WPF 自定义Command

无参Command:

internal class DelegateCommand : ICommand
    {
        private readonly Action _execute;
        private readonly Func<bool> _canExecute;

        public DelegateCommand(Action execute) : this(execute, null) { }
        public DelegateCommand(Action execute, Func<bool> canExecute)
        {
            _execute = execute ?? throw new ArgumentNullException(nameof(execute));
            _canExecute = canExecute;
        }

        public void Execute(object parameter)
        {
            _execute();
        }
        public bool CanExecute(object parameter)
        {
            if (_canExecute == null) return true;
            return _canExecute();
        }


        public event EventHandler CanExecuteChanged
        {
            add => CommandManager.RequerySuggested += value;
            remove => CommandManager.RequerySuggested -= value;
        }
    }

有参Command:

    internal class DelegateCommand<T> : ICommand
    {
        private readonly Action<T> _execute;
        private readonly Func<bool> _canExecute;

        public DelegateCommand(Action<T> execute) : this(execute, null) { }
        public DelegateCommand(Action<T> execute, Func<bool> canExecute)
        {
            _execute = execute ?? throw new ArgumentNullException(nameof(execute));
            _canExecute = canExecute;
        }

        public void Execute(object parameter)
        {
            _execute((T)parameter);
        }
        public bool CanExecute(object parameter)
        {
            if (_canExecute == null) return true;
            return _canExecute();
        }


        public event EventHandler CanExecuteChanged
        {
            add => CommandManager.RequerySuggested += value;
            remove => CommandManager.RequerySuggested -= value;
        }
    }

在viewmodel中，定义一个Command属性

Command=new DelegateCommand<string> (searchText=>{
　　//添加逻辑
});

然后绑定即可。

<Window x:Class="WpfApp21.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:viewModels="clr-namespace:WpfApp21.ViewModels"
        xmlns:local="clr-namespace:WpfApp21"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.DataContext>
        <viewModels:SearchWordViewModel/>
    </Window.DataContext>
    <StackPanel>
        <TextBox x:Name="InputTextBox"></TextBox>
        <Button Command="{Binding SearchCommand}" CommandParameter="{Binding ElementName=InputTextBox,Path=Text}"></Button>
    </StackPanel>
</Window>