User Control vs. Windows Form

Question

What is the difference between a user control and a windows form in Visual Studio - C#?

Bill Martin · Accepted Answer · 2010-02-19T21:20:43.217

62

Put very simply:

User controls are a way of making a custom, reusable component. A user control can contain other controls but must be hosted by a form.

Windows forms are the container for controls, including user controls. While it contains many similar attributes as a user control, it's primary purpose is to host controls.

edited Feb 19 '10 at 21:20

answered Feb 19 '10 at 20:36

Bill Martin

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Can user controls host (contain) other user controls? – Robert Niestroj Apr 30 '12 at 13:54
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@RobertNiestroj yes they can. – LxL Jan 02 '14 at 17:43

score 29 · Answer 2 · answered Feb 19 '10 at 20:39

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They have a lot in common, they are both derived from ContainerControl. UserControl however is designed to be a child window, it needs to be placed in a container. Form was designed to be a top-level window without a parent.

You can actually turn a Form into a child window by setting its TopLevel property to false:

public partial class Form1 : Form {
    public Form1() {
        InitializeComponent();
        var child = new Form2();
        child.TopLevel = false;
        child.Location = new Point(10, 5);
        child.Size = new Size(100, 100);
        child.BackColor = Color.Yellow;
        child.FormBorderStyle = FormBorderStyle.None;
        child.Visible = true;
        this.Controls.Add(child);
    }
}

answered Feb 19 '10 at 20:39

Hans Passant

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But you really should avoid doing so, IMO. :) – Dave Markle Feb 20 '10 at 01:57
There is a wee bit of memory you'll use needlessly, very small peanuts compared to the cost of the Control class and especially the native window. It would have been very easy for Microsoft to not expose the TopLevel property. The feature is merely obscure, using it is just fine. – Hans Passant Aug 02 '16 at 10:08
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I guess I was speaking from the standpoint of code clarity and composition. Sure, you can do this, and sure, it's supported, but I think my point was to not take this good example as a design pattern :) – Dave Markle Aug 02 '16 at 12:10

score 4 · Answer 3 · answered Feb 19 '10 at 20:32

4

A windows form is a container for user controls.

answered Feb 19 '10 at 20:32

Ikke

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how do you put a form into a user control!? – Fredou Feb 19 '10 at 20:35
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you can't, but you sure can put a user control in a user control. – Dave Markle Feb 19 '10 at 20:35
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@Dave - You can, actually. See my post. – Hans Passant Feb 19 '10 at 20:40

score 2 · Answer 4 · answered Dec 17 '13 at 14:13

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The biggest difference is form.show gives a different window while usercontrol doesnt have feature like popping up without a parent. Rest things are same in both the controls like beind derived from Scrollablecontrol.

answered Dec 17 '13 at 14:13

sunnytyra

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score 0 · Answer 5 · answered Jul 21 '22 at 18:45

A User Control is a blank control, it's a control that's made up of other controls. Building a user control is similar to building a form. It has a design surface, drag and drop controls onto the design surface, set properties, and events. User controls can consolidate UI and code behind. User controls can only be used in the project where they're defined.

User Control vs. Windows Form

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