public class Walterlv { // 省略了此命令的初始化。 public WalterlvCommand WalterlvCommand { get; } } public class WalterlvCommand : ICommand { public bool SomeFlag { get; set; } bool ICommand.CanExecute(object parameter) { // 判断命令的可用性。 return SomeFlag; } void ICommand.Execute(obj...
昨天在项目中遇到一个问题,按钮bind了Command后,利用CanExecute控制它的是否可点击。结果却在初始化viewmodel的时候执行了一次CanExecute,之后一直不触发,按钮的可用性状态也一直不改变。 publicDelegateCommand NewCommand {get;set; }publicDelegateCommand CheckCommand {get;set; } 看了半天,也没看出啥原因,以为是控件的...
昨天在项目中遇到一个问题,按钮bind了Command后,利用CanExecute控制它的是否可点击。结果却在初始化viewmodel的时候执行了一次CanExecute,之后一直不触发,按钮的可用性状态也一直不改变。 image.png <pre> public DelegateCommand NewCommand { get; set; } public DelegateCommand CheckCommand { get; set; } </pre> ...
对于ICommand的绑定,WPF内部会订阅CanExecuteChanged事件,当对应的ICommand实现产生通知时调用CanExecute函数确认是否需要更新控件状态。调用Delegate的GetInvocationList函数发现WPF 3.0返回的Target是对应的控件(比如Button),WPF 4.0则返回CanExecuteChangedEventManager类型。在CanExecuteChangedEventManager内部它需要使用sender关联Weak...
ICommand CanExecute() not working ICommand.CanExecute in MVVM Image border Image doesn't change when ImageSource changed Image in button not showing up when execution Image is not showing in runtime. Image Quality WPF Image Refresh problem Image shows during design time but not during runtime ...
CanExecuteCommand = null; public event EventHandler CanExecuteChanged; public bool CanExecute...ICommand接口中的Execute()方法用于命令的执行,CanExecute()方法用于指示当前命令在目标元素上是否可用,当这种可用性发生改变时便会触发接口中的CanExecuteChanged事件...InitializeComponent(); this.DataContext = new Stude...
Command是與CommandBinding建立關聯的命令。 附加到PreviewExecuted和Executed事件的事件處理常式會實作命令邏輯。 附加到PreviewCanExecute和CanExecute事件的事件處理常式會判斷命令是否可以在目前命令目標上執行。 下列範例將示範如何在應用程式的根目錄Window上建立CommandBinding。CommandBinding會將Open命令與Executed和CanExecute...
}voidOpenCmdCanExecute(objectsender, CanExecuteRoutedEventArgs e){ e.CanExecute =true; } 最後,會在應用程式的根CommandBinding上建立Window,將路由的事件處理常式與Open命令建立關聯。 XAML複製 <Window.CommandBindings><CommandBindingCommand="ApplicationCommands.Open"Executed="OpenCmdExecu...
CommandParameter invalidates CanExecute Ignore NotImplementedException from ITaskbarList lindexi Fix the stream do not be closed in ImageSourceTypeConverter Fix GetStreamCore in ContentFilePart Fix create BitmapDecoder with async file stream. Using theClonemethod to fast clone the array in StylusPoint ...
The CAL includes new commands such as the DelegateCommand<T>, which allows you to specify the two delegates for the Execute and CanExecute methods in the constructor. Using this command allows you to wire up views without having to delegate through methods defined in the view itself and wi...