WPF 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>