Setting MdiParent Background Image properly

Question

I am using below code to set background image of MdiParent form ,and it is working well ,but when I click on maximize button than BackgroundImage is repeating at rightside and bottom edge(i.e right side and bottom side Image portion is repeating) ,how do I avoid this and display Image properly ?

public Parent()
{
    InitializeComponent();

    foreach (Control ctl in this.Controls)
    {
        if (ctl is MdiClient)
        {
            ctl.BackgroundImage = Properties.Resources.bg;
            ctl.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch;
            break;
        }
    }
}

Solution 1

this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch;

this points to Form.

Myself too noticed the same behavior you mentioned. It seems just a painting issue. Add the following code to fix it.

protected override void OnSizeChanged(EventArgs e)
{
    base.OnSizeChanged(e);
    this.Refresh();
}

Solution 2

The MdiClient.BackgroundImageLayout is not relevant for the class MdiClient (as stated by the MSDN document page). You should try some work-around. One of the work-around is paint the BackgroundImage yourself:

MdiClient client = Controls.OfType<MdiClient>().First();
client.Paint += (s, e) => {
   using(Image bg = Properties.Resources.bg){
     e.Graphics.DrawImage(bg, client.ClientRectangle);
   }
};
//Set this to repaint when the size is changed
typeof(Control).GetProperty("ResizeRedraw", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)
              .SetValue(client, true, null);
//set this to prevent flicker
typeof(Control).GetProperty("DoubleBuffered", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)
               .SetValue(client, true, null);

Comments

[Sriram Sakthivel]

@Durga Updated my answer

[user1703401]

The image needs to be disposed.

[King King]

@HansPassant thank you, I'm not sure how it should be done to dispose the image. Could you review my updated code?

[Nathan F.]

@HansPassant The image is being disposed. The "using" statement disposes of the object once it's finished running