我正在使用WPF表单但是当我添加一个新的WindowsForm表单时，我的程序将运行，但Windows窗体将不会显示

I'm using WPF forms but when I add a new WindowsForm form, my program will run, but the windows form won't display. It says no error, but my program automatically stops debugging when i proceed to launch the windows form form. Can you help me? :'( I'm a student and I'm a beginner in programming.I'm using WPF forms but when I add a new Window