wpf在异步中给前台赋值

 Thread newThread = new Thread(new ParameterizedThreadStart(GetResult));  
            newThread.Start(inputNumber);  

  private void GetResult(object inputNumber)  
        {  
           //错误的方法
           //this.Dispatcher.BeginInvoke((Action)delegate()  
           // {  
           //     this.textBox2.Text = CalcSum((Int64)inputNumber).ToString();  
           //});  
         //正确的方法
         double result=CalcSum((Int64)inputNumber);  
         this.Dispatcher.BeginInvoke((Action)delegate()  
         {  
           this.textBox2.Text = result.ToString();            
        });  
      }  
  
        private double CalcSum(Int64 inputNumber)  
        {  
            double sum=0;  
            for (int i = 0; i < inputNumber; i++)  
            {  
                sum +=i;  
            }  
            return sum;  
        }