Excel VBA call function with variable name - excel

Question

I'm trying to call a function with a variable name that is generated at run time based upon a combo box value. This is straightforward in most languages but I can't seem to figure it out in Excel VBA, I suspect this is because I don't really understand how the compiler works. I've found several posts that are close but don't quite seem to do the trick. The code below is wrong but should give an idea of what I want.
Thanks
Sub main()
'run formatting macros for each institution on format button click
Dim fn As String
Dim x As Boolean
'create format function name from CB value
fn = "format_" & CBinst.Value
'run function that returns bool
x = Eval(fn)
...
End Sub

Answer 1

CallByName is what you'll need to accomplish the task.
example:
Code in Sheet1
Option Explicit
Public Function Sum(ByVal x As Integer, ByVal y As Integer) As Long
Sum = x + y
End Function
Code is Module1 (bas module)
Option Explicit
Sub testSum()
Dim methodToCall As String
methodToCall = "Sum"
MsgBox CallByName(Sheet1, methodToCall, VbMethod, 1, 2)
End Sub
Running the method testSum calls the method Sum using the name of the method given in a string variable, passing 2 parameters (1 and 2). The return value of the call to function is returned as output of CallByName.

Answer 2

You should write a function that accepts the CB value as a parameter and then uses a select case to call the appropriate formatting function.
Something similar to this
Function SelectFormatting(Name as String) As Boolean
Select Case CBinst.Value
Case "Text1":
SelectFormatting = Text1FormattingFunction()
Case "Text2":
.
.
.
End Select
End Function

Answer 3

The above will work but not with a large number of names
Use Application.Run(MacroName, Parameters)
You have to may sure that there is a macro but it is better than the above as there is no select statement.

Answer 4

With respect to my answer above you might also find this useful to check whether the macro exists
'=================================================================================
'- CHECK IF A MODULE & SUBROUTINE EXISTS
'- VBA constant : vbext_pk_Proc = All procedures other than property procedures.
'- An error is generated if the Module or Sub() does not exist - so we trap them.
'---------------------------------------------------------------------------------
'- VB Editor : Tools/References - add reference TO ......
'- .... "Microsoft Visual Basic For Applications Extensibility"
'----------------------------------------------------------------------------------
'- Brian Baulsom October 2007
'==================================================================================
Sub MacroExists()
Dim MyModule As Object
Dim MyModuleName As String
Dim MySub As String
Dim MyLine As Long
'---------------------------------------------------------------------------
'- test data
MyModuleName = "TestModule"
MySub = "Number2"
'----------------------------------------------------------------------------
On Error Resume Next
'- MODULE
Set MyModule = ActiveWorkbook.VBProject.vbComponents(MyModuleName).CodeModule
If Err.Number <> 0 Then
MsgBox ("Module : " & MyModuleName & vbCr & "does not exist.")
Exit Sub
End If
'-----------------------------------------------------------------------------
'- SUBROUTINE
'- find first line of subroutine (or error)
MyLine = MyModule.ProcStartLine(MySub, vbext_pk_Proc)
If Err.Number <> 0 Then
MsgBox ("Module exists : " & MyModuleName & vbCr _
& "Sub " & MySub & "( ) : does not exist.")
Else
MsgBox ("Module : " & MyModuleName & vbCr _
& "Subroutine : " & MySub & vbCr _
& "Line Number : " & MyLine)
End If
End Sub
'-----------------------------------------------------------------------------------