WPF 自定义Command

无参Command:

 1 internal class DelegateCommand : ICommand
 2     {
 3         private readonly Action _execute;
 4         private readonly Func<bool> _canExecute;
 5 
 6         public DelegateCommand(Action execute) : this(execute, null) { }
 7         public DelegateCommand(Action execute, Func<bool> canExecute)
 8         {
 9             _execute = execute ?? throw new ArgumentNullException(nameof(execute));
10             _canExecute = canExecute;
11         }
12 
13         public void Execute(object parameter)
14         {
15             _execute();
16         }
17         public bool CanExecute(object parameter)
18         {
19             if (_canExecute == null) return true;
20             return _canExecute();
21         }
22 
23 
24         public event EventHandler CanExecuteChanged
25         {
26             add => CommandManager.RequerySuggested += value;
27             remove => CommandManager.RequerySuggested -= value;
28         }
29     }
View Code

有参Command:

 1     internal class DelegateCommand<T> : ICommand
 2     {
 3         private readonly Action<T> _execute;
 4         private readonly Func<bool> _canExecute;
 5 
 6         public DelegateCommand(Action<T> execute) : this(execute, null) { }
 7         public DelegateCommand(Action<T> execute, Func<bool> canExecute)
 8         {
 9             _execute = execute ?? throw new ArgumentNullException(nameof(execute));
10             _canExecute = canExecute;
11         }
12 
13         public void Execute(object parameter)
14         {
15             _execute((T)parameter);
16         }
17         public bool CanExecute(object parameter)
18         {
19             if (_canExecute == null) return true;
20             return _canExecute();
21         }
22 
23 
24         public event EventHandler CanExecuteChanged
25         {
26             add => CommandManager.RequerySuggested += value;
27             remove => CommandManager.RequerySuggested -= value;
28         }
29     }
View Code

在viewmodel中,定义一个Command属性

1 Command=new DelegateCommand<string> (searchText=>{
2   //添加逻辑
3 });

然后绑定即可。

 1 <Window x:Class="WpfApp21.MainWindow"
 2         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 3         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 4         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
 5         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 6         xmlns:viewModels="clr-namespace:WpfApp21.ViewModels"
 7         xmlns:local="clr-namespace:WpfApp21"
 8         mc:Ignorable="d"
 9         Title="MainWindow" Height="450" Width="800">
10     <Window.DataContext>
11         <viewModels:SearchWordViewModel/>
12     </Window.DataContext>
13     <StackPanel>
14         <TextBox x:Name="InputTextBox"></TextBox>
15         <Button Command="{Binding SearchCommand}" CommandParameter="{Binding ElementName=InputTextBox,Path=Text}"></Button>
16     </StackPanel>
17 </Window>

 

posted @ 2017-09-14 22:42 唐宋元明清2188 阅读(...) 评论(...) 编辑 收藏