invoke

Why exceptions are not propagated by WPF Dispatcher.Invoke?

Here's my hypothetical example. I have a very simple WPF window with a one Button. The Button.Click event has a handler that goes like this. Action doit = () => { Action error = () => { throw new InvalidOperationException("test"); }; try { this.Dispatcher.Invoke(error, DispatcherPriority.Normal); } catch (Exception ...

return value from control.Invoke((MethodInvoker) delegate { /* ... */ }; I need some explainations.

What's the difference between #1 and #2: Code 1 (compiled ok): byte[] GetSomeBytes() { return (byte[])this.Invoke((MethodInvoker)delegate { GetBytes(); }); } byte[] GetBytes() { GetBytesForm gbf = new GetBytesForm(); if(gbf.ShowDialog() == DialogResult.OK) ...

Invoke or BeginInvoke cannot be called on a control until the window handle has been created.

Hi, I'm getting this error: Invoke or BeginInvoke cannot be called on a control until the window handle has been created. On these lines: m_SplashForm.Invoke( new SplashStatusChangedHandle(delegate(string str) { m_SplashInterface.SetStatusInfo(str); }), new object[] { value } ); I'...

Invoking Something Twice Leads To: "protected override void Dispose"

I have a function that helps me close forms without getting crossthread errors: public void OutsideClose(long Id) { MessageBox.Show(""); if (InvokeRequired) { Invoke(new Action<long>(OutsideClose), Id); } else { var asdf = ListForm.Find(a => a.Id == Id); ...

cross-thread operation even when executing on UI thread

I have a function which adds a control to a parent control which is called from threads different to the thread the controls were created on. This is how it goes: 1 delegate void AddControlToParentDelegate(Control child, Control parent); 2 private void addControlToParent(Control child, Control parent) { 3 if (parent...

Invoke With Two Parameters Of Different Variable Types?

How can I write an invoke method with two parameters of differing variable types? public void InsertStockPrice(double Value, string Company) { if (InvokeRequired) { Invoke(new Action<double>(InsertStockPrice), Value); // <- Not sure what to do here } else { //Do stu...

cross thread invoke compilation problem

Can anyone advise why this line of code would not compile? It generates CS1660 instead: s.run_button.Invoke((b) => { b.Enabled = false; }, new object[] { s.run_button }); Visual studio says: Cannot convert lambda expression to type 'System.Delegate' because it is not a delegate type ...

How to invoke generic lambda expressions?

private void ExecuteCommand(Expression<Func<bool>> command) { bool success = command.Compile().Invoke(); } private void Test() { ExecuteCommand(() => _gc.ChargeCancellation("")); } With this code, I got a NullReferenceException. ...

Silverlight - Opera 10 - JavaScript invoke

Hi, I have problems with invoking javaScript code on page with Opera 10 browser. JavaScript code on page: function CallMe(){ alert("It works!"); } And I am invoking this code with: HtmlPage.Window.Invoke("CallMe"); In all browsers except Opera this works great. In Opera I get error: "failed to invoke: CallMe" What am I doing ...

[C# windows form]When invoking a listview in a thread, other controls doesnt work

I am new to C#, I hope my description of the problem is readable. Here's my problem, I am developing a app for a win6.5 mobile. The App should have some memu items, one is 'scan', when clicked, it scans repeatedly the wifi access points nearby, and displays them on a listview. So i create a thread with a while loop for scanning every 10 ...

C# Winforms Threading: Closed Form Gets Invoked

The following code demonstrates my dilemma. The code creates a background thread which processes something, then Invokes the UI thread with the result. It may throw an exception if the background thread calls Invoke on the form after the form has closed. It checks IsHandleCreated before calling Invoke, but the form might close after the...

Would it make sense to have two GUI threads for two independent forms?

At work we've got a very CPU-intensive Windows Forms application. It's running on a server with 24 cores. As the Windows Forms model involves a single GUI thread processing a message pump, it seems that a rich, complex GUI is not making good use of the capabilities of the system. Am I wrong in saying this? So my coworkers were discussi...

Invoking android apk from another apk

I tried invoking an android apk (AA1) from another apk (BB1) by raising intent. But BB1 starts starts AA1 in its own process space and it does not use the existing running process of AA1. How can I achieve a. I want BB1 to use existing AA1 if it is already running. b. If it is not already there, it should invoke AA1 as an independent ap...

why is a captured variable not holding a reference to the instance of an object

As the code shows below, I'm creating a thread in a foreach loop and running them at a later time, however when I run the thread I get the "object reference not set to an instance of an object" error. I suspect this is a closure problem, but it seems like i'm doing everything i should be to avoid that here by creating a local copy of th...

Invoking the HREF attribute of a link with javascript using javascript!!!!

I never seen this before but you can invoke the HREF attribute of a link using javascript if the HREF contains javascript:;//code......; On my example below click on both links. they do the same thing even though they have different javascript in the HREF. for example: <script type="text/javascript"> function clickme(...

Getting an access to Idispatch member of idispatch interface

Hi people. I am a physicist. I am trying to work on Delphi with an imported activex control (ocx file). Let’s say there are 3 automation interfaces in the library: IGraph, IGraphAxes and IAxis. The structure of the library is such that: ===IGraph’s properties:=== Idispatch* IGraphAxes; ... //other members ===IGraphAxes’ properties:=== ...

Parameter count mismatch with Invoke?

The code block below results in the error: TargetParameterCountException was unhandled by user code. Parameter count mismatch. public void AddListViewItem(string[] Data) { if (InvokeRequired) { Invoke(new Action<string[]>(AddListViewItem), Data); } else { ListViewD...

What is the correct syntax for this usage of MethodInvoker?

The following code compiles and runs fine. void myInvokedMethod(string s) { Console.WriteLine(s); } void myInvoker() { Invoke(new MethodInvoker(delegate() { myInvokedMethod("one"); })); Invoke(new MethodInvoker(delegate { myInvokedMethod("two"); })); } When I call myInvoker, both calls to myInvokedMethod get through. W...

C#: deadlock when invoking the UI thread from a worker thread

Hi all, I have a deadlock when I invoke the UI thread from a worker thread. Indeed, the worker thread is blocked on the invoke line: return (ucAvancementTrtFamille)mInterfaceTraitement.Invoke(d, new object[] { psFamille }); The weird thing is that the UI Thread (which, correct me if I'm wrong, is the main thread) is idle. Is there a...

Retrieving property value from a form element in a thread-safe way

I use this method courtesy of casperOne to set property values on form elements if an invoke is required. static void SynchronizedInvoke(ISynchronizeInvoke sync, Action action) { // If the invoke is not required, then invoke here and get out. if (!sync.InvokeRequired) { // Execute action. action(); /...