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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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correct access of a windows form inside backgroundworker thread

I have a winforms app, and I need to access the Handle property of a main form, inside a Backgroundworker thread. I have made a thread safe method that calls the main form with InvokeRequired. My question is - why do I still get…
Amc_rtty
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I would like to remove it from the checkout page but It has required attribute how to remove it?

This is inside the checkout.page.blade I would like to remove the account creation form from the checkout page but the e-mail and password section has required attribute and it shows it is required at the front end even if i remove this part from…
Э. Бумбаяр
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InvokeRequired property missing in VS2017/2017

I'm creating a Windows Forms program and in VS2017/2019, the intellisense doesn't prompt InvokeRequired property for no matter TextBox control or the form itself. When compiling, the error:'InvokeRequired' is not a member of Textbox was generated by…
Alex Xinrun Du
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Is there a way to implement or use Invokes/Threadings in Xamarin?

First of all: I'm very new to Xamarin, so this might sound quite stupid. I need to "rewrite" a c#-programm to Xamarin (as in: I programmed an Computerprogramm and I now have to write an android-app for it. I'm using Android-App(Xamarin).). So far,…
Kaija
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C# Lambda Method Does Not Throw Exception when Accessing Winforms UI Control

In the example below, when the Tag1_changed and Tag2_changed methods are invoked, they require the form to be invoked to update a control or else an exception is thrown. However, when using the lambda method for the callback parameter,…
Steve B.
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Fixing thread safe calls from backgroundWorker

using System; using System.ComponentModel; using System.Net; using System.Windows.Forms; using Ionic.Zip; namespace downloader { public partial class GUI : Form { string desktop =…
Kyle
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InvokeRequired to checkbox

I just need to create a function to checkbox that will return the current value of checkbox. I wrote : private void Checkbox_check() { if (checkBox1.InvokeRequired) return (int)checkBox1.Invoke(new…
Adamszsz
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EndInvoke() does not return (loop? deadlock?)

I'm just playing around a bit with this neat code from Codeproject There is a safe invocation method for controls: public static TResult SafeInvoke(this T isi, Func call) where T : ISynchronizeInvoke { if…
stev-e
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Control.BeginInvoke not working with TextBox.AppendText, Cross Threading

I want to expose a method to update a text box with messages as a status log. I would like to use the AppendText method but I'm experiencing a strange multi threading issue when using it. I'm able to append new messages by concatenation just fine.…
Jon
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Control.InvokeRequired changing throughout a method

Look at these screenshots. First shows a breakpoint in my code and shows current value of InvokeRequired. Seconds screenshot shows value of InvokeRequired after pressing F10 (step over) one time in debugger (IF statement content is not entered,…
Mateusz Krzaczek
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C# Questions regarding Invoke, Invokerequired & Multithreading

I have 2 forms running on different threads. Form2 will generate a string, send it back to form1 and update the richtextbox in form1. I got the code from my friend but I don't understand a part of it. Could you please explain to me why do we need…
Louis Tran
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Wanted but not invoke: Mockito test

I have a problem. I don't understand why mockito go in exception. RecordWriter write a Record into the file. I want verify if it write or not. I implemented another function and i tried to mock(OutputStream.class), but the result is the same. My…
Vincenzo Santoliquido
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How to access richtextbox via different thread

Hey guys my question is how can I access (update/read) richtextbox in a thread. I just created a very simple code for you to understand what I am doing. I searched some articles on internet mentioned about invoke, delegate or backgroundworker, hope…
Dogemike
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Invoking a control from backgroundworker stops with no error

I'm running a BackgroundWorker which suppose to update my UserControl. I tried Invoking after checking InvokeRequired property: private void bgwHighlightText_DoWork(object sender, DoWorkEventArgs e) { tmpRich.SelectedRtf = myRtf; if…
Ghasem
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form.Invoke(delegate) Cannot access a disposed object. .net

Enviroment: vb.net visual studio 10 - win forms The Error: {"Cannot access a disposed object. Object name:'frmInfo'."} StackTrace: at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean…
Jer WasHere
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