用户代码未处理 System.NullReferenceException
  Message=未将对象引用设置到对象的实例。
  Source=MonitorClient
  StackTrace:
       在 SuperSight.NSClient.NSMultiPlay.PlayWindow.FindButton(String tag) 位置 C:\Users\Administrator\Desktop\MonitorClient代码 - 副本\SuperSight\NSClient\NSMultiPlay\PlayWindow.cs:行号 630
       在 SuperSight.NSClient.NSMultiPlay.PlayWindow.<>c__DisplayClass51.<set_MicButtonState>b__50() 位置 C:\Users\Administrator\Desktop\MonitorClient代码 - 副本\SuperSight\NSClient\NSMultiPlay\PlayWindow.cs:行号 3259
       在 System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
       在 System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
       在 System.Threading.ExecutionContext.runTryCode(Object userData)
       在 System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
       在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
       在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       在 System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme)
       在 System.Windows.Forms.Control.InvokeMarshaledCallbacks()
  InnerException: