The Grouper - A Custom Groupbox Control

• Download source files - 77 Kb
• Download HatchBrushTypeEditor source code only - 29.1 Kb

Introduction

The Grouper is a special group box control that is rounded and fully customizable. The control can paint borders, drop shadows, and has other features like gradient and solid backgrounds, custom text, and custom icons. The purpose of this control is to design a better looking group box WinForms control. I used the (Keep it Simple Stupid) philosophy to design a tight knitted re-useable control that I hope you all will enjoy. This control is still in beta version, but it seems to be stable.

Using the code

Before you add the control, you must add a reference (CodeVendor.Controls) to your project.

using CodeVendor.Controls;

The Grouper control can be added to your project with the following code. Add this code to your class.

private CodeVendor.Controls.Grouper Grouper1;
this.Grouper1 = new CodeVendor.Controls.Grouper();

Custom Control Properties

Below is a list of the Grouper control properties that change the physical appearance of the control.

Grouper Source Code

I started off writing this control because I was tired of the plain old Windows GroupBox. My WinForms application group box needed an updated XP look with round edges and gradient backgrounds. Like most developers writing controls, I thought to myself, should I custom draw the original GroupBox control, or reinvent the wheel and start from the ground up? I chose to reinvent the wheel :).

Re-inventing the wheel gave me the power to draw the control without flicker and customize it to my preferences. Taking the time to make a control from the ground up seems long and futile, but having the satisfaction of knowing that I wrote the code and if anything breaks it's because of something I wrote and not someone else is fully worth it.

To start off designing the control, I had to figure out how the original GroupBox acts as a container for other controls during design mode. Below is the code for turning any control into a design-time container control:

[Designer("System.Windows.Forms.Design.ParentControlDesigner, 
           System.Design", typeof(IDesigner))]

This code must be added on top of your class as an attribute to your control, like so:

[Designer("System.Windows.Forms.Design.ParentControlDesigner, 
                        System.Design", typeof(IDesigner))]
public class Grouper : System.Windows.Forms.UserControl
{
}

Once the attribute is added to your control, the control will now automatically turn into a design-time control Container. Wow! Very easy and self contained, Microsoft sure does think of everything. The URL I found for this resource is: Microsoft support.

Since that took hardly anytime at all to add such power to my control, I decided to invest more time into where the original GroupBox left off, which was the design.

Painting a Control Without Flicker

If you are painting your own custom control, you should think about "What is the best way to paint without Flicker?". To paint without flicker, you need a way to double buffer your drawing or graphics. Microsoft has given us an option for this using control styles. The code below shows how to add double buffering to your control:

//Set the control styles----------------------------------

this.SetStyle(ControlStyles.DoubleBuffer, true);
this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
this.SetStyle(ControlStyles.UserPaint, true);
this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
//--------------------------------------------------------

This code should be added to the constructor of your class. All of the styles are needed to create a non-flicker control. If you want to make a custom double buffer, you can create the same effect by drawing all graphics to an off-screen bitmap, and then drawing the bitmap to the screen all at once. This will virtually create the same effect as the code above. Also, notice this style:

this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);

This style allows any control to support transparent colors. By default, user controls cannot support transparent colors. So you must enable this to add transparency to your back-color property.

Let's continue on with the painting of our custom painted control. To paint a user control, you need to override one of two methods depending on the desired effect. The two methods are OnPaint() and OnPaintBackground(). Below is the code to override these methods:

protected override void OnPaint(PaintEventArgs e)
{
  base.OnPaint (e);
}
        
protected override void OnPaintBackground(PaintEventArgs pevent)
{
  base.OnPaintBackground (pevent);
}

For the Grouper, we will be using the OnPaint() method. The code is shown below:

/// <SUMMARY>Overrides the OnPaint method to paint control.</SUMMARY>

protected override void OnPaint(PaintEventArgs e)
{
  PaintBack(e.Graphics);
  PaintGroupText(e.Graphics);
}

I receive the control's Graphics object from the PaintEventArgs, and pass it to my two custom methods, PaintBack() and PaintGroupText().

Creating a Rounded Control

So, you want to create a rounded custom user control? It is pretty simple to create a rounded control using the GDI+ library. Let's dive into the code to find out how it works.

/// <SUMMARY>This method will paint the control.</SUMMARY>

private void PaintBack(System.Drawing.Graphics g)
{
  //Set Graphics smoothing mode to Anit-Alias-- 

  g.SmoothingMode = SmoothingMode.AntiAlias;
  //-------------------------------------------


  //Declare Variables------------------

  int ArcWidth = this.RoundCorners * 2;
  int ArcHeight = this.RoundCorners * 2;
  int ArcX1 = 0;
  int ArcX2 = (this.ShadowControl) ? (this.Width - (ArcWidth + 1))- 
               this.ShadowThickness : this.Width - (ArcWidth + 1);
  int ArcY1 = 10;
  int ArcY2 = (this.ShadowControl) ? (this.Height - (ArcHeight + 1))-
               this.ShadowThickness : this.Height - (ArcHeight + 1);
  System.Drawing.Drawing2D.GraphicsPath path = 
                        new System.Drawing.Drawing2D.GraphicsPath();
  System.Drawing.Brush BorderBrush = new SolidBrush(this.BorderColor);
  System.Drawing.Pen BorderPen = new Pen(BorderBrush, this.BorderThickness);
  System.Drawing.Drawing2D.LinearGradientBrush BackgroundGradientBrush = null;
  System.Drawing.Brush BackgroundBrush = new SolidBrush(this.BackgroundColor);
  System.Drawing.SolidBrush ShadowBrush = null;
  System.Drawing.Drawing2D.GraphicsPath ShadowPath  = null;
  //-----------------------------------


  //Check if shadow is needed----------

  if(this.ShadowControl)
  {
    ShadowBrush = new SolidBrush(this.ShadowColor);
    ShadowPath = new System.Drawing.Drawing2D.GraphicsPath();
    ShadowPath.AddArc(ArcX1+this.ShadowThickness, ArcY1+this.ShadowThickness, 
                      ArcWidth, ArcHeight, 180, GroupBoxConstants.SweepAngle);
                      // Top Left

    ShadowPath.AddArc(ArcX2+this.ShadowThickness, ArcY1+this.ShadowThickness, 
                      ArcWidth, ArcHeight, 270, GroupBoxConstants.SweepAngle);
                      //Top Right

    ShadowPath.AddArc(ArcX2+this.ShadowThickness, ArcY2+this.ShadowThickness, 
                      ArcWidth, ArcHeight, 360, GroupBoxConstants.SweepAngle);
                      //Bottom Right

    ShadowPath.AddArc(ArcX1+this.ShadowThickness, ArcY2+this.ShadowThickness, 
                      ArcWidth, ArcHeight, 90, GroupBoxConstants.SweepAngle);
                      //Bottom Left

    ShadowPath.CloseAllFigures();

    //Paint Rounded Rectangle------------

    g.FillPath(ShadowBrush, ShadowPath);
    //-----------------------------------

  }
  //-----------------------------------


  //Create Rounded Rectangle Path------

  path.AddArc(ArcX1, ArcY1, ArcWidth, ArcHeight, 180, 
              GroupBoxConstants.SweepAngle); // Top Left

  path.AddArc(ArcX2, ArcY1, ArcWidth, ArcHeight, 270, 
              GroupBoxConstants.SweepAngle); //Top Right

  path.AddArc(ArcX2, ArcY2, ArcWidth, ArcHeight, 360, 
              GroupBoxConstants.SweepAngle); //Bottom Right

  path.AddArc(ArcX1, ArcY2, ArcWidth, ArcHeight, 90, 
              GroupBoxConstants.SweepAngle); //Bottom Left

  path.CloseAllFigures(); 
  //-----------------------------------


  //Check if Gradient Mode is enabled--

  if(this.BackgroundGradientMode==GroupBoxGradientMode.None)
  {
    //Paint Rounded Rectangle------------

    g.FillPath(BackgroundBrush, path);
    //-----------------------------------

  }
  else
  {
    BackgroundGradientBrush = 
      new LinearGradientBrush(new Rectangle(0,0,this.Width,this.Height), 
      this.BackgroundColor, this.BackgroundGradientColor, 
      (LinearGradientMode)this.BackgroundGradientMode);
                
    //Paint Rounded Rectangle------------

    g.FillPath(BackgroundGradientBrush, path);
    //-----------------------------------

  }
  //-----------------------------------


  //Paint Borded-----------------------

  g.DrawPath(BorderPen, path);
  //-----------------------------------


  //Destroy Graphic Objects------------

  if(path!=null){path.Dispose();}
  if(BorderBrush!=null){BorderBrush.Dispose();}
  if(BorderPen!=null){BorderPen.Dispose();}
  if(BackgroundGradientBrush!=null){BackgroundGradientBrush.Dispose();}
  if(BackgroundBrush!=null){BackgroundBrush.Dispose();}
  if(ShadowBrush!=null){ShadowBrush.Dispose();}
  if(ShadowPath!=null){ShadowPath.Dispose();}
  //-----------------------------------

}

The PaintBack() method above uses the GraphicsPath() method from the System.Drawing.Drawing2D class to create four arcs starting in the order of Top Left, Top Right, Bottom Right, and Bottom Left. The arcs need to be set to TopLeft: 180, TopRight: 270, BottomRight: 360 and BottomLeft: 90, with a sweep angle of 90. The CloseAllFigures() method of the GraphicsPath closes all of these arcs together for you, creating a rounded rectangle path. All that is left to do is to fill your path, using the FillPath() method. You can also choose from a solid brush or linear gradient brush for the background of the group box. To draw a border around the control, I use the DrawPath() method of the graphics library. By passing the same path to this method with a graphics pen, you can create a line border that follows the same path.

Disposing off Graphic Objects!

So many coders including myself forget to dispose() off the graphics brushes, pens, paths, colors, etc. Leaving unmanaged resources open can cause memory leaks, and will eventually slow your machine down to a dead stop. Make sure you follow these common rules whenever you are using the graphics library:

1. Dispose off all graphic objects by calling their dispose() methods.
2. Make sure to check that your graphics objects are not null before disposing off them.
3. If you have common graphics objects among multiple methods, think about declaring them as class variables or constants.
4. Don't rely on the garbage collector to auto collect your used graphic resources.

Control Improvements Needed

• The group title bar does not size properly to an increased font size.
• The control needs to be able to shrink to minimum height and width, without drawing over itself.
• The group title bar needs to be able to accept icons bigger than 16 x 16, and expand to the appropriate size.
• Some fonts have an issue reporting exact sizes when measured with the measurestring() method.
• Option to minimize the group box, and a user button to minimize.
• This has been completed: a background HatchBrush.
• Custom control designer with preset options.
• Bevel designer.
• Drop shadow in any direction.
• Half gradient background.
• TypeEditor with multi-layer drawing and blending pad.

HatchBrushTypeEditor

I felt the need to design a custom type editor for hatch styles. This will be added as a selection for the Grouper's custom coloring and styles.

Please let me know about any improvements or features you would like to see with the 1.0 version of this control.

History

• Version 1.0 HatchBrushTypeEditor completed - January 23, 2006.
• Version 1.0a Beta - December 17, 2005.

Screenshots

Awards

• December 2005 - CodeProject C# prize winner.
• December 2005 - PlanetSourceCode contest winner...Thanks!

Terms and Conditions For Use, Copy, Distribution, and Modification

THIS CODE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS CODE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.