wpf Combobox Itemssource在Listbox数据模板中没有绑定 [英] wpf Combobox Itemssource not binding within Listbox Data Template

问题描述

请帮助解决以下问题。我在列表框项目datatemplate中有Combobox，这样我就可以加载多个组合框但是相同的项目源

Please help to fix the below issue. I have Combobox inside listbox item datatemplate so that I can load multiple combobox but same itemsource

<StackPanel>
  <ListBox Width="400" Name="lstFiles" ItemsSource="{Binding}">
    <ListBox.ItemTemplate>
      <DataTemplate>
        <Grid Name="dataGrid">
          <Grid.RowDefinitions>
            <RowDefinition/>
          </Grid.RowDefinitions>
          <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
            <ColumnDefinition/>
          </Grid.ColumnDefinitions>
          <TextBox Name="dragFileName"

                   Margin="5,0,0,0"

                   Text="{Binding fileName, UpdateSourceTrigger=Default}" />
          <ComboBox Grid.Row="0"

                    Grid.Column="1"

                    Margin="5,0,0,0"

                    Name="cboDragDocType"

                    ItemsSource="{Binding dragDocType, UpdateSourceTrigger=LostFocus, Mode=TwoWay}"  

                    Text="{Binding dragDocTypeText}"

                    IsEditable="True"

                    IsReadOnly="True" />
          <Button Name="dragDelBtn"

                  Grid.Column="2"

                  Height="20">X</Button>
        </Grid>
      </DataTemplate>
    </ListBox.ItemTemplate>
  </ListBox>
</StackPanel>

Data is loading in comboBox by using ObservableCollection property. In Initialize method i do for loop method to get multiple items. Problem scenario: Select item from the dropdown1 --> then Select item from the dropdown2 -->Again click dropdown1, Now dropdown1 itemssource is empty.

推荐答案

有一些奇怪的行为一个约束迷路了。

我遇到了类似于组合框和文本框的东西，Textbox.Text绑定到DependencyProperty的ID属性，而DependencyProperty又绑定到组合框的SelectedItem;用户可以输入id，反向选择函数会更新绑定到ComboBox.SelectedItem的属性（不直接到ComboBox.SelectedItem，预计会破坏绑定）。

最后，我存储了BindingExpression，并在ComboBox_DropDownOpened中重新应用它。

不是一个漂亮的解决方案，更多的是WTF，但是它有效。

也许这样的解决办法可以对你的情况也很有帮助。

There is some strange behavior of a binding getting lost.
I experienced something similar with a combination of a combobox and a textbox, with Textbox.Text bound to the ID property of a DependencyProperty which is in turn bound to the SelectedItem of the combobox; the user could type the id and a reverse selection function would update that property which is bound to ComboBox.SelectedItem (not to ComboBox.SelectedItem directly, that would be expected to break the binding).
Eventually, I stored the BindingExpression, and re-applied it in ComboBox_DropDownOpened.
Not a beautiful solution, more of a WTF, but it works.
Perhaps such a work-around could be helpful in your case, too.

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