Hi MMOHM,
The shape of Winform button control is not easy to change. That's an easy job for WPF project. But if you still need to use Winform for your project, you can host WPF control into it.
Please read the following sample.
http://msdn.microsoft.com/en-us/library/ms742215.aspx
You should first made your custom button(round corner) control in WPF(with XAML will be ok), then add that button into Winform. ElementHost is the class that can host WPF control.
For the information of making a round corner button in WPF, you can post on WPF forum.
Sincerely,
Kira Qian
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