c# winform中预防窗体重复打开

 1 foreach (Form f in Application.OpenForms)
 2    {
 3                 if (f.Name == "Form1")
 4                 {
 5                     if (f.WindowState == FormWindowState.Minimized)
 6                     {
 7                         f.WindowState = FormWindowState.Normal;
 8                     }
 9                     f.Activate();
10                     f.Show();
11                     return;
12                 }
13     }
14 
15     Form1  f2 =new  Form1();
16      f2.Name = " Form1";
17      f2.Show();