WPF MVVMToolkit框架学习 命令的CanExecute

演示一下：如果文本框有内容，按钮就可用，如果没有内容，按钮就禁用

 

后台代码

using Microsoft.Toolkit.Mvvm.ComponentModel;
using Microsoft.Toolkit.Mvvm.Input;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace MVVMToolkit框架学习.ViewModels
{
    internal class TestViewModel : ObservableObject
    {
        private string _name = string.Empty;

        private IRelayCommand _submitCommand = null;

        public string Name
        {
            get
            {
                return _name;
            }

            set
            {
                SetProperty(ref _name, value);
                //触发验证事件 可以写在全局验证中
                SumbmitCommand.NotifyCanExecuteChanged();
            }
        }

        public IRelayCommand SumbmitCommand
        {
            get
            {
                return _submitCommand;
            }

            set
            {
                _submitCommand = value;
            }
        }

        public TestViewModel()
        {
            SumbmitCommand = new RelayCommand(ShowYourInput, () =>
            {
                //验证逻辑
                return !string.IsNullOrWhiteSpace(Name);
            });
        }

        /// <summary>
        /// 
        /// </summary>
        private void ShowYourInput()
        {
            MessageBox.Show("你的输入：" + Name, "信息");
        }
    }
}

前台界面

<Window
    x:Class="MVVMToolkit框架学习.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:local="clr-namespace:MVVMToolkit框架学习"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="MainWindow"
    Width="800"
    Height="450"
    mc:Ignorable="d">
    <Grid>
        <StackPanel
            VerticalAlignment="Center"
            Orientation="Vertical">
            <StackPanel
                HorizontalAlignment="Center"
                VerticalAlignment="Center"
                Orientation="Horizontal">
                <TextBlock
                    VerticalAlignment="Center"
                    Text="请输入名字：" />
                <!--在每一次属性更改的时候都验证 也可在LostFocus的时候验证-->
                <TextBox
                    Width="250"
                    VerticalContentAlignment="Center"
                    BorderBrush="Black"
                    Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}" Cursor="IBeam" />
                
            </StackPanel>
            <Button
                Width="80"
                Margin="0,10,0,0"
                Command="{Binding SumbmitCommand}"
                CommandParameter="{Binding ElementName=parameter, Path=Text}"
                Content="提交" Cursor="Hand" />
        </StackPanel>
    </Grid>
</Window>