参考《图解C#》第20章异步编程第五节程序，解决在wpf中连接数据库，界面假死问题。

public partial class MainWindow : Window
 {
      private bool isConnected = false;
      public MainWindow()
      {
          InitializeComponent();
          startWorkButton.Click += async (sender, e) =>
          {
              SetGuiValues(false, "正在连接数据库");
              await DoSomeWork();
              if (isConnected==true)
              {
                  SetGuiValues(true, "数据库连接成功");
              }
              else
              {
                  SetGuiValues(true, "数据库连接失败");
              }
          };
      }

      /// <summary>
      /// 模拟连接数据库
      /// </summary>
      /// <returns></returns>
      private Task DoSomeWork()
      {
          Random random = new Random();
          int rndValue = random.Next(0, 10);
          if (rndValue%3==0)
          {
              isConnected = true;
          }
          else
          {
              isConnected = false;
          }
          return Task.Delay(2500);
      }

      private void SetGuiValues(bool buttonEnabled, string status)
      {
          startWorkButton.IsEnabled = buttonEnabled;
          workStartedTextBlock.Text = status;
      }
  }