[RESOLVED] Correct ComboBox filtering

Here's a code which should filter and show ComboBox items according to our input,

Code:

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Public Sub CboxAutoComplete(ByVal cbo As ComboBox, ByVal e As System.Windows.Forms.KeyEventArgs)
       
       
        Dim iIndex As Integer
        Dim sActual As String
        Dim sFound As String
        Dim bMatchFound As Boolean

        If e.KeyCode = Keys.Back Then
            'cbo.Text = Mid(cbo.Text, 1, Len(cbo.Text) - 1)
            cbo.Text = ""
        End If

        If ((e.KeyCode = Keys.Left) Or _
        (e.KeyCode = Keys.Right) Or _
        (e.KeyCode = Keys.Up) Or _
        (e.KeyCode = Keys.Down) Or _
        (e.KeyCode = Keys.PageUp) Or _
        (e.KeyCode = Keys.PageDown) Or _
        (e.KeyCode = Keys.Home) Or _
        (e.KeyCode = Keys.End)) Then
            Return
        End If
        Do

            sActual = cbo.Text
            iIndex = cbo.FindString(sActual)
            'if index > -1 then a match was found.
            If (iIndex > -1) Then
                sFound = cbo.Items(iIndex).ToString()
                cbo.SelectedIndex = iIndex
                cbo.SelectionStart = sActual.Length
                cbo.SelectionLength = sFound.Length
                bMatchFound = True
            Else

                If sActual.Length = 1 Or sActual.Length = 0 Then
                    cbo.SelectedIndex = 0
                    cbo.SelectionStart = 0
                    cbo.SelectionLength = Len(cbo.Text)
                    bMatchFound = True
                Else

                    cbo.SelectionStart = sActual.Length - 1
                    cbo.SelectionLength = sActual.Length - 1
                    cbo.Text = Mid(cbo.Text, 1, Len(cbo.Text) - 1)
                End If
            End If
        Loop Until bMatchFound
    End Sub

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Unfortunately, this code have some bugs inside which blocks VS under some circumstances. This simply doesn't work well enough as we'd expect from filtered combo box.

Of course, this code have to be called from an event like this:

Code:

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Private Sub cbox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles cboINtervencija3.KeyDown
        Call CboxAutoComplete(cbox1, e)

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I've tried with debugging but without success. Any idea?

With out really studying your code, I can see right off hand what's your most probable cause for the flickering... The Do...Loop...Until loop. Is there any way that you can restructure it to For...Next loop? Because what if bMatchFound never happens? It will stay in an infinite loop. Also, I noticed that you're using Mid(), that should be replaced by getting the SubString.

Quote:

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Originally Posted by dday9

With out really studying your code, I can see right off hand what's your most probable cause for the flickering... The Do...Loop...Until loop. Is there any way that you can restructure it to For...Next loop? Because what if bMatchFound never happens? It will stay in an infinite loop. Also, I noticed that you're using Mid(), that should be replaced by getting the SubString.

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Yes... the code probably stays trapped into a loop.
About for...next loop, I dunno, Theoretically, possible but it asks to be combine with If...End if, I think. For...Next is "one-dimensional" loop and it wouldn't be so easy to implement.

Might one ask why you're not using the perfectly serviceable autocomplete options built in to the combobox rather than attempting this rather strange and ever so slightly bonkers method? I can't see how the loop you're using ever resolves itself as it simply reads exactly the same values over and over again (to say nothing of the fact that it appears to be seeking whole texts but is activated by a single key press.

Because I don't know that it exists! After a lot of googling I didn't find anything smarter.
BTW, this is .NET v2.0, VS05

Quote:

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.NET v2.0, VS05

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Might be helpful to start with that next time. You'll need someone with either a very good memory or a degree in Ancient History to be definitive about solutions for that! Is there no prospect of joining us in this decade code wise?

VB Code:

Public Sub AutoComplete2(ByVal cbo As ComboBox, ByVal e As KeyEventArgs)
        Dim sTypedText As String
        Dim iFoundIndex As Integer
        Dim oFoundItem As Object
        Dim sFoundText As String
        Dim sAppendText As String
        Select Case e.KeyCode
            Case Keys.Back, Keys.Left, Keys.Right, Keys.Up, Keys.Delete, Keys.Down
                Return
        End Select
        sTypedText = cbo.Text
        iFoundIndex = cbo.FindString(sTypedText)
        If iFoundIndex >= 0 Then
            oFoundItem = cbo.Items(iFoundIndex)
            sFoundText = cbo.GetItemText(oFoundItem)
            sAppendText = sFoundText.Substring(sTypedText.Length)
            cbo.Text = sTypedText & sAppendText
            cbo.SelectionStart = sTypedText.Length
            cbo.SelectionLength = sAppendText.Length
        End If
    End Sub

VB Code:

Public Sub AutoCompleteCombo_Leave(ByVal cbo As ComboBox)
        Dim iFoundIndex As Integer
        iFoundIndex = cbo.FindStringExact(cbo.Text)
        cbo.SelectedIndex = iFoundIndex
    End Sub

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vb Code:

Private Sub cbox1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs)
        AutoComplete2(cbox1, e)
    End Sub

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This one works fine