绑定到列表框itemTemplate内部 [英] Binding inside listbox itemtemplate problems

问题描述

对于带有包含texbox的itemtemplate的列表框，我有两个单独的绑定问题.

I have two separate binding problems with listboxes with an itemtemplate which contains a texbox.

1)一个列表框绑定到字符串列表.如何在创建的文本框中显示每个字符串，并同时允许双向绑定?如果未指定Path或XPath，则不允许进行双向绑定.

1) One listbox binds to a list of strings. How can I display each string inside the textboxes created and allow two way binding at the same time? Two way binding isn't allowed without specifying a Path or XPath.

<ListBox Height="231" HorizontalAlignment="Left" Margin="0,167,0,0" Name="listBoxKeys" VerticalAlignment="Top" Width="219" ItemsSource="{Binding Path=SelectedPlatform.Keys}" SelectedItem="{Binding Path=SelectedKey,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
         <ListBox.ItemTemplate>
              <DataTemplate>
                  <StackPanel Orientation="Horizontal" Margin="0,0,0,0">
                     <TextBox Text="{Binding Mode=OneWay}" Margin="0,0,0,0" Height="Auto" MinWidth="80" MaxWidth="80" HorizontalAlignment="Left" VerticalAlignment="Center"/>
                   </StackPanel>
               </DataTemplate>
          </ListBox.ItemTemplate>
 </ListBox>

然后2)我使用另一个列表框，该列表框绑定到自定义KeyValuePair类的某些常规列表. itemtemplate包含一个文本框和组合框.文本框文本绑定到每个KeyValuePair对象的key属性，组合框selecteditem绑定到value属性.我的问题是我希望组合由在视图模型中声明的字符串列表填充，该列表将在运行时更改.窗口的数据上下文是声明列表的视图模型.我不知道我需要用来绑定combobox itemssource的确切语法.这是我的代码:

And 2) I use another listbox which binds to some generic list of a custom KeyValuePair class. The itemtemplate contains a textbox and combobox. The textbox text is bound to the key property of each KeyValuePair object and the combobox selecteditem to the value property. My problem is that I want the combo to get filled by a list of strings declared in my viewmodel which will be changing on runtime. The window's datacontext is the viewmodel where the list is declared. I don't know the exact syntax I need to use to bind the combobox itemssource there. Here's my code :

<ListBox Height="393" HorizontalAlignment="Left" Margin="0,72,0,0" Name="listBoxActions" VerticalAlignment="Top" Width="254" ItemsSource="{Binding Path=SelectedPlayer.ControlProfile.MappedActions}">
    <ListBox.ItemTemplate>
      <DataTemplate>
        <StackPanel Orientation="Horizontal" Margin="0,0,0,0">
          <TextBox Text="{Binding Key, Mode=TwoWay,UpdateSourceTrigger=LostFocus}" Margin="10,0,0,0" Height="Auto" MinWidth="80" MaxWidth="80" HorizontalAlignment="Left" VerticalAlignment="Center"/>
          <ComboBox Margin="10,0,0,0" Height="Auto" MinWidth="80" MaxWidth="80" HorizontalAlignment="Left" VerticalAlignment="Center" ItemsSource="{Binding ?}" SelectedItem="{Binding Value, Mode=TwoWay}"/>
         </StackPanel>
        </DataTemplate>
       </ListBox.ItemTemplate>
</ListBox>

推荐答案

问题是，源本身的双向绑定无法工作，因为这将意味着整个对象(字符串)(数据模板是该对象)创建，必须在用户更改文本框中的文本时替换.显然，这是行不通的.双向绑定仅对绑定对象的可写属性起作用.

The problem is that the two-way binding on the source itself cannot work because it would mean that the whole object (string), for which the data template is created, must be replaced when user changes the text in the text box. Obviously, this will not work. Two-way binding will work only on a writable property of the bound object.

在您的情况下，我建议为列表框中的项目创建一个视图模型(基本上是您的字符串的视图模型)，并在其上公开一个Value属性，并将其绑定到数据模板中:

In your case I would suggest creating a view model for the items in the list box (basically a view model for your strings) and expose a Value property on it and bind to it in the data template:

<ListBox Height="231" HorizontalAlignment="Left" Margin="0,167,0,0" 
         Name="listBoxKeys" VerticalAlignment="Top" Width="219" 
         ItemsSource="{Binding Path=SelectedPlatform.KeyViewModels}" 
         SelectedItem="{Binding Path=SelectedKey,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
        <ListBox.ItemTemplate>
             <DataTemplate>
                 <StackPanel Orientation="Horizontal" Margin="0,0,0,0">
                    <TextBox Text="{Binding Value, Mode=TwoWay}" Margin="0,0,0,0" Height="Auto" MinWidth="80" MaxWidth="80" HorizontalAlignment="Left" VerticalAlignment="Center"/>
                  </StackPanel>
              </DataTemplate>
         </ListBox.ItemTemplate>
</ListBox>

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