MVVM通过Command 绑定 关闭窗体
View:
<Button Name="btnExit" Command="{Binding ExitCommand}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Window}}}" IsDefault="True" Style="{StaticResource ButtonBackgroundChanged}" Foreground="White" Margin="10,0,20,0">关 闭</Button>
<Controls:MetroWindow x:Class="ETRIMP_CustomsDeclarationWPF.WPF_CustomsDeclarationShow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" ShowSystemMenuOnRightClick="False"
xmlns:viewModel="clr-namespace:ETRIMP_CustomsDeclarationWPF.ViewModel">
<Window.DataContext>
<viewModel:CustomsDeclarationShowViewModel/>
</Window.DataContext>
这里注意页面设置DataContext,指定ViewModel路径:
xmlns:viewModel="clr-namespace:ETRIMP_CustomsDeclarationWPF.ViewModel"
ViewModel:
public ICommand ExitCommand
{
get { return new RelayCommand<Window>(wd =>
{
if (wd != null)
{
wd.Close();
}
});}
}
RelayCommand:
/// <summary>
/// A command whose sole purpose is to relay its functionality to other objects by invoking delegates. The default return value for the CanExecute method is 'true'.
/// </summary>
public class RelayCommand<T> : ICommand
{
#region Declarations
readonly Predicate<T> _canExecute;
readonly Action<T> _execute;
#endregion
#region Constructors
/// <summary>
/// Initializes a new instance of the <see cref="RelayCommand<T>"/> class and the command can always be executed.
/// </summary>
/// <param name="execute">The execution logic.</param>
public RelayCommand(Action<T> execute)
: this(execute, null)
{
}
/// <summary>
/// Initializes a new instance of the <see cref="RelayCommand<T>"/> class.
/// </summary>
/// <param name="execute">The execution logic.</param>
/// <param name="canExecute">The execution status logic.</param>
public RelayCommand(Action<T> execute, Predicate<T> canExecute)
{
if (execute == null)
throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
#endregion
#region ICommand Members
public event EventHandler CanExecuteChanged
{
add
{
if (_canExecute != null)
CommandManager.RequerySuggested += value;
}
remove
{
if (_canExecute != null)
CommandManager.RequerySuggested -= value;
}
}
[DebuggerStepThrough]
public Boolean CanExecute(Object parameter)
{
return _canExecute == null ? true : _canExecute((T)parameter);
}
public void Execute(Object parameter)
{
_execute((T)parameter);
}
#endregion
}
/// <summary>
/// A command whose sole purpose is to relay its functionality to other objects by invoking delegates. The default return value for the CanExecute method is 'true'.
/// </summary>
public class RelayCommand : ICommand
{
#region Declarations
readonly Func<Boolean> _canExecute;
readonly Action _execute;
#endregion
#region Constructors
/// <summary>
/// Initializes a new instance of the <see cref="RelayCommand<T>"/> class and the command can always be executed.
/// </summary>
/// <param name="execute">The execution logic.</param>
public RelayCommand(Action execute)
: this(execute, null)
{
}
/// <summary>
/// Initializes a new instance of the <see cref="RelayCommand<T>"/> class.
/// </summary>
/// <param name="execute">The execution logic.</param>
/// <param name="canExecute">The execution status logic.</param>
public RelayCommand(Action execute, Func<Boolean> canExecute)
{
if (execute == null)
throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
#endregion
#region ICommand Members
public event EventHandler CanExecuteChanged
{
add
{
if (_canExecute != null)
CommandManager.RequerySuggested += value;
}
remove
{
if (_canExecute != null)
CommandManager.RequerySuggested -= value;
}
}
[DebuggerStepThrough]
public Boolean CanExecute(Object parameter)
{
return _canExecute == null ? true : _canExecute();
}
public void Execute(Object parameter)
{
_execute();
}
#endregion
}
我这种写法需要利用上面这个ICommand实现类.