I found that The background of the WPF button can be transparent, but the Window Form button can't. I have tried many methods which I found but it doesn't work. However, is it possible to make a WPF button in a Windows Form?
It is possible to use WPF-Elements in Windows-Forms-Applications. Add a reference to WindowsFormsIntegration.dll in your project, which enables you to use ElementHost. Then you can create a WPFControlLibrary containing your transparent button and use in the ElementHost in the Form.