Question

I have a method to execute a Distinct Result from a Table Column on a Worksheet.

The result of the Method will go into a Data-Validation listbox in a cell. I have two needs right now that require me to "dummy mitigate" the method’s use, by limiting the number of columns passed to the method by one. This part i can get done, what i would like to do is have it so that if there are multiple columns in the Range, then it "pukes" on the user, stating that an illegal function call was made from "Worksheet"."Cell" and to alert the IT Support to resolve the problem.

Getting the Worksheet is great and the easy part. Its more of getting the reference to the Calling Cell without explicitely forcing the IT Support to pass the Cell as a value to the method.

Any ideas on how to extract the Calling Cell?

Ultimately this method will be used across several worksheets to perform the same logic with different ranges being passed to it.

Edited 2012-09-24 10:30am CST

Here is my implementation so far, havent utilized the Application.Caller method into it.

Function UniqueValues(ws As Worksheet, col As String) As Variant

   Dim rng As Range: Set rng = ws.Range(col)
   Dim dict As New Scripting.Dictionary
   
   If Not (rng Is Nothing) Then
      Dim cell As Range, val As String
      
      For Each cell In rng.Cells
         val = CStr(cell.Value)
         
         If Not dict.Exists(val) Then
            dict.Add val, val
         End If
         
      Next cell
   End If
      
   'Return value
   UniqueValues = dict.Items
End Function

This method is already being used in code-behind logic. I will be copying this logic and making it apart of the Application.Volatile segment for the Excel Workbook i am working on. Will be similar but not the same.

Here is the current design, not much but what i am workgin with atm.

Function DistinctValues(rng As Range)
Application.Volatile True
    If rng.Columns.Count > 1 Then
        Err.Raise -1542376, rng.Worksheet.name, "An invalid function call was made!"
    End If
    
    
End Function

Answer 1

Application.Caller returns the cell that called a function. See this MSDN definition.