C#WPF界面MVVM框架下异步命令的启动和停止及绑定
2024-01-02 17:40:37
框架采用CommunityToolkit.Mvvm,界面如下
?View的XAML代码
<Window x:Class="WpfApp6.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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp6"
xmlns:FF="clr-namespace:WpfApp6"
mc:Ignorable="d"
Title="MainWindow" Height="200" Width="300">
<Grid>
<StackPanel Height="200" Background="AliceBlue" Orientation="Vertical" Width="300" >
<TextBlock Name="Lb" Text="{Binding myMessage.Message,Mode=OneWay}" Height="40" Background="LightCoral"/>
<Button x:Name="btnclick" Content="Run" Background="Gold" Command="{Binding ExecCommand }" Height="40" BorderThickness="3,2,3,2"/>
<CheckBox Content="按钮状态" IsChecked="{Binding ExecCommand.IsRunning,Mode=OneWay,UpdateSourceTrigger=PropertyChanged}"/>
<Button x:Name="btnCancelclick" Content="Stop" Background="Gold" Command="{Binding CancleExecCommand }" Height="40" BorderThickness="3,2,3,2"/>
</StackPanel>
</Grid>
</Window>
ViewModel如下
// Ignore Spelling: App
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using CommunityToolkit.Mvvm.Messaging;
using System;
using System.Threading;
using System.Threading.Tasks;
namespace WpfApp6
{
public class MainWinViewModel : ObservableRecipient, IRecipient<MyMessage>
{
public MainWinViewModel()
{
this.IsActive = true;
ExecCommand = new AsyncRelayCommand(ExecAsync);
CancleExecCommand = new RelayCommand(ExecCommand.Cancel);
}
public void Receive(MyMessage message)
{
myMessage.Message = $"Num={message.Id},Str={message.Message}";
}
public MyMessage myMessage { get; set; }=new MyMessage() { Id =1, Message="原始信息"};
public AsyncRelayCommand ExecCommand { get; }
private async Task ExecAsync( CancellationToken cancellationToken)
{
while (true)
{
if (cancellationToken.IsCancellationRequested)
return;
await Task.Delay(1);
WeakReferenceMessenger.Default.Send(new MyMessage { Id = 123, Message = DateTime.Now.ToString() });
}
}
public RelayCommand CancleExecCommand { get; set; }
}
}
Model如下:
using CommunityToolkit.Mvvm.ComponentModel;
namespace WpfApp6
{
public partial class MyMessage : ObservableObject
{
[ObservableProperty]
private int? id;
[ObservableProperty]
private string? message;
}
}
ViewModel和View的连接:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainWinViewModel();//建立viewmodel和view的联系
}
}
文章来源:https://blog.csdn.net/lovelyangel2008/article/details/135344745
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