C# 如何在WPF 4.5中对按钮单击事件进行标记扩展?
我想创建MarkupExtension以支持按钮单击事件。我有一篇文章要给PreviewKeyDown。我试图修改它的点击,但无法这样做,因为它抛出了一个异常C# 如何在WPF 4.5中对按钮单击事件进行标记扩展?,c#,.net,wpf,.net-4.5,C#,.net,Wpf,.net 4.5,我想创建MarkupExtension以支持按钮单击事件。我有一篇文章要给PreviewKeyDown。我试图修改它的点击,但无法这样做,因为它抛出了一个异常 请建议如何实现此操作。看起来它试图将MethodInfo转换为EventInfo,返回的目标属性可能是MethodInfo或EventInfo,您必须在创建委托之前检查此属性 试试这个 public class Call : MarkupExtension { public string ActionNam
请建议如何实现此操作。看起来它试图将
MethodInfo
转换为EventInfo
,返回的目标属性可能是MethodInfo
或EventInfo
,您必须在创建委托之前检查此属性
试试这个
public class Call : MarkupExtension
{
public string ActionName { get; set; }
public Call(string actionName) { ActionName = actionName; }
public override object ProvideValue(IServiceProvider serviceProvider)
{
IProvideValueTarget targetProvider = serviceProvider
.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
if (targetProvider == null)
throw new InvalidOperationException(@"The CallAction extension
can't retrieved the IProvideValueTarget service.");
var target = targetProvider.TargetObject as FrameworkElement;
if (target == null)
throw new InvalidOperationException(@"The CallAction extension
can only be used on a FrameworkElement.");
if (targetProvider.TargetProperty is MethodInfo)
{
var targetEventAddMethod = targetProvider.TargetProperty as MethodInfo;
if (targetEventAddMethod != null)
{
ParameterInfo[] pars = targetEventAddMethod.GetParameters();
Type delegateType = pars[1].ParameterType;
MethodInfo methodInfo = this.GetType().GetMethod("MyProxyHandler", BindingFlags.NonPublic | BindingFlags.Instance);
return Delegate.CreateDelegate(delegateType, this, methodInfo); ;
}
}
else if (targetProvider.TargetProperty is EventInfo)
{
var targetEventInfo = targetProvider.TargetProperty as EventInfo;
if (targetEventInfo != null)
{
Type delegateType = targetEventInfo.EventHandlerType;
MethodInfo methodInfo = this.GetType().GetMethod("MyProxyHandler", BindingFlags.NonPublic | BindingFlags.Instance);
return Delegate.CreateDelegate(delegateType, this, methodInfo);
}
}
return null;
}
void MyProxyHandler(object sender, EventArgs e)
{
FrameworkElement target = sender as FrameworkElement;
if (target == null) return;
var dataContext = target.DataContext;
if (dataContext == null) return;
//get the method on the datacontext from its name
MethodInfo methodInfo = dataContext.GetType()
.GetMethod(ActionName, BindingFlags.Public | BindingFlags.Instance);
methodInfo.Invoke(dataContext, null);
}
}