You also could use an extension method and lambdas to make your code much cleaner. using System.ComponentModel; public static class ISynchronizeInvokeExtensions { public static void InvokeEx<T>(this T @this, Action<T> action) where T : ISynchronizeInvoke { if (@this.InvokeRequired) { @this.Invoke(action, new object[] { @this }); } else { action(@this); } } } So now you can … Read more
You have to Invoke() so you can wait for the function to return and obtain its return value. You’ll also need another delegate type. This ought to work: public static string readControlText(Control varControl) { if (varControl.InvokeRequired) { return (string)varControl.Invoke( new Func<String>(() => readControlText(varControl)) ); } else { string varText = varControl.Text; return varText; } }
From non-UI threads we can’t touch the UI – very bad things can happen, since controls have thread affinity. So from a non-UI thread we must (at a minumum) call Invoke or BeginInvoke. For UI-threads, however – we don’t want to call Invoke lots of time; the issue is that if you are already on … Read more
When you use Dispatcher.BeginInvoke it means that it schedules the given action for execution in the UI thread at a later point in time, and then returns control to allow the current thread to continue executing. Invoke blocks the caller until the scheduled action finishes. When you use BeginInvoke your loop is going to run … Read more
Well how about this: public static class ControlHelpers { public static void InvokeIfRequired<T>(this T control, Action<T> action) where T : ISynchronizeInvoke { if (control.InvokeRequired) { control.Invoke(new Action(() => action(control)), null); } else { action(control); } } } Use it like this: private void UpdateSummary(string text) { summary.InvokeIfRequired(s => { s.Text = text }); }
According to MSDN, to use the default parameter you should pass Type.Missing. If your constructor has three optional arguments then instead of passing an empty object array you’d pass a three element object array where each element’s value is Type.Missing, e.g. type.GetParameterlessConstructor() .Invoke(BindingFlags.OptionalParamBinding | BindingFlags.InvokeMethod | BindingFlags.CreateInstance, null, new object[] { Type.Missing, Type.Missing, Type.Missing }, … Read more
Both are equally correct, but the documentation for Control.Invoke states that: The delegate can be an instance of EventHandler, in which case the sender parameter will contain this control, and the event parameter will contain EventArgs.Empty. The delegate can also be an instance of MethodInvoker, or any other delegate that takes a void parameter list. … Read more
Let’s say you want to call MyClass.myMethod(int x); Method m = MyClass.class.getDeclaredMethod(“myMethod”, Integer.TYPE); m.setAccessible(true); //if security settings allow this Object o = m.invoke(null, 23); //use null if the method is static
With Java 8+ and Lambda expressions With lambdas (available in Java 8+) we can do it as follows: class Test { public static void main(String[] args) throws Exception { Map<Character, Runnable> commands = new HashMap<>(); // Populate commands map commands.put(‘h’, () -> System.out.println(“Help”)); commands.put(‘t’, () -> System.out.println(“Teleport”)); // Invoke some command char cmd = ‘t’; … Read more
You can just call it as a normal function: function myfunction(param1, callbackfunction) { //do processing here callbackfunction(); } The only extra thing is to mention context. If you want to be able to use the this keyword within your callback, you’ll have to assign it. This is frequently desirable behaviour. For instance: function myfunction(param1, callbackfunction) … Read more