Using api sendmessage in .net

[tommyk]

Hi

I am using the following code to search for a given string in either a listbox or a combo box, but the function always returns the index as "-1". The function fires from the change event of a textbox.

This is a program that I am converting from vb6.0, so I think that there may have been a problem in translation. There were two upgrade warnings, which I have left in in code, as they may be the root of the problem!

SendMessage Declaration:

    Public Declare Function SendMessage Lib "User32" Alias "SendMessageA" (ByVal hWnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByRef lParam As String) As Integer
    Public Const CB_FINDSTRING As Short = &H14Cs
    Public Const CB_FINDSTRINGEXACT As Short = &H158s
    Public Const LB_FINDSTRING As Short = &H18Fs
    Public Const LB_FINDSTRINGEXACT As Short = &H1A2s

Function Call:

Index = FindFirstMatch(lstProductCode, txtProductCode.Text, -1, False)

Function:

Public Function FindFirstMatch(ByVal ctlSearch As System.Windows.Forms.Control, ByVal SearchString As String, ByVal FirstRow As Short, ByVal Exact As Boolean) As Short
 
        Dim Index As Integer
 
        'UPGRADE_WARNING: TypeOf has a new behavior. Click for more: 'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?keyword="9B7D5ADD-D8FE-4819-A36C-6DEDAF088CC7"'
        If TypeOf ctlSearch Is System.Windows.Forms.ComboBox Then
            If Exact Then
                Index = SendMessage(ctlSearch.Handle.ToInt32, CB_FINDSTRINGEXACT, FirstRow, SearchString)
            Else
                Index = SendMessage(ctlSearch.Handle.ToInt32, CB_FINDSTRING, FirstRow, SearchString)
            End If
            'UPGRADE_WARNING: TypeOf has a new behavior. Click for more: 'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?keyword="9B7D5ADD-D8FE-4819-A36C-6DEDAF088CC7"'
        ElseIf TypeOf ctlSearch Is System.Windows.Forms.ListBox Then
            If Exact Then
                Index = SendMessage(ctlSearch.Handle.ToInt32, LB_FINDSTRINGEXACT, FirstRow, SearchString)
            Else
                Index = SendMessage(ctlSearch.Handle.ToInt32, LB_FINDSTRING, FirstRow, SearchString)
            End If
        End If
 
        FindFirstMatch = Index
 
        If Index <> -1 Then
            Call frmMain.Populate_Screen(VB6.GetItemString(frmMain.lstProductCode, Index))
        End If
 
    End Function

Any help will be greatly appriciated!

Many Thanks

Tom

[tommyk]

Sorry, I just realised I havent actually asked a question.

Basicly, I would like to know how to fix this code - as it is obviously not working correctly! i need it to return the index number of the closest match in the list box to the search string.

I really need any help you can give me, as I have a deadline to meet!

Many Thanks

Tom