綁定多個視圖模型

Question

我有一個用於viewmodel的數據模板中定義的usercontrol的viewmodel。我想將usercontrol的'GridViewData'屬性綁定到viewmodel的'Data'屬性。

我還是新的WPF和可怕的綁定，所以請善待：對

XAML：

<Window x:Class="ReportUtility.MainWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:lite="clr-namespace:ReportUtility.Controls.LiteGrid" 
    xmlns:vm="clr-namespace:ReportUtility.ViewModels" 
    xmlns:wf="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms" 
    Title="MainWindow" Height="350" Width="525"> 

<!--This is the view model I want to bind to variable name is Grid: hosted in the content control below--> 
<Window.Resources> 
    <DataTemplate DataType="{x:Type vm:LiteGridViewModel}"> 
     <lite:LiteGrid GridViewData="{Binding ??}"/> 
    </DataTemplate> 
</Window.Resources> 

<Grid> 
    <Grid.RowDefinitions> 
     <RowDefinition Height="auto"/> 
     <RowDefinition Height="50"/> 
     <RowDefinition Height="*"/> 
    </Grid.RowDefinitions> 
    <Grid.ColumnDefinitions> 
     <ColumnDefinition/> 
     <ColumnDefinition Width="150"/> 
    </Grid.ColumnDefinitions> 

    <Button Grid.Row="0" Content="TestButton" HorizontalAlignment="Stretch" Command="{Binding ExecuteQueryCommand}"/> 
    <TextBox Grid.Row="1" Text="{Binding Path=SqlCommandText, UpdateSourceTrigger=PropertyChanged}"/> 
    <ContentControl Content="{Binding Grid}" Grid.Row="2" Background="Red"/> 

    <Border Background="Aqua" Grid.Column="1" Grid.RowSpan="3"/> 
    <GridSplitter Grid.Column="0" Width="3" Grid.RowSpan="3"/> 
</Grid> 

Answer 1

你會綁定到Data

<DataTemplate DataType="{x:Type vm:LiteGridViewModel}"> 
    <lite:LiteGrid GridViewData="{Binding Data}"/> 
</DataTemplate> 

在LiteGrid中做這個綁定甚至會更好UserControl而不是依賴使用控件設置值的XAML。

<UserControl GridViewData="{Binding Data}"> 
    ... 
</UserControl> 

您的綁定始終引用當前對象的DataContext。由於您的DataTemplate適用於LiteGridViewModel類型，因此DataTemplate中的DataContext始終爲LiteGridViewModel。

舉例來說，如果你有一個像

public class MyClassA 
{ 
    MyClassB ClassB {get; set;} 
} 

public class MyClassB 
{ 
    MyClassC ClassC {get; set;} 
} 

類和MyClassA ClassA一個ViewModel財產（這意味着你可以參考ClassA.ClassB.ClassC），你可以不喜歡

<ContentControl Content="{Binding ClassA}"> 
    <ContentControl Content="{Binding ClassB}"> <!-- DataContext is MyClassA --> 
     <ContentControl Content="{Binding ClassC}"> <!-- DataContext is MyClassB --> 
      <!-- DataContext is MyClassC --> 
     </ContentControl> 
    </ContentControl> 
</ContentControl>