WPF中的多重绑定

MultiBinding 将会给后端传回一个数组, 其顺序为绑定的顺序. 例如:

        <DataGridMargin="10"AutoGenerateColumns="False"ItemsSource="{Binding Stu}"><DataGrid.Columns><DataGridTextColumn Binding="{Binding Id}" Header="Id" /><DataGridTextColumn Binding="{Binding Name}" Header="Name" /><DataGridTextColumn Binding="{Binding Age}" Header="Age" /><DataGridTextColumn Binding="{Binding Description}" Header="Description" /><DataGridTemplateColumn><DataGridTemplateColumn.CellTemplate><DataTemplate><ButtonWidth="60"HorizontalAlignment="Center"Command="{Binding RelativeSource={RelativeSource AncestorType=UserControl}, Path=DataContext.MyButtonCommand}"CommandParameter="{Binding}"Content="申请"><Button.Style><Style TargetType="Button"><!--<Setter Property="IsEnabled" Value="{Binding Age, Converter={StaticResource SingleParamConverter}}" />--><Setter Property="IsEnabled"><Setter.Value><MultiBinding Converter="{StaticResource MultiParamConverter}"><Binding Path="Age"/><Binding Path="Id"/></MultiBinding></Setter.Value></Setter></Style></Button.Style></Button></DataTemplate></DataGridTemplateColumn.CellTemplate></DataGridTemplateColumn></DataGrid.Columns></DataGrid>

在这里的 Button 的isEnabled属性用了多重绑定给converter, 用来筛选条件

                                        <Setter Property="IsEnabled"><Setter.Value><MultiBinding Converter="{StaticResource MultiParamConverter}"><Binding Path="Age"/><Binding Path="Id"/></MultiBinding></Setter.Value></Setter>

这时 后端转换器为:

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;namespace NavTest.Components
{public class MultiParamConverter : IMultiValueConverter{public object Convert(object[] values,Type targetType,object parameter,CultureInfo culture){int age;int id;if (values == null){return true;}int.TryParse(values[0].ToString(), out age);int.TryParse(values[1].ToString(), out id);if (age > 1 && id > 5){return true;}return false;}public object[] ConvertBack(object value,Type[] targetTypes,object parameter,CultureInfo culture){throw new NotImplementedException();}}
}

效果:

完整代码:

view:

<UserControlx:Class="NavTest.Views.Page5"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:cv="clr-namespace:NavTest.Components"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:hc="https://handyorg.github.io/handycontrol"xmlns:i="http://schemas.microsoft.com/xaml/behaviors"xmlns:local="clr-namespace:NavTest.Views"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:mv="clr-namespace:NavTest.ViewModels"d:DataContext="{d:DesignInstance mv:Page5ViewModel}"d:DesignHeight="450"d:DesignWidth="800"mc:Ignorable="d"><UserControl.Resources><cv:SingleParamConverter x:Key="SingleParamConverter" /><cv:MultiParamConverter x:Key="MultiParamConverter" /></UserControl.Resources><Grid><Grid.ColumnDefinitions><ColumnDefinition /><ColumnDefinition /></Grid.ColumnDefinitions><Grid.RowDefinitions><RowDefinition /><RowDefinition /></Grid.RowDefinitions><DataGridMargin="10"AutoGenerateColumns="False"ItemsSource="{Binding Stu}"><DataGrid.Columns><DataGridTextColumn Binding="{Binding Id}" Header="Id" /><DataGridTextColumn Binding="{Binding Name}" Header="Name" /><DataGridTextColumn Binding="{Binding Age}" Header="Age" /><DataGridTextColumn Binding="{Binding Description}" Header="Description" /><DataGridTemplateColumn><DataGridTemplateColumn.CellTemplate><DataTemplate><ButtonWidth="60"HorizontalAlignment="Center"Command="{Binding RelativeSource={RelativeSource AncestorType=UserControl}, Path=DataContext.MyButtonCommand}"CommandParameter="{Binding}"Content="申请"><Button.Style><Style TargetType="Button"><!--<Setter Property="IsEnabled" Value="{Binding Age, Converter={StaticResource SingleParamConverter}}" />--><Setter Property="IsEnabled"><Setter.Value><MultiBinding Converter="{StaticResource MultiParamConverter}"><Binding Path="Age"/><Binding Path="Id"/></MultiBinding></Setter.Value></Setter></Style></Button.Style></Button></DataTemplate></DataGridTemplateColumn.CellTemplate></DataGridTemplateColumn></DataGrid.Columns></DataGrid></Grid>
</UserControl>

viewModel:

using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using NavTest.Eneities;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;namespace NavTest.ViewModels
{public partial class Page5ViewModel:ObservableObject{public Page5ViewModel(){for (int i = 0; i < 10; i++){Stu.Add(new(){Id = i + 2,Age = $"{i}",Name = $"Name{i}",Description = $"Description{i}"});}}[ObservableProperty]private ObservableCollection<Student> stu = new();[RelayCommand]public void MyButton(Student s){MessageBox.Show(s.Name);}}
}

转换器:

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;namespace NavTest.Components
{public class MultiParamConverter : IMultiValueConverter{public object Convert(object[] values,Type targetType,object parameter,CultureInfo culture){int age;int id;if (values == null){return true;}int.TryParse(values[0].ToString(), out age);int.TryParse(values[1].ToString(), out id);if (age > 1 && id > 5){return true;}return false;}public object[] ConvertBack(object value,Type[] targetTypes,object parameter,CultureInfo culture){throw new NotImplementedException();}}
}

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;namespace NavTest.Components
{public class SingleParamConverter : IValueConverter{public object Convert(object value, Type targetType, object parameter, CultureInfo culture){if (value == null){return true;}int age;int.TryParse(value.ToString(), out age);if (age > 5){return true;}return false;}public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture){throw new NotImplementedException();}}
}