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Questions tagged [invokerequired]

InvokeRequired refers to the .NET WinForms Control.InvokeRequired method, which needs to be checked before UI updates are made.

In .NET WinForms Control.InvokeRequired needs to be checked before UI updates are made.

It will be True when the handle has been created and the current thread is not the thread on which the control was created.

When it is True, you need to perform the UI update using a delegate call through Control.Invoke which will marshal the delegate onto the UI thread.

MSDN link - Note that other frameworks can implement this concept using the System.ComponentModel.ISynchronizeInvoke interface (though something is still needed to actually marshal the calls back to another thread).

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Automating the InvokeRequired code pattern

I have become painfully aware of just how often one needs to write the following code pattern in event-driven GUI code, where private void DoGUISwitch() { // cruisin for a bruisin' through exception city object1.Visible = true; …
Tom Corelis
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Cleaning up code littered with InvokeRequired

I know that when manipulating UI controls from any non-UI thread, you must marshal your calls to the UI thread to avoid issues. The general consensus is that you should use test InvokeRequired, and if true, use .Invoke to perform the…
Erik Forbes
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What's wrong with calling Invoke, regardless of InvokeRequired?

I've seen the common setup for cross threading access to a GUI control, such as discussed here: Shortest way to write a thread-safe access method to a windows forms control All the web hits I found describe a similar thing. However, why do we need…
MattH
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InvokeRequired in wpf

I used this function in a Windows forms application: delegate void ParametrizedMethodInvoker5(int arg); private void log_left_accs(int arg) { if (InvokeRequired) { Invoke(new ParametrizedMethodInvoker5(log_left_accs), arg); …
oehgr
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Isn't blindly using InvokeRequired just bad practice?

I am a novice programmer so I could be completely mistaken here, but this issue bugs me more then it should. This is actually a follow-up from this question. The accepted answer was, that you have to call InvokeRequired in order to avoid some…
Jordy
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Run code on UI thread without control object present

I currently trying to write a component where some parts of it should run on the UI thread (explanation would be to long). So the easiest way would be to pass a control to it, and use InvokeRequired/Invoke on it. But I don't think that it is a good…
Martin Moser
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InvokeRequired and ToolStripStatusLabel

In my application I have class that is responsible for all database actions. It is called from main class and uses delegates to call methods after action is complete. Because it is asynchronous I must use invoke on my GUI, so I've created a simple…
Misiu
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how to use Invoke method in a file of extensions/methods?

Well, I'm writing a file of extensions/method useful to strings,label,linklabels,class etc. but, I have a problem. I have an showMessage() method that change the Text of label, works fine. But I decide to do that works with thread execution, then I…
The Mask
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InvokeRequired of Form == false and InvokeRequired of contained control == true

how is it possible? I have windows Form control, derived from System.Windows.Forms.Form with WebBrowser control contained in this form. Webbrowser object instance is created in constructor of form (in InitializeComponent() method). Then in…
Dmitrii Lobanov
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Fire event from Async component in UI thread

I'm building a non-visual component in .Net 2.0. This component uses an asynchronous socket (BeginReceive, EndReceive etc). Asynchronous callbacks are called in the context of a worker thread created by the runtime. The component user shouldn't have…
ComponentBuilder
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SynchronizationContext and InvokeRequired

I have been looking all over for an answer to this question, but can't seem to find a satisfactory answer. Maybe someone here can enlighten me. I have a descendent of BindingList that stores a reference to a SynchronizationContext object in…
Dan
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Interview Question: When Control.InvokeRequired do you use Control.Invoke or Control.BeginInvoke?

I have had recently one of those really bad interviews, where they play good cop/bad cop with you. Whatever I replied wasn't good enough for one of them and my confidence was shrinking minute by minute. His final question that really confused me was…
Houman
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BeginInvoke is blocking the UI, whereas Invoke is not. Why?

I am confused with scenario which I have encountered with cross thread access. Here is what I am trying to do: Main UI thread - menu item click I create a background worker and run it asynchronously private void actionSubMenuItem_Click(object…
Nagaraj Tantri
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.NET Invoke Process Flow

I see/use some form or fashion of the code all the time: public void method1(Object sender, EventArgs args) { if(dataGridView1.InvokeRequired) dataGridView1.Invoke(new EventHandler(method1), null); else // Do something to…
poy
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Stackoverflow error while checking InvokeRequired

I'm getting a stackverflow error while executing InvokeRequired. System.StackOverflowException was unhandled How to fix it? There is no info i View Details. FIXED VERSION: public DialogResult ShowMessage(string msg, string caption,…
Hooch
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