Create custom winforms container

问题:

I want to create a control in winforms with same behavior as the container controls. I mean: in design mode, when I drop controls in it, it will group then, just like a groupbox.

This control I'm creating contains some other controls AND a GroupBox. All I need is: when a control is droped in design mode over my custom control, I'll just put it inside the nested GroupBox.

But I can't figure out how make my control respond to that kind of action in design mode.

回答1:

Maybe this is what you need, I found it at CodeProject a time ago:

Designing Nested Controls:

This article demonstrates how to allow a Control, which is a child of another Control to accept having controls dropped onto it at design time. It is not a large article, there is not much by way of code, and this may not be either the 'official' or best way to do this. It does, however, work, and is stable as far as I have been able to test it.

回答2:

You need to add a Designer attribute to your control, and use a type that derives from or is the ParentControlDesigner Class (needs a reference to the System.Design.dll assembly), like this:

[Designer(typeof(MyCustomControlDesigner1))]
public partial class CustomControl1 : Control
{
    public CustomControl1()
    {
        MyBox = new GroupBox();
        InitializeComponent();
        MyBox.Text = "hello world";
        Controls.Add(MyBox);
    }

    public GroupBox MyBox { get; private set; }
}

public class MyCustomControlDesigner1 : ParentControlDesigner
{
    // When a control is parented, tell the parent is the GroupBox, not the control itself
    protected override Control GetParentForComponent(IComponent component)
    {
        CustomControl1 cc = (CustomControl1)Control;
        return cc.MyBox;
    }
}