AutoComplete

Introduction

This is a simple code snippet which is used to make an Auto Complete ComboBox.

Using the code

Usage: Call the subroutine from within the ComboBox’s KeyPress event handler. 


AutoComplete(ByRef cb As ComboBox, ByVal e As System.Windows.Forms.KeyPressEventArgs, Optional ByVal blnLimitToList As Boolean = False)
  • cb – ComboBox used to make the Auto Complete ComboBox.
  • e – System.Windows.Forms.KeyPressEventArgs used to handle the keyboard inputs.
  • blnLimitToList – Optional Boolean value indicating whether the user input is limited to the list values or not.

Code


    ' AutoComplete
    Public Sub AutoComplete(ByRef cb As ComboBox, ByVal e As System.Windows.Forms.KeyPressEventArgs, Optional ByVal blnLimitToList As Boolean = False)
        Dim strFindStr As String

        If e.KeyChar = Chr(8) Then  'Backspace
            If cb.SelectionStart <= 1 Then
                cb.Text = ""
                Exit Sub
            End If
            If cb.SelectionLength = 0 Then
                strFindStr = cb.Text.Substring(0, cb.Text.Length - 1)
            Else
                strFindStr = cb.Text.Substring(0, cb.SelectionStart - 1)
            End If
        Else
            If cb.SelectionLength = 0 Then
                strFindStr = cb.Text & e.KeyChar
            Else
                strFindStr = cb.Text.Substring(0, cb.SelectionStart) & e.KeyChar
            End If
        End If

        Dim intIdx As Integer = -1

        ' Search the string in the Combo Box List.
        intIdx = cb.FindString(strFindStr)

        If intIdx <> -1 Then ' String found in the List.
            cb.SelectedText = ""
            cb.SelectedIndex = intIdx
            cb.SelectionStart = strFindStr.Length
            cb.SelectionLength = cb.Text.Length
            e.Handled = True
        Else
            If blnLimitToList = True Then
                e.Handled = True
            Else
                e.Handled = False
            End If
        End If
    End Sub

 

History

  • Released on July 30th, 2005.