if (this.txtLoginName.Text.Trim()=="admin" && this.txtLoginPwd.Text.Trim()=="")

             {

                 this.DialogResult = DialogResult.OK;

                 this.Close();

             }

             else

             {

                 MessageBox.Show("用户名或密码错误", "信息提示");

             }

 static class Program

     {

         /// <summary>

         /// 应用程序的主入口点。

         /// </summary>

         [STAThread]

         static void Main()

         {

             Application.EnableVisualStyles();

             Application.SetCompatibleTextRenderingDefault(false);

             LoginFrm lf = new LoginFrm();

             lf.ShowDialog();

             if (lf.DialogResult == DialogResult.OK)

             {

                 Application.Run(new MainFrm());

             }

             else return;

         }

     }