CODEWITHSUNDEEP
c#winforms
bebosh
bebosh

Reputation: 863

WinForm: How to implement button with correct background colors

I'm developing winform app with C#. And I created custom button inherent from UserControl as shown below:

public partial class UserButton : UserControl
{
    public UserButton(string UserID)
    {
        this.Size = new Size(32, 50);
        this.BackColor = Color.Transparent;
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        Graphics g = e.Graphics;
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
        Img = WaseelaMonitoring.Properties.Resources.T;
        g.DrawImage(Img, 0, 0, this.Size.Width, this.Size.Height);           
    }
}

Note: this is button png image (Click here)

Now, I want to show some buttons on picture box using this code:

UserButton TagButton1 = new UserButton("Button1");
TagButton1.Location = Points[0];
UserButton TagButton2 = new UserButton("Button2");
TagButton2.Location = Points[1];
UserButton TagButton3 = new UserButton("Button3");
TagButton1.Location = Points[2];
Picturebox1.Controls.Add(TagButton1);
Picturebox1.Controls.Add(TagButton2);
Picturebox1.Controls.Add(TagButton2);
Picturebox1.Invalidate();

Okay, when show only one button on the picture box, the background button is transparent(as I want) like this:

enter image description here

But if I want to show two or more buttons beside together the background button is white not transparent like this:

enter image description here

I'm using invalidate picture box and trying invalidate button also, but is not solve that problem.

Upvotes: 1

Views: 220

Answers (2)

bebosh
bebosh

Reputation: 863

I solved this problem by added this line to initializing constructor:

SetStyle(ControlStyles.Opaque, true);

And overridden this function:

    protected override CreateParams CreateParams
    {
        get
        {
            const int WS_EX_TRANSPARENT = 0x00000020;
            CreateParams cp = base.CreateParams;
            cp.ExStyle |= WS_EX_TRANSPARENT;
            return cp;
        }
    }

Upvotes: 0

Dai
Dai

Reputation: 154995

WinForms does not support true Z-ordering of components; windowed controls (such as Button and UserControl) cannot have true alpha-channel support, and the this.Background - Color.Transparent trick is actually a special-case where the control will re-paint its parent's Background image or color to itself first.

If you are after a more flexible user-experience, I suggest switching to WPF, or doing all of your painting within a single WinForms Control.

Upvotes: 3

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