Windows CE – building a transparent picturebox

Surprise! PictureBox in Windows CE doesn’t support transparency.

Diving into yet another old forgotten corner of the .NET compact framework.

And just in case the mention of Compact Framework hasn’t scared you to death, today’s code will be in Visual Basic .NET

Imports System.Drawing.Imaging Imports System.ComponentModel

Public Class TransparentPictureBox Inherits PictureBox

Private \_transparentColor As Color = Color.White
Public Property TransparentColor() As Color
    Get
        Return \_transparentColor
    End Get
    Set(ByVal value As Color)
        \_transparentColor = value
    End Set
End Property

Protected Overloads Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)

    If Not Me.Image Is Nothing Then
        Dim pictureBounds As New Rectangle(0, 0, Me.Width, Me.Height)
        Dim imageBounds As New Rectangle(0, 0, Me.Image.Width, Me.Image.Height)
        Dim attributes As New ImageAttributes()
        ' set color to be set to transparent - if you don't paint the background below, then these pixels
        ' will appear black
        attributes.SetColorKey(Me.TransparentColor, Me.TransparentColor)
        e.Graphics.DrawImage(Me.Image, pictureBounds, imageBounds.X, imageBounds.Y, imageBounds.Width, imageBounds.Height, GraphicsUnit.Pixel, attributes)
    End If

End Sub

Protected Overloads Overrides Sub OnPaintBackground(ByVal e As System.Windows.Forms.PaintEventArgs)
    ' paint background color
    Dim brush As SolidBrush
    brush = New SolidBrush(Me.Parent.BackColor)
    e.Graphics.FillRectangle(brush, Me.ClientRectangle)
End Sub

End Class

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