VBA Powerpoint Reference a textbox with variable - vba

Question

I am attempting to write a vba loop that will detect the value of all ActiveX textboxes on the slide. However I am have trouble writing the code for the "variable" in the textbox reference. For example TextBox(i) needs to be referenced in the loop. Where i is an integer I set the value to.
Dim i as Integer
For i = 1 to 4
If IsNull(Slide1.Shapes.("TextBox" & i).Value) = True
Then (Slide1.Shapes.("TextBox" & i).Value) = 0
Else: ...
Next i
However this script doesn't work and I have been unable to locate a source for how to properly code this variable portion of script. There has been some talk of using Me.Controls however I am not creating a form. Would anyone be willing to share what the error is here in my script?

Answer 1

This will put the value of i into TextBox i. Should get you started, I think.
Sub Example()
Dim oSh As Shape
Dim i As Integer
On Error Resume Next
For i = 1 To 4
Set oSh = ActivePresentation.Slides(1).Shapes("TextBox" & CStr(i))
If Err.Number = 0 Then ' shape exists
oSh.OLEFormat.Object.Text = CStr(i)
End If
Next i
End Sub

Answer 2

#Steve Rindsberg you had the correct code. Thank you. Here was the final script to obtain the value, and set the value if blank.
For i = 1 To 4
'set oSh to TextBox1, TextBox2, TextBox3... etc.
Set oSh = ActivePresentation.Slides(1).Shapes("TextBox" & CStr(i))
'set myVar to value of this TextBox1, TextBox2...
myVar = oSh.OLEFormat.Object.Value
If myVar = "" Then _
ActivePresentation.Slides(1).Shapes("Text" & CStr(i)).OLEFormat.Object.Value = 0 _
Else: 'do nothing
'clear value of myVar
myVar = ""
'start on next integer of i
Next i