Double buffered painting of a panel

Question

4.00/5 (1 vote)

See more:

I want to set the DoubleBuffered style of a Panel in a Forms application to avoid flickering when painting it.

This requires to call its SetStyle method. This method being protected, you need to derive a new class from Panel.

Unfortunately when you do this, the Designer cannot recognize the Panel object anymore and gets screwed.

Who knows of a workaround ?

Posted 16-Jul-11 9:10am

YDaoust

Add a Solution

3 solutions

Solution 3

I have found the following hack:

1) Derive a class from Forms::Panel to expose the SetStyle method as public. Do this outside of Form1.h.

C#

public ref class MyPanel :  public System::Windows::Forms::Panel
{
public:
    void SetStyle(System::Windows::Forms::ControlStyles flag, System::Boolean value)
    {
        System::Windows::Forms::Control::SetStyle(flag, value);
    }
};

2) When it comes to changing the panel behavior (I do that in the main form constructor), cast the panel pointer the new class type.

static_cast<MyPanel^>(panel1)->SetStyle(ControlStyles::AllPaintingInWmPaint, true);
static_cast<MyPanel^>(panel1)->SetStyle(ControlStyles::DoubleBuffer, true);

This way, the code that the Designer parses remains perfectly untouched.

Posted 17-Jul-11 20:35pm

YvesDaoust

Updated 17-Jul-11 20:44pm

v4

Comments

Dmitri Novikov 19-Jun-12 19:12pm

Didn't succeed this in my C# 2010 game project:( Can't put here exact compiler message because I have a russian version. But it says something like can't access SetStyle because it's a protected member. Any suggestions?

Dmitri Novikov 19-Jun-12 19:21pm

Ah, all posible. Maybe I'm just too weak in C#: this is my first real project using this language and .NET framework. Just do not know how to access parent's method with the same name. When I changed to MySetStyle, all seems to go well, but I will continue tomorrow, it's time to be asleep:)

YvesDaoust 20-Jun-12 10:13am

In C#, I work like this:

in Form1.cs, declare a class like this:

// Trick to allow double buffering
public class DoubleBufferPanel : Panel
{
public DoubleBufferPanel()
{
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
}
}

Then in Form1.Designer.cs, replace the occurrences of the Panel type by the this newly defined class (two places).

Solution 1

Once the application is compiled, the designer should works properly again. So you should close the designer, build the application and open the designer again.

Posted 16-Jul-11 10:30am

Philippe Mori

Comments

YDaoust 17-Jul-11 3:25am

I wish it were so, but it is not. My guess it that when parsing the source code, the Designer comes across an unknown class and does not know what to do with it.

It would be nice to find a way of changing the Panel style bits differently than with SetStyle.

Philippe Mori 17-Jul-11 8:33am

Which version of Visual Studio are you using? Visual Studio 2010 is better for handling designer errors. Less problems and more usefull error reporting.

By the way sometimes, you have to "clean all" or event restart Visual Studio.

Otherwise, you have to ensure that your type is accessible and that you have updated it everywhere it need to be updated.

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Philippe Mori · Accepted Answer · 2011-07-17T12:15:00

This is what I have done (Visual C# 2010 Express) and it works perfectly fine.

Create a new WinForm application project
Drag a panel onto the form
Add an user control to that project
Drop some controls onto that UserControl
Add a public method to give access to SetStyle
Open the *.designer.cs file in the editor and replace Panel by the new user control and also rename the variable and update the code accordingly

Change the type at declaration
Change variable name and let Visual Studio update references
Update the construction of that object to create the newly created user control
Update the name in the comment for that control
Update the name property of that control

Build and run the application
Click on the tab with the designer

Sure enough, my user control with any controls I dropped into it was properly show in my form.

Sometime, it might happen that a Clean or a restart of Visual Studio is required after having some problems but it is rare.