Convert selection to Leading zero format - excel

Question

I am trying to build a simple macro that converts a selected range with numeric values to a "0000" format (e.g. 50,75,888, 1000 would be 0050,0075, 0888, 1000) i.e. it picks up each value in each cell and and returns a string value back to the sheet which can then be manipulated in Excel
Almost there (I think..) I just need help with the the $format function
Sub LeadingZero()
Dim RngSelected As Range
Dim R As String
Dim RCell As Range
Dim Rrng As Range
Dim RevNum As Long
On Error Resume Next
Set RngSelected = Application.InputBox("Please select a range of cells you want to convert to 0000 format", _
"SelectRng", Selection.Address, , , , , 8)
R = RngSelected.Address
Set Rrng = Range(R)
For Each RCell In Rrng.Cells
RCell.Value = Format$(RCell, "0000") 'this is the line I want to work!
'RCell.Value2 = Format$(RCell, "0000") doesn't seem to work either
Next RCell
End Sub
Thanks

Answer 1

Did you specifically want to do it with formatting? If you actually want to convert the value (useful for lookup and the like) then this function will do what you want.
Function FourDigitValues(InputString As String)
Dim X As Long, MyArr As Variant
MyArr = Split(InputString, ",")
For X = LBound(MyArr) To UBound(MyArr)
MyArr(X) = Right("0000" & MyArr(X), 4)
Next
FourDigitValues = Join(MyArr, ",")
End Function

Answer 2

Sub LeadingZero()
Dim RngSelected As Range
Dim R As String
Dim RCell As Range
Dim Rrng As Range
Dim RevNum As Long
On Error Resume Next
Set RngSelected = Application.InputBox("Please select a range of cells you want to convert to 0000 format", _
"SelectRng", Selection.Address, , , , , 8)
R = RngSelected.Address
Set Rrng = Range(R)
For Each RCell In Rrng.Cells
RCell.NumberFormat = "000#"
Next RCell
End Sub

Answer 3

Thanks to Assaf and Dan Donoghue:
Sub LeadingZero2()
'Takes a range with numbers between 1 and 9999 and changes them to text string with "0000" format
Dim RngSelected As Range
Dim RCell As Range
Dim Rrng As Range
On Error Resume Next
Set RngSelected = Application.InputBox("Please select a range of cells you want to convert to 0000 format", _
"SelectRng", Selection.Address, , , , , 8)
Set Rrng = Range(RngSelected.Address)
For Each RCell In Rrng.Cells
RCell.NumberFormat = "#"
RCell = CStr(Array("000", "00", "0")(Len(RCell) - 1) & RCell)
Next RCell
End Sub