是否可以将WPF Combobox.SelectedValue绑定到多个ObjectDataProviders？ [英] Is it possible to bind WPF Combobox.SelectedValue to multiple ObjectDataProviders?

问题描述

尝试确定是否可以使用XAMAL Bindings将ComboBox的SelectedValue绑定到多个ObjectDataProvider的输入。

Trying to determine if it is possible to bind the SelectedValue of a ComboBox to the inputs of multiple ObjectDataProviders with XAMAL Bindings.

我查看了MultiBinding，但是似乎将多个控件组合在一起，而不是我正在寻找的一天。

I looked at MultiBinding but that appears to be grouping multiple controls together, not exactly what I'm looking to day.

我希望能够让ComboBox（位置）更改TextBlock（偏差），它调用ObjectDataProvider（CommentProvider）来更新TextBox（locationComments）。

I'd like to be able to have the ComboBox (locations) change the TextBlock (deviance) which it does AND to call the ObjectDataProvider (CommentProvider) to update the TextBox (locationComments).

这在代码隐藏中是相当简单的，但更愿意不去这条路线作为学习经验。

This is fairly straightforward in a code-behind but would prefer to not go this route as a learning experience.

XAMAL CODE

XAMAL CODE

<Window.Resources>
    <ObjectDataProvider x:Key="LocationProvider"
        ObjectType="{x:Type srv:ServiceClient}"
        IsAsynchronous="True"MethodName="GetAssignedLocations" />
    <ObjectDataProvider
        x:Key="DevianceProvider"
        ObjectType="{x:Type srv:ServiceClient}"
        IsAsynchronous="True" MethodName="GetPercentChange">
        <ObjectDataProvider.MethodParameters>
            <system:String>Location1</system:String>
        </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
    <ObjectDataProvider
        x:Key="CommentProvider"
        ObjectType="{x:Type srv:ServiceClient}"
        IsAsynchronous="True"
        MethodName="GetCommentByBusinessUnit">
        <ObjectDataProvider.MethodParameters>
            <system:String>Location1</system:String>
        </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
</Window.Resources>

<ComboBox Height="23" HorizontalAlignment="Left" Margin="12,12,0,0" Name="locations"  VerticalAlignment="Top" ItemsSource="{Binding Source={StaticResource LocationProvider}}"
              DisplayMemberPath="BuName" SelectedValuePath="BuKey"
              SelectionChanged="locations_SelectionChanged">
        <ComboBox.SelectedValue>
            <Binding Source="{StaticResource DevianceProvider}"
             Path="MethodParameters[0]"   
                 BindsDirectlyToSource="True" 
                 Mode="OneWayToSource" />
        </ComboBox.SelectedValue>
<TextBlock Name="deviance" Height="23" Margin="0,0,645,17" Width="40" Text="{Binding Source={StaticResource DevianceProvider}}" IsEnabled="False" />

<TextBox Height="23" Margin="0,0,181,17" Name="locationComments" Width="350" />

推荐答案

您在MultiBinding的正确轨道上。
关键是将MultiValueCoverter与MultiBinding一起使用。

You're on the right track with the MultiBinding. The key is to use a MultiValueCoverter in conjunction with the MultiBinding.

<MultiBinding Converter="{StaticResource Coverter_LocationMultiConverter}"
              Mode="OneWayToSource">
                <Binding Source="{StaticResource DevianceProvider}"
                         Path="MethodParameters[0]"
                         BindsDirectlyToSource="True"
                         Mode="OneWayToSource" />
                <Binding Source="{StaticResource CommentProvider}"
                         Path="MethodParameters[0]"
                         BindsDirectlyToSource="True"
                         Mode="OneWayToSource" />
            </MultiBinding>

我们之前绑定了一件事，现在我们将它绑定到了ObjectDataProviders。让我们这样做的关键因素是转换器：

Where we were binding to just one thing before, now we are binding it to both ObjectDataProviders. The key factor that lets us do this is the converter:

public class LocationMultiCoverter : IMultiValueConverter
{
    #region IMultiValueConverter Members

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        return new object[] { value, value };
    }

    #endregion
}

因为我们在两个地方只需要相同的值，CovertBack方法很简单，但是我相信你可以看到它可以用来解析一些复杂的东西，并将不同的组件传回UI中的不同的地方。

Because we just need the same value in both places the CovertBack method is quite simple, however I'm sure you can see that it could be used to parse some complex stuff and pass back different components to different places in the UI.

使用此转换器，我们还可以尝试一个小样本，使用两个文本框：

Using this converter we can also try out a small sample, using two text boxes instead:

<Window x:Class="Sample.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:Sample"
    Title="Window1"
    Height="300"
    Width="300">
<Window.Resources>
    <local:LocationMultiCoverter x:Key="Coverter_LocationMultiConverter" />
</Window.Resources>
<Grid>
    <StackPanel>
        <TextBlock x:Name="uiDeviance" />
        <TextBlock x:Name="uiComment" />
        <ComboBox x:Name="uiLocations"
                  Height="23"
                  HorizontalAlignment="Left"
                  VerticalAlignment="Top"
                  SelectedValuePath="Content">
            <ComboBoxItem>1</ComboBoxItem>
            <ComboBoxItem>2</ComboBoxItem>
            <ComboBoxItem>3</ComboBoxItem>
            <ComboBoxItem>4</ComboBoxItem>
            <ComboBoxItem>5</ComboBoxItem>
            <ComboBox.SelectedValue>
                <MultiBinding Converter="{StaticResource Coverter_LocationMultiConverter}"
                              Mode="OneWayToSource">
                    <Binding ElementName="uiDeviance"
                             Path="Text"
                             BindsDirectlyToSource="True" />
                    <Binding ElementName="uiComment"
                             Path="Text"
                             BindsDirectlyToSource="True" />
                </MultiBinding>
            </ComboBox.SelectedValue>
        </ComboBox>
    </StackPanel>
</Grid>

（在我的例子中的转换器存在于窗口的代码中作为一个单独的类）
当您可以看到测试时，它将在SelectedValue更改时更新两个TextBox。

(The Converter in my example exists in the Window's code behind as a separate class) And as you can see testing this out it will update both TextBoxes when the SelectedValue changes.

这篇关于是否可以将WPF Combobox.SelectedValue绑定到多个ObjectDataProviders？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！