(PPT VBA) Select textrange.characters failure - vba

Question

I want to select some characters in textrange. It works when I use "With activepresentation.slides(2).shapes(2)".
The codes:
dim Txtrng as textrange
dim Words_Instr as integer
dim aa as string
With ActivePresentation.Slides(2).Shapes(2)
Set Txtrng = .TextFrame.textRange
aa = "AAAA"
Words_Instr = InStr(Txtrng, aa)
If Words_Instr > 0 Then
Txtrng.Characters(Words_Instr, Len(aa)).Select
end if
end with
It doesn't work when I use "pres.". I want to do the same thing in every shape of every slide.
The Codes:
dim pres as presentation
dim sli as slide
dim shp as shape
dim Txtrng as textRange
dim Words_Instr as integer
dim aa as string
set pres=Presentations.Open(filename:=f1)
aa = "AAAA"
For Each sLi In pRes.Slides
for each sHp in sLi.shapes
If sHp.HasTextFrame = msoTrue Then
Set Txtrng = sHp.TextFrame.textRange
Words_Instr = InStr(Txtrng, aa)
If Words_Instr > 0 Then
Txtrng.Characters(Words_Instr, Len(aa)).Select
end if
end if
next
next
It always showed error in “txtrng.characters(...).select”
I will be grateful for any help.

Answer 1

If you only refer to current presentation instead of open another ppt, then the following code will do, I only change set pre part only, copy and paste this code into your existing ppt and run it, it will select the text on the shape:
Sub test()
Dim pres As Presentation
Dim sli As Slide
Dim shp As Shape
Dim Txtrng As TextRange
Dim Words_Instr As Integer
Dim aa As String
Set pres = ActivePresentation
aa = "AAAA"
For Each sli In pres.Slides
For Each shp In sli.Shapes
If shp.HasTextFrame = msoTrue Then
Set Txtrng = shp.TextFrame.TextRange
Words_Instr = InStr(Txtrng, aa)
If Words_Instr > 0 Then
Txtrng.Characters(Words_Instr, Len(aa)).Select
End If
End If
Next
Next
End Sub