如何使用 WPF（后端）在按钮控件中添加命令

Question

如何使用后端代码向WPF中的按钮控件添加命令？

Answer 1

在代码隐藏中添加命令的简单示例

class SomeCommand : ICommand
{
    public event EventHandler CanExecuteChanged;

    public bool CanExecute(object parameter)
    {
        return true;
    }

    public void Execute(object parameter)
    {
        MessageBox.Show("From command");
    }
}

并且在 InitializeComponent() 之后的构造函数中；

        var btnCompare = new Button();
        btnCompare.Content = "Compare";
        btnCompare.Command = new SomeCommand();

        grid.Children.Add(btnCompare);

更新

正如我从您的评论中了解到的，您想将参数传递给命令，它应该根据某些条件更改 ICommand.CanExecute 方法的 return 值。这可以通过将委托作为参数传递并在命令中实现 CanExecuteChanged 事件作为 CommandManager.RequerySuggested 事件的包装器来实现。命令应触发 CanExecuteChanged 以通知框架，CanExecute 方法的 return 值已更改。

通常 CommandManager.RequerySuggested 每次用户与应用程序界面交互时都会触发，对于其他情况，您可以调用 CommandManager.InvalidateRequerySuggested() 静态方法。下面是说明该方法的代码。

XAML

<Grid Name="grid">
    <Grid.RowDefinitions>
        <RowDefinition Height="50"/>
        <RowDefinition />
        <RowDefinition />
    </Grid.RowDefinitions>
    <CheckBox Content="Bool value is true" Click="checkBoxBool_Click" IsChecked="True"/>
</Grid>

C#

class SomeCommand : ICommand
{
    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

    public bool CanExecute(object parameter)
    {
        Func<bool> isTrue = (Func<bool>)parameter;
        return isTrue != null && isTrue();
    }

    public void Execute(object parameter)
    {
        MessageBox.Show("From command");
    }
}

...

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        var btnCompare = new Button();
        btnCompare.Content = "Compare";

        btnCompare.CommandParameter = new Func<bool> (() => GetBoolValue());
        btnCompare.Command = new SomeCommand();

        btnCompare.SetValue(Grid.RowProperty, 1);

        grid.Children.Add(btnCompare);
    }

    private bool _boolValue = true;
    private bool GetBoolValue()
    {
        return _boolValue;
    }

    private void checkBoxBool_Click(object sender, RoutedEventArgs e)
    {
        _boolValue = (e.Source as CheckBox).IsChecked == true;

    }
}

如何使用 WPF（后端）在按钮控件中添加命令

How to add command in button control with WPF (Backend)

wpf

controls

command