Replacing Text Automatically

I'm not sure how this code is to be used, so I set up a test program with a single textbox and with newStr defined as a form-level string. I tried this code in both the textbox.KeyPress and Form.KeyPress handlers. In both cases it did the replacement but left the first character of the 4-char code within the textbox, which I fixed by adding a fourth chr(8) to the replacement string.

I could only get the routine to put in the extra "-" character by changing the code to use

Textbox.Text &= chr(8) ... 'etc

instead of SendKeys and, when I did this, it actually put the caret and the "-" character at the start of the text box!

I found that setting e.KeyChar=Chr(0) prevented the "-" character from appearing in the textbox.

I also simplified the string handling by removing the "n" & "tmpStr" variables and the for-loops and this is the code I ended up with;

Static newStr As String

newStr &= LCase(e.KeyChar)

If e.KeyChar = vbBack Then
   newStr = If(newStr.Length > 1, newstr.substring(0, newstr.length-1), newStr)
End If

If newStr.Length = 4 Then
    If newStr(3) = "-" AndAlso InStr("123-", newStr) Then
        My.Computer.Keyboard.SendKeys(Chr(8) & Chr(8) & Chr(8) & Chr(8) & dicRepStr(newStr))
        newStr = ""
    Else
        newStr = newStr.Substring(1)
    End If
End If

Hope this helps.

Now I understand the cause of your problem - I hadn't realized that the text was being entered into a different program. The previous suggestions of setting e.Handled=True or setting e.KeyChar=chr(0) assumed that the text was entered into the same program as was doing the substitution. In order to do what you want you would need to clear the pending character from the input buffer of the active program and I don't know how to do that I'm afraid.

The nearest I can get is to delete the extra character after it has been appended to the text. Because the substitution occurs before the unwanted character is appended, I've deferred the deletion until the next character is entered (see variable "SubstitutionMade") so you can just keep typing the rest of your text and the extra character will get removed automatically.

I used example code from http://sim0n.wordpress.com/2009/03/28/vbnet-keyboard-hook-class/[^] to provide a global keyboard hook.

Private WithEvents kbHook As New KeyboardHook

 Private Sub kbHook_KeyDown(ByVal Key As System.Windows.Forms.Keys) Handles kbHook.KeyDown
     Static newStr As String
     Static SubstitutionMade As Boolean

     If SubstitutionMade Then
         My.Computer.Keyboard.SendKeys(Chr(8))
         SubstitutionMade = False
     End If

     newStr &= LCase(Chr(Key))

     If Key = Keys.Back AndAlso newStr.Length > 1 Then
         newStr = newStr.Substring(0, newStr.Length - 1)
     End If

     If newStr.Length = 4 Then
         If Key = Keys.OemMinus AndAlso InStr("xyz", newStr.Substring(0, 3)) >= 1 Then   'Instr(rkset, newStr.substring(0,3))
             SubstitutionMade = True
             My.Computer.Keyboard.SendKeys(Chr(8) & Chr(8) & Chr(8) & "ABCD")   'dicRepStr(newStr))
             newStr = ""
         Else
             newStr = newStr.Substring(1)
         End If
     End If
 End Sub

For testing I used a hard-coded "xyz-" as the 4-character code and a hard-coded "ABCD" as its replacement; these values are still in the code but the trailing comments show what you will need to change.

Note: the keyboard hook supplies a Windows.Forms.Keys value which wouldn't match with "-", which is why I used

Key = Keys.OemMinus

and is why I changed the dictionary look-up to only match the 1st three characters (if you always terminate on a "-" then there is no need to store that character anyway).

Hope this helps