How to: Create Variable Sized Text in a ComboBox Control

This example demonstrates custom drawing of text in a ComboBox control. When an item meets a certain criteria, it is drawn in a larger font and turned red.

Example

Private Sub ComboBox1_MeasureItem(ByVal sender As Object, ByVal e As _
System.Windows.Forms.MeasureItemEventArgs) Handles ComboBox1.MeasureItem
    Dim bFont As New Font("Arial", 8, FontStyle.Bold)
    Dim lFont As New Font("Arial", 12, FontStyle.Bold)
    Dim siText As SizeF

    If ComboBox1.Items().Item(e.Index) = "Two" Then
        siText = e.Graphics.MeasureString(ComboBox1.Items().Item(e.Index), _
lFont)
    Else
        siText = e.Graphics.MeasureString(ComboBox1.Items().Item(e.Index), bFont)
    End If

    e.ItemHeight = siText.Height
    e.ItemWidth = siText.Width
End Sub

Private Sub ComboBox1_DrawItem(ByVal sender As Object, ByVal e As _
System.Windows.Forms.DrawItemEventArgs) Handles ComboBox1.DrawItem
    Dim g As Graphics = e.Graphics
    Dim bFont As New Font("Arial", 8, FontStyle.Bold)
    Dim lFont As New Font("Arial", 12, FontStyle.Bold)

    If ComboBox1.Items().Item(e.Index) = "Two" Then
        g.DrawString(ComboBox1.Items.Item(e.Index), lfont, Brushes.Red, _
e.Bounds.X, e.Bounds.Y)
    Else
        g.DrawString(ComboBox1.Items.Item(e.Index), bFont, Brushes.Black, e.Bounds.X, e.Bounds.Y)
    End If
End Sub

Compiling the Code

This example requires:

• A Windows form.

• A ComboBox control named ListBox1 with three items in the Items property. In this example, the three items are named "One", Two", and Three". The DrawMode property of ComboBox1 must be set to OwnerDrawVariable.

  Note

  This technique is also applicable to the ListBox control — you can substitute a ListBox for the ComboBox.

• References to the System.Windows.Forms and System.Drawing namespaces.

See also

• DrawItem
• DrawItemEventArgs
• MeasureItem
• Controls with Built-In Owner-Drawing Support
• ListBox Control
• ComboBox Control