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Writing Your Custom Control: Step by Step

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31 Mar 20022 min read 853.3K   21.7K   239   75
Making a cute button of two semi-transparent user-changeable colors

Sample Image - cuteButton.jpg

Introduction

This is a short and simple demonstration of .NET Framework's capability of creating custom controls.

Here, I'm going to make a custom control and then, test my control in a Windows application. I have implemented some custom properties for my control, so you can learn how it is done in C#.

Building the Control

  1. Open Visual Studio and start a new project. Your project must be based on the Windows Control Library template. Call your project ctlCuteButton and click OK.

  2. Once you have your project open, delete the UserControl from the project. Just remove it because the 'User Control' is not exactly what we need here.

  3. Now go to the 'Project' menu: Project->Add User Control... and select the Custom Control template there. 'Custom Control' is what we need in this case. You may call it cuteButton. Now click OK. A new Custom control has been added to your project.

  4. The first thing we must do here is change the base class of the cuteButton:

    Override the following line:

    C#
    public class cuteButton : System.Windows.Forms.Control

    by this one:

    C#
    public class cuteButton : System.Windows.Forms.Button

    Now your control is based on the System.Windows.Forms.Button class.

  5. Now let's create some custom properties for our control. This is done by inserting the following code inside the cuteButton class:

    C#
    private Color m_color1 = Color.LightGreen;  //first color
    private Color m_color2 = Color.DarkBlue;    // second color
    private int m_color1Transparent = 64;       // transparency degree 
                                                // (applies to the 1st color)
    private int m_color2Transparent = 64;       // transparency degree 
                                                //  (applies to the 2nd color)
    
    public Color cuteColor1
    {
        get { return m_color1; }
        set { m_color1 = value; Invalidate(); }
    }
    
    public Color cuteColor2
    {
        get { return m_color2; }
        set { m_color2 = value; Invalidate(); }
    }
    
    public int cuteTransparent1
    {
        get { return m_color1Transparent; }
        set { m_color1Transparent = value; Invalidate(); }
    }
    
    public int cuteTransparent2
    {
        get { return m_color2Transparent; }
        set { m_color2Transparent = value; Invalidate(); }
    }

    The Invalidate() method is used to refresh the design view and all controls inside (the tip from Tom Welch).

  6. And the last thing to do before compiling our control is to override the Paint event. So let's do it:

    C#
    // Calling the base class OnPaint
    base.OnPaint(pe);
    // Create two semi-transparent colors
    Color c1 = Color.FromArgb(m_color1Transparent , m_color1);
    Color c2 = Color.FromArgb(m_color2Transparent , m_color2);
    Brush b = new System.Drawing.Drawing2D.LinearGradientBrush(ClientRectangle, 
                                                               c1, c2, 10);
    pe.Graphics.FillRectangle (b, ClientRectangle);
    b.Dispose();
  7. Now you may compile the control by pressing <Ctrl>+<Shift>+<B>.

Here is the complete contents of cuteButton.cs file (just in case…):

Complete Code

C#
using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;

namespace ctlCuteButton
{
    /// <summary>
    /// Summary description for cuteButton.
    /// </summary>

    public class cuteButton : System.Windows.Forms.Button
    {
    private Color m_color1 = Color.LightGreen; // first color
    private Color m_color2 = Color.DarkBlue;   // second color
    private int m_color1Transparent = 64;      // transparency degree 
                                               // (applies to the 1st color)
    private int m_color2Transparent = 64;      // transparency degree 
                                               // (applies to the 2nd color)

    public Color cuteColor1
    {
        get { return m_color1; }
        set { m_color1 = value; Invalidate(); }
    }

    public Color cuteColor2
    {
        get { return m_color2; }
        set { m_color2 = value; Invalidate(); }
    }

    public int cuteTransparent1
    {
        get { return m_color1Transparent; }
        set { m_color1Transparent = value; Invalidate(); }
    }

    public int cuteTransparent2
    {
        get { return m_color2Transparent; }
        set { m_color2Transparent = value; Invalidate(); }
    }

    public cuteButton()
    {
    }

    protected override void OnPaint(PaintEventArgs pe)
    {
        // Calling the base class OnPaint
        base.OnPaint(pe);
        // Create two semi-transparent colors
        Color c1 = Color.FromArgb
            (m_color1Transparent , m_color1);
        Color c2 = Color.FromArgb
            (m_color2Transparent , m_color2);
        Brush b = new System.Drawing.Drawing2D.LinearGradientBrush
            (ClientRectangle, c1, c2, 10);
        pe.Graphics.FillRectangle (b, ClientRectangle);
        b.Dispose();
    }
}
}

Testing the Control

  1. Open a new instance of the VS .NET. Create a new project choosing the Windows Application template.

  2. From a new Windows Forms project, we can add the compiled custom control to the toolbox. I do this by right-clicking the toolbox, selecting Customize Toolbox, and from the .NET Framework Components tab, clicking Browse and locating the Control Library DLL # (in our case, ctlCuteButton\bin\debug\cuteButton.dll). The component cuteButton will then appear in the Toolbox.

    You can play a bit changing its properties (cuteColor1, cuteColor2, cuteTransparent1, cuteTransparent2).

That’s all so far about building and using custom controls.

Good luck.

History

  • 25th March, 2002: Initial version

License

This article has no explicit license attached to it, but may contain usage terms in the article text or the download files themselves. If in doubt, please contact the author via the discussion board below.

A list of licenses authors might use can be found here.


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Comments and Discussions

 
QuestionSuper Pin
Member 84713099-Dec-11 2:48
Member 84713099-Dec-11 2:48 
GeneralMy vote of 5 Pin
GuyThiebaut29-Oct-11 6:21
professionalGuyThiebaut29-Oct-11 6:21 
GeneralMy vote of 4 Pin
Member 772135016-Apr-11 0:50
Member 772135016-Apr-11 0:50 
GeneralGood Job Pin
Nueman9-Feb-11 16:36
Nueman9-Feb-11 16:36 
QuestionIs it PRO version required? Pin
BogdanJankowski1-Mar-10 4:27
BogdanJankowski1-Mar-10 4:27 
QuestionHow to anchor a custom control? Pin
Ryo-kun010110-Nov-09 17:01
Ryo-kun010110-Nov-09 17:01 
GeneralThanks Pin
rutstyle20-Jun-09 0:09
rutstyle20-Jun-09 0:09 
AnswerWindows Forms Control Library =~ Windows Control Library, also a partial class error Pin
dblanchard17-Mar-09 15:00
dblanchard17-Mar-09 15:00 
In VS 2008 Pro, I couldn't find the Windows Control Library template; from running through this example, the Windows Forms Control Library template seems to be functionally the same.

If I'm wrong, or just overlooking something, please correct me.

Also, I got a an error in VS 2008 when compiling:
Error 1 Missing partial modifier on declaration of type 'ctlCuteButton.cuteButton'; another partial declaration of this type exists C:\Documents and Settings\...\My Documents\Visual Studio 2008\Projects\...\Project1\ctlCuteButton\ctlCuteButton\cuteButton.cs 12 18 ctlCuteButton

Changing to the following fixed it, but I'm too noobian to understand the error:
public partial class cuteButton : System.Windows.Forms.Button

modified on Tuesday, March 17, 2009 10:19 PM

General3Ks Pin
whatcsu3-Aug-08 13:14
whatcsu3-Aug-08 13:14 
GeneralThanks Pin
Laurent Cozic2-Aug-08 9:10
Laurent Cozic2-Aug-08 9:10 
QuestionInclude control during runtime Pin
Vagga Raghavendra10-Aug-07 20:06
Vagga Raghavendra10-Aug-07 20:06 
GeneralLoad custom control dynamically Pin
VINH TRAN20-Jul-07 12:11
VINH TRAN20-Jul-07 12:11 
GeneralNice... Pin
ESTAN13-Jul-07 13:41
ESTAN13-Jul-07 13:41 
GeneralThanks! Just what I needed Pin
halciber10-Apr-07 9:36
professionalhalciber10-Apr-07 9:36 
GeneralTransparent control Pin
Arijit Datta8-Mar-07 20:38
Arijit Datta8-Mar-07 20:38 
GeneralMany thx! Pin
flyingchen10-Feb-07 19:21
flyingchen10-Feb-07 19:21 
Generalvery good Pin
Zhi Chen1-Feb-07 15:33
Zhi Chen1-Feb-07 15:33 
Questioncustom control on window ce Pin
lanbuithe31-Jan-07 15:57
lanbuithe31-Jan-07 15:57 
QuestionTo make Scrollable Contextmenustrip Pin
jeyaseelanmca5-Dec-06 17:31
jeyaseelanmca5-Dec-06 17:31 
QuestionHow lock to change the font and colour Pin
Nata;19-Jun-06 23:58
Nata;19-Jun-06 23:58 
GeneralDoes not work for textbox Pin
monal12315-May-06 20:59
monal12315-May-06 20:59 
QuestionInstaller for your new control. Pin
Bertus Kruger15-Mar-06 12:10
Bertus Kruger15-Mar-06 12:10 
Generalusing UserControl for application webform Pin
onebitcuongdv7-Dec-05 0:32
onebitcuongdv7-Dec-05 0:32 
Generalgreat job Pin
bmustata19-Feb-05 9:10
bmustata19-Feb-05 9:10 
Generalcustomer controls Pin
abidkayani13-Jan-05 10:40
abidkayani13-Jan-05 10:40 

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