How to make a ComboBox Read Only

Issue: ComboBox Control does NOT have a ReadOnly Property
Level: Intermediate
Knowledge Required: To understand the following solution you must have the knowledge of:

• ComboBox


• AddHandler


• RemoveHandler

Description:
Sometimes it is required to have the ComboBox control to be Read Only i.e. it should just be like a TextBox, from which we can Select and Copy Text but cannot change value and cannot open Drop Down List. For this purpose you can call the following public method ToggleComobBoxReadonly.

For Example:

' This will make the comobbox readonly
ToggleComobBoxReadonly(Me.ComboBox1, True)

Public Sub ToggleComboBoxReadonly(ByRef cmbToUse As ComboBox, ByVal bValue As Boolean)
    If bValue Then
        Dim intHeight As Integer
        intHeight = cmbToUse.Height
        cmbToUse.Tag = cmbToUse.DropDownStyle
        cmbToUse.DropDownStyle = ComboBoxStyle.Simple
        cmbToUse.Height = intHeight
        AddHandler cmbToUse.KeyDown, AddressOf Common.ComboBox_KeyDown
        AddHandler cmbToUse.KeyPress, AddressOf Common.ComboBox_KeyPress
    Else
        If cmbToUse.Tag IsNot Nothing Then
            cmbToUse.DropDownStyle = cmbToUse.Tag
            RemoveHandler cmbToUse.KeyDown, AddressOf Common.ComboBox_KeyDown
            RemoveHandler cmbToUse.KeyPress, AddressOf Common.ComboBox_KeyPress
        End If
    End If
End Sub

Private Sub ComboBox_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs)
    Select Case e.KeyCode
        Case Keys.Delete, Keys.Down, Keys.Up, Keys.PageDown, Keys.PageUp
            e.Handled = True
    End Select
End Sub

Private Sub ComboBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)
    e.Handled = True
End Sub