显示效果：

FrmWaiting.cs:

1 public FrmWaitingBox(EventHandler
      
        Method,string msg) 2         { 3             InitializeComponent(); 4             if (!string.IsNullOrEmpty(msg)) 5                 lblTip.Text = msg; 6             _Method = Method; 7         } 8 private EventHandler
       
         _Method; 9         private IAsyncResult asyncResult;10         private void timer1_Tick(object sender, EventArgs e)11         {12             if (asyncResult.IsCompleted)13                 this.Close();14         }15         /// 
        
16         /// 窗体第一次加载事件17         /// 
18         /// 
        19         /// 
        20         private void FrmWaitingBox_Shown(object sender, EventArgs e)21         {22             asyncResult = _Method.BeginInvoke(null, null, null,null);23         }
       
      

Form1.cs:

1 private void btnStart_Click(object sender, EventArgs e) 2         { 3             var list = new List
      
       (); 4             FrmWaitingBox waitingBox = new FrmWaitingBox((obj, args) => 5             { 6                 //Thread.Sleep(5000); 7                 for (int i = 1; i <= 50; i++) 8                 { 9                     list.Add(new User {10                         Id=i,11                         UserName="Test"+i,12                         Age=18+i,13                         Birth=DateTime.Now14                     });15                 }16                 //this.Invoke(new Action(() =>17                 //{18                 //    dgvData.DataSource = list;19                 //}));20             },"数据获取中,请等待!");21             waitingBox.ShowDialog(this);22             dgvData.DataSource = list;23         }24         public class User25         {26             public int Id { get; set; }27             public string UserName { get; set; }28             public int Age { get; set; }29             public DateTime Birth { get; set; }30         }
      

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