Non draggable windows form

Thanks Amit. 

Thanks Amit. How can we add reference to it?

Use below function in your child form to non draggable.

protected override void WndProc(ref Message m)
{
    const int WM_NCLBUTTONDOWN = 161;
    const int WM_SYSCOMMAND = 274;
    const int HTCAPTION = 2;
    const int SC_MOVE = 61456;
    if ((m.Msg == WM_SYSCOMMAND) && (m.WParam.ToInt32() == SC_MOVE))
    {
        return;
    }
    if ((m.Msg == WM_NCLBUTTONDOWN) && (m.WParam.ToInt32() == HTCAPTION))
    {
        return;
    }
    base.WndProc(ref m);
}

Read the cocumentation. There are values you can use for FormBorderStyle. I was not sure what you meant by not draggable. I could not be sure that you meant that you wanted the child form to not be draggable outside the main form.

Thank you Sam. I had tried it before but it didn't solve the problem. The child form is still draggable.

No, the child form is not owned by the main form. You need to use frm.ShowDialog(); to get the child form owned by the main form. Or you can use the Owner property. However that is not likely to solve the problem.

MDI is called Multiple-Document Interface. It is designed to support multiple documents, not multiple windows. When MDI is used for multiple general-purpose windows there are problems.

See the following article.

C# Create Child Forms | coding.vision
https://codingvision.net/c-create-child-forms

You can start with that and modify it as needed. The following shows the code from that article with some modifications. The commented out portions are suggestions, you can choose one of the values for `FormBorderStyle`. Since you are not specific with the requirements I cannot be specific with a solution.

Form2 frm = new Form2();
frm.TopLevel = false;
Controls.Add(frm);
//frm.FormBorderStyle = FormBorderStyle.None;
//frm.FormBorderStyle = FormBorderStyle.FixedToolWindow;
//frm.FormBorderStyle = FormBorderStyle.FixedSingle;
frm.StartPosition = FormStartPosition.Manual;
frm.Location = new Point(50, 50);
frm.Show();
frm.BringToFront();

Thanks for your intrest Sam. Yes, the child form is owned by the main form. I am using it like that

VeliGorusmeF frm = new VeliGorusmeF();
frm.ShowDialog();

I am using MDI but I am openeing the child forms over the main form not inside it.

I assume you are not using MDI but if you are then please say so. If the following does not apply then you probably need to be more specific about what you are doing.

Is the child form owned by the main form? When you show the form are you using Show() or Show(this)?