如何處理WP8中的文本塊

Question

這是我的文本塊的代碼，

我想顯示其中兩個數字的差，

但是如果我運行該應用程序，它就會出錯。

Error: System.NullReferenceException was unhandled by user code
  HResult=-2147467261
  Message=Object reference not set to an instance of an object.

這是代碼，

        TextBlock diffBlock = new TextBlock();


        diffBlock.FontSize = 30;

        diffBlock.Text = " ";

        diffBlock.Text = (total - double.Parse(income.Inc)).ToString();

        ContentPanel.Children.Add(diffBlock);

        Difference.Foreground = new SolidColorBrush(Colors.Black);

        Difference.Text = "Remaining Budget: " + diffBlock;

怎么解決？

Answer 1

您不能使用textbolck作為字符串使用Text屬性。 這將解決您的問題。

TextBlock diffBlock = new TextBlock();


        diffBlock.FontSize = 30;

        diffBlock.Text = " ";
      if(income!=null)
        diffBlock.Text = (total - double.Parse(income.Inc)).ToString();
       else
         diffBlock.Text = total.ToString();
         ContentPanel.Children.Add(diffBlock);

        Difference.Foreground = new SolidColorBrush(Colors.Black);

        Difference.Text = "Remaining Budget: " + diffBlock.Text;