter above. However, assigning a value to the Diameter of the Me object would fail since Diameter is publicly read-only.

Read-only Property

Since the Get and Let property procedures are separate entities, one can always exclude one (or the other). To implement a read-only property, simply exclude the Let procedure. In the case of the circle class, once the client specifies the radius, other properties such as the area or the perimeter are easy to calculate. However, if we assume that the client cannot specify the area (or perimeter) directly, we can create read-only properties with

Property Get Area() As Double
Area = Application.WorksheetFunction.Pi() * Radius ^ 2
End Property

Property Get Perimeter() As Double
Perimeter = 2 * Application.WorksheetFunction.Pi() * Radius
End Property

Similarly, one can implement a write-only property by creating the Let procedure but excluding the corresponding Get procedure.

Property with an argument

Just like a subroutine or a function can have one or more arguments passed to it, so can a property. Suppose we want to provide a property that returns the length of the arc corresponding to a specified angle. The length of the arc is calculated as the perimeter / (2*Pi) * angle of the arc, which is also the same as radius * angle of the arc. So, we would get the property

Property Get ArcLen(ArcAngleInRadians As Double) As Double
ArcLen = Perimeter * ArcAngleInRadians _
/ (2 * Application.WorksheetFunction.Pi())
'The above illustrates how one property can use another property _
to return a calculated value. Of course, the length of an arc _
is also the simpler _
ArcLen = Radius * ArcAngleInRadians
End Property

Similarly, a Let procedure can also have an argument list. In the case of a property where the Get procedure has zero arguments, the corresponding Let procedure already has 1 argument, the value of the Let assignment. Similarly, when the Get procedure has an argument list, the corresponding Let procedure has 1 more argument than the Get procedure. The value of the Let statement is the last argument. So, if we were to allow the client to specify the radius of a circle through the ArcLen property – keeping in mind that while it helps demonstrate this capability it is not really a good idea for a ‘production’ system – we might have something like:

Property Let ArcLen(ArcAngleInRadians As Double, uArcLen As Double)
Radius = uArcLen / ArcAngleInRadians
End Property

Raising an Error

Just as we can raise an error in any procedure in our code modules, one can also raise an error in a class module. Suppose we decide to replace our Radius property’s Get procedure so that it raises an error if Radius is uninitialized.

Property Get Radius() As Double
If RadiusAssigned Then
Radius = LclRadius
Else
Err.Raise vbObjectError + 513, "clsCircle.Radius", _
"clsCircle.Radius: Radius property is uninitialized"
End If
End Property

Now, if we were to query the value of the Radius property before assigning a value to it, we would get a runtime error.

Sample Use of the circle’s properties

In a standard module, enter the code below and then execute it. It creates a circle of radius 1 and then displays its diameter, area, perimeter, and the length of the arc corresponding to 1/4th the circle.

Difference between Set and Let property procedures

Suppose we have another class, clsPoint, that contains 2 properties, the X and Y coordinates of the point.

Option Explicit

Dim LclX As Double, LclY As Double

Property Get X() As Double: X = LclX: End Property
Property Let X(uX As Double): LclX = uX: End Property

Property Get Y() As Double: Y = LclY: End Property
Property Let Y(uY As Double): LclY = uY: End Property

Now, in our clsCircle class, we could specify the center of our circle as:

Dim LclCenter As clsPoint

Property Get Center() As clsPoint
Set Center = LclCenter
End Property
Property Set Center(uCenter As clsPoint)
Set LclCenter = uCenter
End Property

Note that the Get procedure can Set the property. However, if we used a Let procedure and tried to Set the module variable, it would not work. Try it. Instead, one must use a Set procedure as in the above example.

We can now extend the testCircle subroutine (it’s in the standard module).

Option Explicit

Sub testCircle()
Dim aCircle As clsCircle
Set aCircle = New clsCircle

With aCircle
.Radius = 1
MsgBox "Diameter=" & .Diameter & ", Area=" & .Area _
& ", Perimeter=" & .Perimeter _
& ", ArcLen(Pi()/2)=" _
& aCircle.ArcLen(Application.WorksheetFunction.Pi() / 2)
End With

Dim myCenter As clsPoint
Set myCenter = New clsPoint
With myCenter
.X = 1
.Y = 2
End With
With aCircle
Set .Center = myCenter
MsgBox .Center.X & ", " & .Center.Y
End With
End Sub

Creating private “property variables”

One of the biggest weaknesses in the current implementation of a class is that any variable associated with a property must be declared at the module level. This makes the variable visible to and, worse modifiable by, any code anywhere in the module. Essentially, the variable is global to the entire module.

One generic way to make a variable persistent but not global is to declare it as static inside a procedure. That, of course, does not work with a Property since typically there are two procedures associated with a property (a Get and a Let or a Get and a Set). But, what if our property procedures called a common private procedure? Then, we could declare our local variables in this common procedure.

Create a function that declares the variable(s) associated with a property as static within its own scope. Now, the only way to access the variable is through the function – and the function can contain all the code required to assign or query a property value.

Private Function myCenter(GetVal As Boolean, _
Optional uCenter As clsPoint) As clsPoint
Static LclCenter As clsPoint
If GetVal Then Set myCenter = LclCenter _
Else Set LclCenter = uCenter
End Function
Property Get Center() As clsPoint
Set Center = myCenter(True)
End Property
Property Set Center(uCenter As clsPoint)
myCenter False, uCenter
End Property

The variable LclCenter above is private to myCenter. No procedure in the module can directly access LclCenter. All access has to be through myCenter; we have cut off unrestricted access to the variable.

One can verify the above works by simply running the testCircle code (without making any changes to it). You will get the same result.

I had hoped that with the .Net declaration of a property one would be able to declare variables local to it but unfortunately it remains impossible. The result of the below is a syntax error on the dim X... statement indicating the declaration is not allowed in the Property.

Private Class Class1
Public Property aProp()
dim X as boolean
Get
End Get
Set(ByVal value)
End Set
End Property
End Class

Summary

There’s a lot one can do with a class property beyond just associating it with a variable. The list includes, but is not limited to, introducing data validation as well as implement write-once or read-only (or write-only) properties. One can also restrict the scope of variables associated with a property.

This document shared some ideas on the subject. For those wondering, yes, I can think of some possibilities that were not discussed here. Of course, I am sure there are even more possibilities that I haven’t thought of.

References

There is much information on the subject of classes and objects. Just search Google. Two introductory topics I found -- and I don't know how the compare with other information on the subject -- are Dick Kusleika's blog post at http://www.dailydoseofexcel.com/archives/2004/09/28/classes-creating-custom-objects/ and Chip Pearson's introduction to the subject at http://www.cpearson.com/excel/Classes.aspx Chip addresses a couple of the issues addressed above as well as topics I opted to exclude from this article.

Double Clicking Through a List

Dick Kusleika — Wed, 07 May 2008 04:00:27 +0000

I have a cell with data validation. It's set as an in-cell dropdown list and contains two items: Yes and No. I want to make it so that I can double click on that cell to toggle between yes and no. But wait, that's not good enough. What about longer lists? Yes, I want something that will iterate through all the items on a data validation list by double clicking. Dare I dream.

Here's my first go at it. I figure it's going to need some work, like what happens when the user double clicks on something that's not a range, but it's a start. I've basically handled two types of lists: the kind where you hard code values separated by commas (international issue here?), and the the range reference. Oh, and I need to test named ranges, but I think they'll work.

Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)

Dim dv As Validation
Dim sDv1 As String
Dim vaList As Variant
Dim i As Long
Dim vOldValue As Variant

On Error Resume Next
Set dv = Target.Validation
sDv1 = dv.Formula1
On Error GoTo 0

If Len(sDv1)> 0 Then 'only if the cell has dv
If dv.Type = xlValidateList Then
Cancel = True 'don't do the default action
vOldValue = Target.Value
vaList = GetValidList(dv.Formula1) 'return single dim array
For i = LBound(vaList) To UBound(vaList)
If vaList(i) = Target.Value Then
If i = UBound(vaList) Then
Target.Value = vaList(LBound(vaList))
Else
Target.Value = vaList(i + 1)
End If
Exit For
End If
Next i
If Target.Value = vOldValue Then 'if cell was blank
Target.Value = vaList(LBound(vaList)) 'go to first item
End If
End If
End If

End Sub

Private Function GetValidList(sForm As String) As Variant

Dim vArr As Variant
Dim vaReturn As Variant
Dim i As Long
Dim bIsRange As Boolean

On Error Resume Next
vArr = Evaluate(sForm) 'for range reference
On Error GoTo 0

If IsError(vArr) Then 'for csv list
vArr = Split(sForm, ",")
bIsRange = False
Else
bIsRange = True
End If

If bIsRange Then 'conver to single dim array
ReDim vaReturn(0 To UBound(vArr, 1) - 1)
For i = LBound(vArr, 1) To UBound(vArr, 1)
vaReturn(i - 1) = vArr(i, 1)
Next i
Else
vaReturn = vArr
End If

GetValidList = vaReturn

End Function

This code is in the sheet's class module (Sheet1 in my case). Test it out if you like. Let me know if you see any errors or better ways.

P.S. Why is Target.Validation always something (that is, Not Nothing) even if the cell doesn't have validation?

Efficient Looping

Dick Kusleika — Tue, 29 Apr 2008 16:53:21 +0000

In a previous post, I demonstrated how to use constants to improve your code. Then everyone started beating up my loop. The code wasn't solving a real life problem, so I just threw any old loop together. It wasn't relevant because that's not what the post was about. To fight back, I created a highly improbably backstory in the comments to make my loop look at least as efficient as everyone else's.

But no matter how crazy my story was, I couldn't subvert Peltier's comment about reading the range into an array. So I tried to see what kind of time differences we're talking about. I wrote this code:

Sub DoBoth()

Dim lStart As Long
Dim i As Long

lStart = Timer
For i = 1 To 10
FindTotals2
Next i
Debug.Print Timer - lStart
lStart = Timer
For i = 1 To 10
UseArray
Next i
Debug.Print Timer - lStart

End Sub

Sub FindTotals2()

Dim rCell As Range

Const sFIND As String = "Total"

For Each rCell In Sheet1.Columns(1).Cells
If Left$(rCell, Len(sFIND)) = sFIND Then
'Do something
End If
Next rCell

End Sub

Sub UseArray()

Dim vArr As Variant
Dim i As Long

Const sFIND As String = "Total"

vArr = Sheet1.Columns(1).Value

For i = LBound(vArr) To UBound(vArr)
If Left$(vArr(i, 1), Len(sFIND)) = sFIND Then
'Do something
End If
Next i

End Sub

And got these results:

The array is quite a bit faster. I don't think Timer is hyper-accurate, but relatively the differences are pretty clear.

Testing Strings Using Left

Dick Kusleika — Mon, 28 Apr 2008 16:44:48 +0000

The "wrong" way:

Sub FindTotals()

Dim rCell As Range

For Each rCell In Sheet1.Columns(1).Cells
If Left$(rCell, 5) = "Total" Then
'Do something
End If
Next rCell

End Sub

The "right" way:

Sub FindTotals2()

Dim rCell As Range

Const sFIND As String = "Total"

For Each rCell In Sheet1.Columns(1).Cells
If Left$(rCell, Len(sFIND)) = sFIND Then
'Do something
End If
Next rCell

End Sub

Both "right" and "wrong" are in quotes because, like many best practices, it can be a matter of taste and preference. In the second method, I can change the string in one place and I'm done. In the first, if I change the string, I also have to change the second argument of Left$().

Printing First Page of Email in Outlook

Dick Kusleika — Wed, 23 Apr 2008 16:41:28 +0000

I print out my email. No, I'm not one of the Luddites that prints out every email (or has his secretary do it) because he doesn't understand how to work his email machine. My system for organization is loosely based on Getting Things Done and its derivative 43 Folders. Everything I have to do is represented by at least one piece of paper. So don't try to convince me to quit printing my email, because it's not going to happen.

If I get an email that requires some action in the future, I need one of these pieces of paper to represent that future action. Until recently, I would print the email to serve that purpose. As you already know, email can get quite long and that means I can end up with 10 sheets of paper where I only needed one. When you deal with accountants and lawyers, it's even worse because each of their messages in the thread has a page of disclaimers. Oddly, Outlook's print dialog doesn't let you specify a page range. There are some work arounds, but none of them are suitable for me. I read all my email in plain text and I reply in plain text (HTML is for web pages, not email). Since I'm using plain text, I use Outlook's built-in email editor rather than Word.

After I printed seven pages of an email today, I decided to finally write some code. I put a button on my new email commandbar and hooked it up to this procedure:

Sub PrintOnePage()

Dim mi As MailItem
Dim sBody As String
Dim wdApp As Word.Application

Const sORIG As String = "> -----Original Message-----"

If TypeName(Application.ActiveInspector.CurrentItem) = "MailItem" Then 'only mail
'create a forward to get the header
Set mi = Application.ActiveInspector.CurrentItem.Forward
sBody = mi.Body
sBody = Mid(sBody, InStr(1, sBody, sORIG), 5000) 'Remove inserted signature
Set wdApp = New Word.Application

With wdApp.Documents.Add
.Range.Text = sBody
.PageSetup.LeftMargin = 18 '.25"
.PageSetup.RightMargin = 18
.PageSetup.TopMargin = 18
.PrintOut False, False, wdPrintFromTo, "", "1", "1"
End With

wdApp.Quit False 'don't save changes
Set wdApp = Nothing
mi.Close olDiscard 'don't save changes
Set mi = Nothing
End If

End Sub

I didn't want to automate Word to do this, but I struggled with other options to limit it to one page. I know that printing out of Outlook puts 60 lines on the first page. However, when I tried to limit the text to the first 60 vbNewLine's, it didn't quite work out. I started to think that maybe Outlook doesn't put a vbNewLine after each line, but rather after each paragraph. I'm still not sure why that didn't work. So I resigned to automate Word and use it's page range feature to limit the print out.

I limit this to MailItems although it may work on other objects. I didn't want to test it. The MailItem I work with is a forwarded copy of the original. When I forward an email it puts the header information at the top of each email in the thread, so I get some needed information on my print out. Unfortunately, it also puts my signature in there, so I have to strip that part out by starting the string at the Original Message part. And I limit the string to 5,000 because that should be more than one page and there's no need to transfer more than that.

I kept getting a type mismatch error when using Word's PrintOut method. At first I thought it was because I was omitting optional arguments, but that really shouldn't be the case when I'm early binding. I seem to remember a problem with optional arguments using late binding - specifically that you have to include all optional arguments up until the one you want to include, then none after that. But I was still getting the error. Inexplicably, Word wants Strings for page numbers. You'll notice that my page numbers are in quotes.

Finally, I close Word without saving changes and discard the forwarded copy of the email.

VBE Bookmark add-in for Office 2000-2007

Ron de Bruin — Mon, 21 Apr 2008 19:44:00 +0000

Hi all

New page on my site with a very useful add-in from Jim Rech.
http://www.rondebruin.nl/vbebookmarks.htm

VBEBookmarks.dll is a simple COM Add-in created by Jim Rech for the Microsoft Office 2000-2007 Visual
Basic Editor which lets you bookmark up to five locations in VBA projects for easy navigation among them.

Have fun

Ron de Bruin
http://www.rondebruin.nl/tips.htm

I’ve Arrived

Dick Kusleika — Mon, 14 Apr 2008 21:56:29 +0000

I'm in Seattle for the MVP Summit. This hotel is great. I just downed a whole jar of complimentary Macademia nuts and... What's this thing that looks like a menu? Damn!

I'm off to register and score some of the Rock Bottom brew. I'll be sure to have one for those of you who couldn't make it this year.

Mike Won!

Dick Kusleika — Mon, 14 Apr 2008 03:02:18 +0000

Mike from the Northeast won the 4-year anniversary contest. A copy of Dalgleish's Excel Pivot Table Recipes is soon to be rushing to his house from wherever Amazon rushes stuff. In the contest, I asked for your favorite non-Excel blogs, and here are some of them:

Office Live Small Business... - Why are Microsoft brand names a whole paragrah? Just say it already!
The Secret Diary of Steve Jobs
Sasha Frere-Jones
101-things-in-1001-days - I was going to do that once - too hard.
Pogue's Posts
Stuff White People Like - A little racism for variety.
Information Aesthetics
Hot Air
Old New Thing
Sean MacNair - Kiss over Zep? C'mon!
Experiences of an English Soldier
Gizmodo - I quit reading gadget sites for some reason. Maybe it's time to start again.
Creed Thoughts - Possibly my favorite non-Simpsons show

I haven't read many of these blogs and don't endorse them. But I casually glanced at them and will probably give them a second look.

I'm heading to Seattle tomorrow for the MVP Summit. If you read blogs by other Excel MVPs, you know we like to drink at the Rock Bottom. As is my tradition, I got a new pair of shoes right before the summit. I bought Sketchers this time because I'm trying to look younger. It must be a mid-life crisis thing. Now if I could just learn to balance on a skateboard.

Tab Groups

Dick Kusleika — Tue, 08 Apr 2008 01:59:36 +0000

Scott wishes:

G’day Dick,

My wish list would be to have the functionality to group excel tabs within a workbook. So instead of having 20+ tabs going along the bottom of the screen you could group (similar to TabScrip in VBA ) them into a common theme. Maybe group all the raw data tabs, input sheets, output reports, State summaries, Yearly reports, etc.

Now, if you have some finance VBA code that already does it……then here’s your chance to make a wish come true. 

Cheers matey.

I couldn't find a picture of TabScrip, and if he meant TabStrip, then I don't know what he's talking about. You can color your tabs to group them. You can't move the tabs to any other position except the bottom, as far as I know.

I have a few workbooks that have a lot of tabs. In those rare situations I wish for better navigation of tabs. If you right click on the VCR buttons to the left of the tabs, you can quickly select a tab. If you have more than 16 tabs, you can't see them all. Instead you get a "More Sheets" options that brings up an unsortable dialog.

First, I'd like that right click list to go all the way to the top of the screen. Don't stop at 16, stop at 30 or some other number that gives me more options. If I do need to open the dialog, I want three sort options: the order they appear in the workook; alphabetical order; and zOrder (the order in which they were last accessed). I guess that's six sorts with ascending and descending options. I don't really need this because I only have a handful of really big workbooks. But it would be handy in those cases.

What do you think about Scott's wish or tabs in general?

Copy Paste to External Application

Rob van Gelder — Sat, 05 Apr 2008 21:12:25 +0000

Sometimes I find myself copy-pasting between Excel and another application.
In this example, I have a table of three columns: First Name, Last Name, Birth Date.
My external application has 3 text boxes, one for each of those values.

I can't just copy the 3 cells from Excel and paste them to my App, because they would all end up in the first text box!
But, by running VBA SendKeys with a specially crafted string, I can send keystrokes for tabbing to the 2nd and 3rd text boxes.

I also need to activate the SendKeys procedure only when my cursor is positioned correctly, or things could get messy.

My approach is to run a macro that sits there listening for F6 before activating SendKeys.
I've also included listening for the Esc key, just in case I change my mind.

Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Long) As Integer

' Virtual-Key Codes http://msdn2.microsoft.com/en-us/library/ms645540(VS.85).aspx
Const VK_F6 = &H75
Const VK_ESC = &H1B

Sub Scanning()
Dim lngRow As Long, str As String

lngRow = Selection.row
str = Cells(lngRow, 1) & vbTab & Cells(lngRow, 2) & vbTab & _
Format(Cells(lngRow, 3), "dd-mmm-yyyy")

MsgBox "Click OK, then click the First Name box on the external application, then press F6 on the keyboard"
WaitAndSend str, VK_F6, VK_ESC
End Sub

Sub WaitAndSend(SendString As String, ExecuteKey As Long, CancelKey As Long)
Do
DoEvents
If GetAsyncKeyState(CancelKey) <> 0 Then Exit Do
If GetAsyncKeyState(ExecuteKey) <> 0 Then
SendKeys SendString, True
Exit Do
End If
Loop
End Sub

Getting the Printer Port

Dick Kusleika — Sat, 05 Apr 2008 16:13:15 +0000

Do you know how windows appends that "on Ne01" to your ActivePrinter. In the old days we had to loop through all the possible digits to find which one didn't error out. Well no more!

Holger uses the registry to find the printer port. Very clever. However, if you have back slashes in your regestry key name, the scripting shell object won't work for retrieving them. To the shell, back slashes are path separators, so it's trying to navigate down some path that doesn't exist.

To overcome that problem, you can use Registration Manipulation Classes.

If ~~your~~ you're a late binding kind of a guy, use CreateObject("RegObj.Registry") in your code. With this dll, we can loop through all of the keys in a folder, like so:

Function GetPrinterPort(sPrinterName As String) As String

Dim objReg As RegObj.Registry
Dim objRootKey As RegObj.RegKey
Dim sKey As String
Dim objVal As RegObj.RegValue
Dim sData As String
Dim vData As Variant

sKey = "\HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Devices\"
Set objReg = New RegObj.Registry
Set objRootKey = objReg.RegKeyFromString(sKey)

For Each objVal In objRootKey.Values
If objVal.Name = sPrinterName Then
sData = objVal.Value
Exit For
End If
Next objVal

If Len(sData)> 0 Then
vData = Split(sData, ",")
GetPrinterPort = vData(UBound(vData))
Else
GetPrinterPort = ""
End If

Set objReg = Nothing

End Function

I haven't tested that extensively, so use caution.

Investing in Lean

Dick Kusleika — Fri, 04 Apr 2008 02:38:00 +0000

I'm a big fan of the Toyota Production System. I was thinking that I should find a mutual fund that invests in lean companies, but I couldn't find one. I searched for "best lean companies" to see if I could get a list, and found Who Are the Best Lean Companies at leanblog.org, a blog I read every day.

I took all of the companies in the top 10 for whom I could find historical data. I compared buying one share of each of those companies to buying one "share" of the S&P500 over the same period. The lean companies outperformed the index.

D9: =RATE(C1-B1,0,-B9,C9)*365
D11: =RATE(C1-B1,0,-B11,C11)*365

Are those formulas right? I'm trying to get an annual return.

I couldn't stock-pick my way out of a paper bag (I'm looking at you Buckle; I'm looking at you Inacom), so don't take investing advice from me.

Updating Stock Quotes

Dick Kusleika — Wed, 02 Apr 2008 02:49:29 +0000

I answer about four questions a month on the newsgroups. I'm off to a roaring start in April, but I don't like my answer much. I never know just how "correct" an answer to give. So I gave an answer that I felt was appropriate for the original poster and I'll give a slightly different answer here.

The OP has an external query pulling stock quotes from Yahoo! Finance. He's using their csv download option, but just querying the csv rather than downloading it and loading it into Excel. One problem with that is that it puts all of the data in one column. If there's a built-in way to fix that, I don't know it. The other problem is that the list of companies he wants to see is variable and lives in a range of cells. I actually don't know if these are his problems, but I like to pretend.

My objectives are to create a web query to Yahoo, add a parameter that points to a range, and parse the data into multiple columns. Does that sound like fun? Well, I'm doing it anyway.

I can't create the query the old fashioned way. The web query user interface is like a browser; if you try to point to a CSV file, the browser wants to download it. So I create a web query to whatever table is on whatever page that happens to open up. Basically, I'm creating a query that I will later edit to point to where I want.

I pick any old arrow on the Dell website and create a query. I get a message that my query doesn't return any data, but I just OK past that message because I know I'll be making changes. Next I go to the VBE, and specifically the Immediate Window, to change my query.

The part you can't see says this:

wshquotes.QueryTables(1).Connection = "URL;http://quote.yahoo.com/d/quotes.csv?s=^GSPC[""EnterTicker"",""Ticker""]&f=nl1c"

If this URL isn't exactly what you want, don't worry. Alex has done all the legwork that will allow you to get whatever data you want. For me, I'm getting the name, last, and change for the S&P500 Index plus whatever else I enter. The "whatever else I enter" part is the parameter and is the name/prompt pair of strings inside the square brackets. When I Refresh the QueryTable, it asks me for a Ticker. I enter MSFT and the web query returns some data.

I have a parameter, but it doesn't point to a range, so that's next. The range B1:B10 will hold whatever ticker symbols I want and D1 will put them in the format I need for the URL.

The formula in D1 is ="+"&B1&IF(NOT(ISBLANK(B2)),"+"&B2,"")&IF(NOT(ISBLANK(B3)),"+"&B3,"")&IF(NOT(ISBLANK(B4)),"+"&B4,"") &IF(NOT(ISBLANK(B5)),"+"&B5,"")&IF(NOT(ISBLANK(B6)),"+"&B6,"")&IF(NOT(ISBLANK(B7)),"+"&B7,"")&IF(NOT(ISBLANK(B8)),"+"&B8,"") &IF(NOT(ISBLANK(B9)),"+"&B9,"")&IF(NOT(ISBLANK(B10)),"+"&B10,"")

Inspiring, huh? If a ticker exists, it puts a "+" in front of it and adds it to the list. Now I can click on the Query Parameters button on the External Data Toolbar and point to D1.

I also click on the Data Range Properties button and check the box to make the table automatically refresh.

OK, I have a parameterized web query that refreshes automatically. Unfortunately, it gives me this

Everything in one column. Yuck. Time to get fancy. I know that Text to Columns will parse the results, but I'm not going to manually do that every time the QueryTable refreshes. Fortunately, QueryTables have events. Two events, to be precise. I'll be using the AfterRefresh event. I'll bet you can guess what the other one is.

Other than out brief jaunt into the Immediate Window, we've been pretty much in Excel's UI up until now. It's time to step through the looking glass into VBA and (gasp) class modules. Open the VBE (Alt+F11) and add a class module and a module to your project. Name the class module (F4) CQTEvents and name the module MEntryPoints. In your class module, put this code:

Option Explicit

Private WithEvents mobjQTable As QueryTable

Private Sub Class_Terminate()

Set mobjQTable = Nothing

End Sub

Public Property Get QTable() As QueryTable

Set QTable = mobjQTable

End Property

Public Property Set QTable(objQTable As QueryTable)

Set mobjQTable = objQTable

End Property

Private Sub mobjQTable_AfterRefresh(ByVal Success As Boolean)

Application.DisplayAlerts = False

mobjQTable.ResultRange.TextToColumns _
Destination:=mobjQTable.ResultRange.Cells(1), _
DataType:=xlDelimited, _
TextQualifier:=xlTextQualifierDoubleQuote, _
Comma:=True

Application.DisplayAlerts = True

End Sub

Of course I never use public variables in a class because I'm a class module snob. So I have a private variable declared WithEvents that exposes the events of the QueryTable variable. Because it's a private variable, I need public get and set statements so code outside of the class can access it. Finally, I create the AfterRefresh event (using the code pane drop downs) and simply call the TextToColumns method to parse out the QueryTable results. If you try to TextToColumns into a range that already contains data, you'll get a message. I use DisplayAlerts to avoid that.

The only thing left is to tell my class which QueryTable I care about. I do that in the standard module with this code:

Option Explicit

Public clsQTEvents As CQTEvents

Sub Auto_Open()

Set clsQTEvents = New CQTEvents

Set clsQTEvents.QTable = wshQuotes.QueryTables(1)

End Sub

Sub Auto_Close()

Set clsQTEvents = Nothing

End Sub

That's so easy I don't even have to explain it. Run Auto_Open and wait for your QueryTable to refresh. Then go fix your typos and you're all set. And you thought class module were difficult. If you're following along at home, be sure to do this during trading hours. Having those one minute updates where nothing changes isn't too exciting.

Can You Believe

Dick Kusleika — Tue, 01 Apr 2008 03:06:34 +0000

That I started this blog four years ago. I can't. It seems more like six and a half. Here's some stats:

That's about 26 posts per month and about 8 comments per day. I'm no Nick Hodge, but hey.

As is my wont, I'll be having an anniversary give-away. I just like to give back to all the people who read, comment, and click on the advertisements. This year you get a choice between RibbonX: Customizing the Office 2007 Ribbon and Excel PivotTables Recipes. To enter

Send me an email with a link to your favorite non-Excel blog, which book you prefer, and a subject of "Four More Years".
If you use a different subject or your email doesn't contain a link or you don't pick a prize, you're out.
I must receive the email by 12:00AM Central Daylight Time, April 7th, 2008.
You must send the email from the same email account with which you registered on this site. If you're not registered, you can't win. If you used a fake email to register, just include that fake email address in your message so I can confirm you're registered.
This list of eligible entrants will be entered into an Excel spreadsheet, a random number will be entered next to his name, and the list will be sorted on the random number. Whoever is at the top, wins.
I'll probably list some of the more interesting blogs, but I won't associate them with your name, so don't be afraid to send in ParisHiltonWatch.com
One email per registered reader.
The winner will get to choose between a copy of RibbonX: Customizing the Office 2007 Ribbon or Excel PivotTables Recipes.
To be eligible, the entrant must live in a place that Amazon.com will ship to and where the shipping will be less than the cost of the book.
Any other rules that make this contest less of a burden on me or that I may choose to enact retroactively or otherwise makes the give-away legal and easy are hereby included.

Thanks for reading!

Excel and Music

Dick Kusleika — Mon, 31 Mar 2008 13:31:05 +0000

Finally, a legitimate use for Excel

Excel & Music

I get all of them except the "Milkshake" one.

Limits

Dick Kusleika — Fri, 28 Mar 2008 20:27:27 +0000

I recently ran into a problem with an application I developed over a year ago. I had pre-formatted 100 rows in a template, some just formatting, some conditional formatting. "We'll never need 100 rows", I said. One hundred ninety-six rows later and I feel like the Patent Commissioner who said everything has already been invented.

Should I have picked 1000? Should I have formatted the whole column? I wasn't trying to be stingy, I just doubled what I though was the most rows we'd ever use. What do you do?

Two popular tools updated.

jkpieterse — Fri, 28 Mar 2008 19:03:03 +0000

Hi All,

As many of you know I give away a number of tools for Excel through my site www.jkp-ads.com. Today I have updated the two most popular downloads:

Name Manager (which I created together with Charles Williams, www.decisionmodels.com):

Most important change: the unused names filter now includes objects in its search, as well as VBA code. It makes the filter much slower, but way more useful in my opinion. Also, I have added the Greek character set so Name Manager doesn't (wrongfully) think range names with Greek characters are corrupt.

So far, Name Manager has been downloaded about 50,000 times since I posted it on my site.

Flexfind

I have updated the user interface of Flexfind so (in my opinion) it is easier to use. Also, I have mimicked the find all behaviour of Excel: if you select multiple items in the found items list, Flexfind will create a (multiple) selection of areas of the found cells.

Flexfind is less popular than Name Manager, the download count is at about 23,000.

Enjoy!

Of course I am open to any comments, suggestions and -most importantly- lots of praise

Regards,
Jan Karel Pieterse
www.jkp-ads.com

External Data Worksheets

Dick Kusleika — Tue, 25 Mar 2008 18:08:12 +0000

Someone sent me an email last week suggesting I have a Wishlist category where we could discuss features we hope MS will someday incorporate into Excel. I think that's a fine idea. If you like, send me an email with your wish. If I find it sufficiently interesting, I'll post it for others to comment.

For my first wish, I'd like a sheet in my workbook dedicated to External Data. I think someone on Simon's blog suggested this in a comment once (maybe Harlan). The worksheet would be a recordset of an external data source and nothing else. Users would not be able to type anything outside the recordset or change much about the sheet. Here's the kicker: Excel would keep the sheet and the external data source in sync. When you write to a cell on the sheet, the external data would be updated. If the recordset isn't updateable, you wouldn't be able to write to the cells. If you try to put a string in a cell that's linked to an external data field designated Integer, you would get an error. Basically it would be like datasheet view in Access. Now I handle all this will class modules and ado, but it would be nice to stay within Excel's object model to accomplish the same thing. Not to mention the UI.

One prediction I made at the recent Excel Users Conference in Sydney is that Excel and Access will be one product in our lifetime (well mine anyway). Have you seen Access 2007? Do those dropdowns in datasheet view look familiar? "But Access is a database", you say. No, not really. Access is the front end to a database. In my world, Excel is usually the front end to a database. It's not that I don't like Access, there are just people who are better at it than me, so I generally avoid that kind of work. The recent datasheet view changes in Access 2007 brings that prediction one step closer. My external data worksheet wish would bring it closer still. The only question that remains is whether to call it Accel or Excess. I prefer the latter.

You can leave your own wish in a comment (or email as noted above), comment on my wish, or leave a comment with what you would name the new combination Excel/Access product.

Random Sorts

Dick Kusleika — Mon, 24 Mar 2008 02:54:54 +0000

Red wants to have a kind-of lottery for his students. He will award them prizes based on a random drawing, but wants to weight each student based on the number of assignments turned in. Normally, I would accomplish this by typing the name of each student in column A one time for every assignment he turned in. If John turned in three assignments, I'd type his name three times. In column B, I'd put a RAND() function and fill it down. Then I'd sort by column B. I'd get something that looks like this:

That's all well and good, but it's missing a few things. If I'm giving away three prizes, Sue wins them all unless I manually exclude her. But the worst part is that it happens too fast. Excel calculates so fast that it's not entertaining to calculate in front of a group (unless you're Charles Williams, of course). I wanted to come up with something that doesn't allow ties, calculates more slowly, and is generally more friendly. Here's my first stab

Behind the button, I have this code:

Public Sub DrawNext()

Dim rNames As Range, rCell As Range
Dim rLastICell As Range
Dim i As Long

FillNames

Set rLastICell = wshDraws.Range("I65536").End(xlUp).Offset(1, 0)

If rLastICell.Row> 2 Then
Set rLastICell = rLastICell.Offset(-1)

Set rNames = wshDraws.Range("I2", rLastICell)

For Each rCell In rNames.Cells
For i = 1 To 50
rCell.Offset(0, 1).Value = Rnd * 1000
Next i
Next rCell
End If

End Sub

Private Sub FillNames()

Dim rNames As Range
Dim rCell As Range, rEntry As Range
Dim i As Long, j As Long

Set rNames = wshDraws.Range("I2")
Set rEntry = wshDraws.Range("A2:A31")

wshDraws.Range("I2:J65536").ClearContents
j = 0

For Each rCell In rEntry.Cells
If Not IsEmpty(rCell.Value) Then
For i = 1 To rCell.Offset(0, 1).Value
rNames.Offset(j).Value = rCell.Value
j = j + 1
Next i
End If
Next rCell

End Sub

The user enters the information in columns A and B, up to 30 students. The code fills column I with one instance of each name for each assignment. Then for each name it fills in a random number between 0 and 999. For show, it fills each cell 50 times to make it look like it's really doing some work.

In column C, I have this array formula

=MAX((rNames=A2)*(rDraws))

and in column D, this

=IF(RANK(C2,$C$2:$C$31)>3,"",CHOOSE(RANK(C2,$C$2:$C$31),"1st Place","2nd Place","3rd Place"))

There's not a lot of error checking and far too many literals in the code, but it's a start.

Download Lotter.zip. Yes, it's 2003 format.

Excel User Conference Download

Dick Kusleika — Wed, 19 Mar 2008 01:50:35 +0000

Download Presenter Notes and Sample Files

If you didn't attend, these files will be of limited value. But there they are if you want them.

As I mentioned at the conference, I will be reformatting my laptop hard drive this weekend. My folder problem that I've been blaming on Groove, isn't Groove's fault (I think), but I'm due for a data enema anyway. I've downloaded Belarc Advisor to get a list of installed programs. I will only be installing Excel 2000, ~~2203~~2003, and 2007. I eschewed 97 a while ago and I'm going to get rid of XP too. Any other tips before I embark on this magical journey?

Software to install (* means I want to know what you use):
Office 2000
Office 2003
Office 2007
TaxACT*
CDex
Canoscan
FileZilla
VB6
Foxit Reader
Alleycode
Aptana
InstantRails
StarCaddy
JetAudio
Firefox
RealVNC*
SnagIt
PDFCreator*
Irfanview*
VBScroll

Not making the cut:
Adobe Reader
Avast antivirus (I'm going without)
Copernic Desktop (any good desktop searches out there?)
Virtual PC (maybe next beta)
Lifecam (never use it, shouldn't have bought it)
Google Earth
Google Sketchup
Street and Trips*
VS.Net (I'll have to put it on eventually)
Subverstion
TortioseSVN