WPF MVVM模式开发简明实现教程 5 使用MultiValueConverter进行多参数事件绑定

WPF MVVM模式开发实现简明教程 1 开篇简介 

WPF MVVM模式开发实现简明教程 2 初识 INotifyPropertyChanged

WPF MVVM模式开发简明实现教程 3 事件绑定   

WPF MVVM模式开发实现简明教程 3-1 BaseCommand  

WPF MVVM模式开发实现简明教程 4 ViewModelBase  

WPF MVVM模式开发简明实现教程 5 使用MultiValueConverter进行多参数事件绑定 

WPF MVVM模式开发简明实现教程 6 其他绑定  

WPF MVVM模式开发简明实现教程 7 DevExpress MVVM  

WPF MVVM模式开发简明实现教程 8 完结 附全部代码  

 

一个事件有多个参数时，前面的方法就不能用了

虽然多个参数情况不多，还可以避免，但有必要知道下怎么做

 

View增加个button，只为了做参数传递

<Button Content="Binding 2" Height="40" VerticalAlignment="Bottom" x:Name="button2"></Button>

Model目录下增加ButtonModel.cs类

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namespace WpfApp6.Model {     using System.Windows.Controls;       public class ButtonModel     {         public Button btn1 { get; set; }           public Button btn2 { get; set; }     } }

　

这个model是你要传递的多个参数，多个就继续增加就行，这里只演示2个

 

Converter目录下增加个类ButtonMultiValueConverter.cs

namespace WpfApp6.Converter
{
    using System;
    using System.Globalization;
    using System.Windows.Controls;
    using System.Windows.Data;
    using WpfApp6.Model;

    public class ButtonMultiValueConverter : IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            Button btn1 = values[0] as Button;
            Button btn2 = values[1] as Button;

            ButtonModel b = new ButtonModel();
            b.btn1 = btn1;
            b.btn2 = btn2;

            return b;
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

 

这个实现了IMultiValueConverter接口，values包含你传的参数，还是多个就处理多个

 

Style目录下增加资源字典文件MultiValueConverterResource.xaml

资源文件也区分开来，方便管理

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<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"                     xmlns:multiValueConverter="clr-namespace:WpfApp6.Converter"                     xmlns:local="clr-namespace:WpfApp6.Style">       <multiValueConverter:ButtonMultiValueConverter x:Key="buttonMultiValueConverter" /> </ResourceDictionary>

　　

View里引用刚刚加的资源字典，放在DataContext下面

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<UserControl.Resources>         <ResourceDictionary >             <ResourceDictionary.MergedDictionaries>                 <ResourceDictionary  Source="..\Style\MultiValueConverterResource.xaml"/>             </ResourceDictionary.MergedDictionaries>         </ResourceDictionary>     </UserControl.Resources>

　　

View事件改为

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<b:Interaction.Triggers>                 <b:EventTrigger EventName="Click" >                     <b:InvokeCommandAction Command="{Binding Button_Click3}" >                         <b:InvokeCommandAction.CommandParameter >                             <MultiBinding Converter="{StaticResource buttonMultiValueConverter}">                                 <Binding ElementName="button1" />                                 <Binding ElementName="button2" />                             </MultiBinding>                         </b:InvokeCommandAction.CommandParameter>                     </b:InvokeCommandAction>                 </b:EventTrigger>             </b:Interaction.Triggers>

　　多个参数就增加多个

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1	<Binding ElementName="button1" /><br><br><br>

ViewModel代码，可以看到param是前面你自定义的ButtonModel

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private ICommand button_Click3;         public ICommand Button_Click3         {             get             {                 if (button_Click3 == null)                 {                     button_Click3 = new BaseCommand((param) =>                     {                         ButtonModel buttons = param as ButtonModel;                         MessageBox.Show("button:" + buttons.btn1.Content.ToString() + "      button2:" + buttons.btn2.Content.ToString());                         //....                     });                 }                 return button_Click3;             }         }

　　运行效果