在运行时将一个网格添加为ListBox的一个项目，最终会出现未知错误/崩溃 [英] Adding a grid as an item of a ListBox at runtime ends up with an unknown error/crash

问题描述

在下面的代码中，我试图......

1. 在Grid（mygrid）中放置一个TextBlock（txtDays）（作为行）


2. 将网格放置在ListBox（lsBox）中


3. 最后将ListBox放置到另一个Grid（ContentPanel）中

该程序仅在没有正确错误的情况下崩溃，并且执行此代码时模拟器会停止。如果我把Grid（在2.）放入一个stackPanel或直接放入另一个Grid（在3.）而不放入列表框中，代码就可以工作，但不能与ListBox一起工作。

任何意见和帮助表示感谢。

谢谢。

  private void PhoneApplicationPage_Loaded（object sender，RoutedEventArgs e）
 {
 string [] lstDays = new string [] {Monday，Tuesday ， 周三周四周五周六周日 }; 
 
 //创建一个ListBox 
 ListBox lstBox = new ListBox（）; 
 //网格定义
网格mygrid = new Grid（）; 
 ColumnDefinition c1 = new ColumnDefinition（）; //创建一个列
 mygrid.ColumnDefinitions.Add（c1）; 
 
 int i = -1; 
 foreach（lstDays中的字符串项）
 {
 i + = 1; 
 TextBlock txtDays = new TextBlock（）; //创建一个TextBlock 
 
 RowDefinition r1 = new RowDefinition（）; //创建一行
 mygrid.RowDefinitions.Add（r1）; 
 
 txtDays.Text = item; 
 txtDays.TextAlignment = TextAlignment.Left; 
 if（item ==Thursday）
 {
 txtDays.TextAlignment = TextAlignment.Right; 
 txtDays.Foreground =新的SolidColorBrush（Colors.Green）; 
} 
 
 mygrid.Children.Add（txtDays）; //将TextBlock添加到网格
 Grid.SetRow（txtDays，i）; //将项目放置在网格内的特定行中
 lstBox.Items.Add（mygrid）; //将网格放置在listBox中（此处为ERROR）
 
 
 
 RowDefinition rNewRow = new RowDefinition（）; 
 ContentPanel.RowDefinitions.Add（rNewRow）; 
 ContentPanel.Children.Add（lstBox）; 
} 
  

解决方案

mygrid 到 lstBox 对每个 foreach 迭代。在循环外部添加 lstBox.Items.Add（mygrid）; ，以便仅添加一次。

或者将 mygrid 的定义放在循环中，如果你想要多个网格。

In the code below, I am trying to ...

1. Place a TextBlock(txtDays) inside the Grid(mygrid) (as row)
2. Place the Grid inside a ListBox(lsBox)
3. Finally placing the ListBox into another Grid(ContentPanel)

The program is just crashing without a proper error, and the emulator stops when I execute this code. If I place the Grid (in 2.) inside a stackPanel or directly into the other Grid (in 3.) without placing it into the ListBox, the code works, but not with a ListBox.

Any comments, assistance is appreciated.

Thank you.

    private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e)
    {
        string[] lstDays = new string[] { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday" };

        //Creating a ListBox
        ListBox lstBox = new ListBox();
        //Grid definition
        Grid mygrid = new Grid();
        ColumnDefinition c1 = new ColumnDefinition(); //creating a column
        mygrid.ColumnDefinitions.Add(c1);

        int i = -1;
        foreach (string item in lstDays)
        {
            i += 1;
            TextBlock txtDays = new TextBlock(); //Creating a TextBlock

            RowDefinition r1 = new RowDefinition(); //Creating a row
            mygrid.RowDefinitions.Add(r1);

            txtDays.Text = item;
            txtDays.TextAlignment = TextAlignment.Left;
            if (item == "Thursday")
            {
                txtDays.TextAlignment = TextAlignment.Right;
                txtDays.Foreground = new SolidColorBrush(Colors.Green);
            }

            mygrid.Children.Add(txtDays); //Adding the TextBlock into the grid
            Grid.SetRow(txtDays,i);       //Placing the item in a particular row inside the grid          
            lstBox.Items.Add(mygrid);     //Placing grid inside a listBox (ERROR here)

        }

        RowDefinition rNewRow = new RowDefinition();
        ContentPanel.RowDefinitions.Add(rNewRow);
        ContentPanel.Children.Add(lstBox);
    }

解决方案

You're trying to add mygrid to lstBox on each foreach iteration. Bring lstBox.Items.Add(mygrid); outside the loop so it is added only once.

Either that or put the definition for mygrid inside the loop if you want multiple grids.

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