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.
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.
|This feature will paint the background color of the control.|
|This feature will change the group control color. This color can also be used in combination with |
BackgroundGradientColor for a gradient paint.
|This feature can be used in combination with |
BackgroundColor to create a gradient background.
|This feature turns on background gradient painting.|
|This feature will allow you to change the color of the control's border.|
|This feature will allow you to set the control's border size.|
|This feature will paint the group title background to the specified color if |
PaintGroupBox is set to
|This feature can add a 16 x 16 image to the group title bar.|
|This feature will add a group title to the control.|
|This feature will paint the group title background to the |
|This feature will round the corners of the control.|
|This feature will change the control's shadow color.|
|This feature will allow you to turn on control shadowing.|
|This feature will change the size of the shadow border.|
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:
This code must be added on top of your class as an attribute to your control, like so:
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:
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 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
OnPaintBackground(). Below is the code to override these methods:
protected override void OnPaint(PaintEventArgs e)
protected override void OnPaintBackground(PaintEventArgs pevent)
Grouper, we will be using the
OnPaint() method. The code is shown below:
protected override void OnPaint(PaintEventArgs e)
I receive the control's
Graphics object from the
PaintEventArgs, and pass it to my two custom methods,
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.
private void PaintBack(System.Drawing.Graphics g)
g.SmoothingMode = SmoothingMode.AntiAlias;
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 =
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;
ShadowBrush = new SolidBrush(this.ShadowColor);
ShadowPath = new System.Drawing.Drawing2D.GraphicsPath();
ArcWidth, ArcHeight, 180, GroupBoxConstants.SweepAngle);
ArcWidth, ArcHeight, 270, GroupBoxConstants.SweepAngle);
ArcWidth, ArcHeight, 360, GroupBoxConstants.SweepAngle);
ArcWidth, ArcHeight, 90, GroupBoxConstants.SweepAngle);
path.AddArc(ArcX1, ArcY1, ArcWidth, ArcHeight, 180,
path.AddArc(ArcX2, ArcY1, ArcWidth, ArcHeight, 270,
path.AddArc(ArcX2, ArcY2, ArcWidth, ArcHeight, 360,
path.AddArc(ArcX1, ArcY2, ArcWidth, ArcHeight, 90,
new LinearGradientBrush(new Rectangle(0,0,this.Width,this.Height),
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:
- Dispose off all graphic objects by calling their
- Make sure to check that your graphics objects are not
null before disposing off them.
- If you have common graphics objects among multiple methods, think about declaring them as class variables or constants.
- 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
- 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.
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.
- Version 1.0
HatchBrushTypeEditor completed - January 23, 2006.
- Version 1.0a Beta - December 17, 2005.
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.