How to set background color to transparent for a richtextbox in c#

Question

I want to set the background color of the richtextbox to transparent In c# can you help me please Its a winform application

Transparent with respect to what? There is a reason RichTextBox doesn't support transparency, and that's because it is difficult decide what to show behind it. It can be anywhere in a component hierarchy. For it to draw itself, then, it needs to know something about all the components up the tree. You can hack it to be transparent all the way through the form, but you've not been clear about what you are trying to achieve. — J..., Sep 20 '14 at 12:05
That is not an option, not supported by the native Windows control. It can be made to work on Windows 8 but that's not something you can count on today. Windows 7 is the new XP. — Hans Passant, Sep 20 '14 at 12:08

Mehdi Khademloo · Accepted Answer · 2014-09-20T17:42:29.263

11

    public class TransparentLabel : RichTextBox
    {
        public TransparentLabel()
        {
            this.SetStyle(ControlStyles.Opaque, true);
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer, false);
            this.TextChanged += TransparentLabel_TextChanged;
            this.VScroll += TransparentLabel_TextChanged;
            this.HScroll += TransparentLabel_TextChanged;
        }

        void TransparentLabel_TextChanged(object sender, System.EventArgs e)
        {
            this.ForceRefresh();
        }
        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams parms = base.CreateParams;
                parms.ExStyle |= 0x20;  // Turn on WS_EX_TRANSPARENT
                return parms;
            }
        }
        public void ForceRefresh()
        {
            this.UpdateStyles();
        }
    }

and the answer is look like this: enter image description here

edited Sep 20 '14 at 17:42

answered Sep 20 '14 at 12:29

Mehdi Khademloo

2,754
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It's work completely and perfectly. Just use this control – Mehdi Khademloo Sep 20 '14 at 13:28
What is your mean?? Just a feature in c#, by setting the style in a control. What is your mean? – Mehdi Khademloo Sep 20 '14 at 13:50
It doesn't do anything(i tested it). – γηράσκω δ' αεί πολλά διδασκόμε Sep 20 '14 at 14:08
Wait a minute. I have to put an image for this... – Mehdi Khademloo Sep 20 '14 at 14:09
@valter the answer was a bit wrong, but now, it's OK. excuse me :) – Mehdi Khademloo Sep 20 '14 at 14:54
And now try to change one of the Label's Text during runtime.. – TaW Sep 20 '14 at 15:01
Can you please explain how to use this code ? – Muhammad Nasir Khan Sep 20 '14 at 16:50
@TaW yes, it's true. i'm trying to solve this – Mehdi Khademloo Sep 20 '14 at 17:15
@MuhammadNasirKhan the easiest way to this is: Drag a RichTextBox1 to form and go to the Form1.Designer.cs and replace the RichTextBox1 to TransparentLabel (don't forget the namespace) – Mehdi Khademloo Sep 20 '14 at 17:18
@TaW the problem solved :) – Mehdi Khademloo Sep 20 '14 at 17:42
1

Hardly. There simply is no real tranparency in Winforms Controls. Period. If you don't take my word, aks Hans or MSDN. It only can be faked. – TaW Sep 20 '14 at 18:10
@TaW Yes, The winForm basically dose not support the transparency background of control, but we can do some trick for this, like this that i'm mentioned before: http://stackoverflow.com/questions/25830079/how-to-make-the-background-of-a-label-transparent-in-c-sharp/25830214#25830214 – Mehdi Khademloo Sep 20 '14 at 18:15
The problem with this is that it will no update when things below change. Even if you notice and update that background image, the control on top will not notice it,; it only asks its parent once, upon creation, for the background its transparent parts are supposed to shine through. After that it'll show just that old image. To workaround that you'd have to delete and re-create the control..Not so much a workaround but a deep hack. – TaW Sep 20 '14 at 18:19
these just some **trick** not absolute answer... – Mehdi Khademloo Sep 20 '14 at 18:21
Hm, I just played around a little and have to admit, it works better than I had expected. May well be good enough for the OP! – TaW Sep 20 '14 at 18:36
Try to move the *RichTextBox* and see what happens. No tranparency. Game over. – γηράσκω δ' αεί πολλά διδασκόμε Sep 20 '14 at 20:42

How to set background color to transparent for a richtextbox in c#

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