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Asked:2020-03-07 20:24:46 +0000 UTC2020-03-07 20:24:46 +0000 UTC

WPF。Datacontext 中的命令

  • 772

有一个视图模型。

public class VM_searchResult : DependencyObject, INotifyPropertyChanged
{
    private CCard createdCard;    

    private Commands selectSpravInfo;
    public Commands SelectSpravInfo
    {
         get
         {
            return selectSpravInfo ?? (selectSpravInfo = new Commands(obj =>
              {
               W_selectSprav wSelectSprav = new W_selectSprav(obj as CCard);
               wSelectSprav.ShowDialog();
              }));
         }
    }
    public CCard CreatedCard
    {
        get { return createdCard; }
        set
        {
            createdCard = value;
            OnPropertyChanged("CreatedCard");
        }
    }
}

看法

<StackPanel Orientation="Horizontal" DataContext="{Binding CreatedCard}">
       <TextBlock Text="Номер регистрации:" Margin="10,7,0,0" TextWrapping="Wrap" VerticalAlignment="Top"/>
       <TextBox x:Name="TB_regnum" Text="{Binding Regnum}" Margin="10,7,0,0" VerticalAlignment="Top" MinWidth="90"/>
       <TextBlock Text="База данных:" Margin="10,7,0,0" TextWrapping="Wrap" VerticalAlignment="Top"/>
       <Button x:Name="B_selectDB_card" Command="{Binding SelectSpravInfo}" CommandParameter="{Binding CreatedCard}" Content="..." Margin="10,7,0,0" VerticalAlignment="Top" Width="20"/>
       <TextBox x:Name="TB_db_card" Text="{Binding Bdncpi._name}" Margin="10,7,15,0" TextWrapping="Wrap" VerticalAlignment="Top" IsEnabled="False" MinWidth="200"/>
</StackPanel>

在这种情况下，会在实际不存在SelectSpravInfo的上下文中查找该命令。CreatedCard因此问题是，如何摆脱这种情况？以某种方式为每个文本框规定一个上下文是不好的。

c#

2 个回答

  1. Best Answer

    VM_searchResult我们为其数据上下文（您要绑定的命令所在的位置）的元素命名。接下来，通过绑定所需的属性ElementName

    <UserControl x:Name="root"> <!--DataContext устанавливается например сверху -->
    <StackPanel DataContext="{Binding CreatedCard}">    
        <Button Command="{Binding ElementName=root, Path=DataContext.SelectSpravInfo}" CommandParameter="{Binding ElementName=root, Path=DataContext.CreatedCard}"/>      
    </StackPanel>
</UserControl>
    • 2

  2. 解决方案。为视图命名x:Name="root"，然后将其用作 DataContext="{Binding ElementName=root}" Command="{Binding Path=DataContext.SelectSpravInfo}"

    • 1

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