Windows forms button background transparent

Question

I have WPF app with ContentControl where the content is WindowsFormsHost with a Child having custom panel, which renders SDL stream. Now I have added button to disable/enable audio of the stream. Everything works fine, but I cannot make the button icon transparent. How can I do that? Is it possible at all?

AudioButton = new System.Windows.Forms.Button()
{
   Enabled = AudioButtonEnabled,
   BackColor = Color.Transparent,
   Image = Image.FromFile(@".\Images\audioDisabled.png"),
   Width = 30,
   Height = 30,
   FlatStyle = System.Windows.Forms.FlatStyle.Flat
};
AudioButton.FlatAppearance.BorderSize = 0;
AudioButton.Click += (object sender, EventArgs e) =>
{
   
};
SDLRenderer.AddButton(AudioButton);

The image (icon) is transparent as well.

Answer 1

The workaround can be to create custom WinForms button, override OnPaint event and make the specified color transparent for bitmap by calling Bitmap.MakeTransparent()

public class CustomButton : Button
{
    private Color TransparentColor;

    public CustomButton() : base()
    {
        TransparentColor = Color.FromArgb(192, 192, 192);
    }
    protected override void OnPaint(PaintEventArgs e)
    {
        if (this.Image != null)
        {
            Bitmap bmp = ((Bitmap)this.Image);
            bmp.MakeTransparent(TransparentColor);
            int x = (this.Width - bmp.Width) / 2;
            int y = (this.Height - bmp.Height) / 2;
            e.Graphics.DrawImage(bmp, x, y);
        }
        base.OnPaint(e);
    }
}