使用 MVVM 在 WPF 中绑定命令 [英] Bind command in WPF using MVVM

问题描述

我正在学习 MVVM 和 WPF.我的项目中有一个 xaml 文件，并且在后面的代码中有一个简单的点击事件处理程序.

I am learning MVVM and WPF. I have a xaml file in my project and which has a simple click event handler in the code behind.

现在我想在 MVVM 中做同样的事情.看了很多文章，也在sof上看了很多答案.但仍然无法做到这一点.

Now I want to do the same in MVVM. I read a lot of articles and also read many answers in sof. But still unable to do this.

谁能举一个简单的例子，在MVVM中完成一个按钮点击事件.

Can anyone please give a simple example in which a button click event is done in MVVM.

编辑

<Window x:Class="WhiteBalance.BaseCalWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:uc="clr-namespace:NumberUpDownControl;assembly=NumberUpDownControl"
        xmlns:viewn="clr-namespace:WhiteBalance.ViewModels"
        Title="RefImgSettingWindow"  Height="900" Width="1000" ResizeMode="NoResize" 
        BorderThickness="4">
    <Window.Resources>
        <viewn:DashBoardViewModel x:Key="demokey"></viewn:DashBoardViewModel>
    </Window.Resources>
    <Grid x:Name="gdParent" DataContext="{StaticResource demokey}">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="490" />
            <ColumnDefinition Width="488*" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="300" />
            <RowDefinition Height="300" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <StackPanel Grid.Row="0" Grid.Column="0">
            <Label Content="{Binding Path=NAME,Mode=TwoWay}" Height="28" Name="lblTest" />
            <Button Content="Capture" Height="23" Name="btnCapture" Width="75" Command="{Binding Path=SaveCommand}"
                             Canvas.Left="94" Canvas.Top="254" />

        </StackPanel>
    </Grid>
</Window>

namespace WhiteBalance.ViewModels
{
    public class DashBoardViewModel: ObservableObject
    {
        private string _name = "dsqdasd";

        public string NAME
        {
            get { return _name; }
            set { _name = value; }
        }

        public ICommand SaveCommand
        {
            get;
            set;
        }

        private bool CanExecuteSaveCommand()
        {
            return true;    // !string.IsNullOrEmpty(LastName);
        }

        private void CreateSaveCommand()
        {
            SaveCommand = new RelayCommand(SaveExecute, CanExecuteSaveCommand);
        }

        public void SaveExecute()
        {
            //Person.Save(_newPerson);
            NAME = "Changed Name";
        }

        public DashBoardViewModel()
        {
            //objModel.TestText = "This will change";
            NAME = "TestName";
        }
    }
}

提前致谢.

推荐答案

您可以绑定 Command 按钮属性到任何返回 ICommand.Prism 实现了一个非常方便的命令 DelegateCommand 非常容易使用 (这里是一个仿制品):

You can bind the Command property of the button to any property that returns ICommand. Prism implements a nice convenient command called DelegateCommand that is very easy to use (here is a knock-off of it):

public ICommand MyButtonClickCommand 
{
    get { return new DelegateCommand<object>(FuncToCall, FuncToEvaluate); }
}

private void FuncToCall(object context)
{
    //this is called when the button is clicked
}

private bool FuncToEvaluate(object context)
{
    //this is called to evaluate whether FuncToCall can be called
    //for example you can return true or false based on some validation logic
    return true;
}



<Button x:Name="myButton" Command="{Binding MyButtonClickCommand}" />

CodeProject 示例 如何使用命令在 WPF 中有一个非常相似的示例，其中包含您可以轻松完成的代码.之前的 Stack Overflow 问题有一个使用静态绑定到的 RoutedCommands 的示例:如何将关闭命令绑定到按钮和如何将 WPF 按钮绑定到 ViewModelBase 中的命令? 有一个稍微高级的示例.

The CodeProject example How to use Commands in WPF has a very similar example with code that you can easily work through. The previous Stack Overflow question has an example using RoutedCommands that are statically bound to: How to bind Close command to a button, and How to bind WPF button to a command in ViewModelBase? has a slightly more advanced example.

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