C # Why multithreading control WinForm need to use a delegate?

C # (C # Training) Why does multi- threading control WinForm require a delegate? for example, I have a new thread A, in the a thread to the WinForm list control display data, I need to use a delegate function to implement.

Because WinForm is created by the master thread , you may have two threads accessing the same resource at the same time with another thread, which is prone to errors, such as a thread changing the color of the window to red, the B thread taking the window color, If these two threads happen to meet together, maybe a slightly before B, then is a b taken out of the red, if slightly later than the original color, and this and CPU busy, time slice of the rotation is related, is a random situation, then b out of the color is not reliable, so in order to avoid this situation using the delegation, The b thread sends a delegate to the A thread, which completes the color-fetching work by a thread, which guarantees the stability of the color-fetching work.

If you really want to access WinForm through another thread , you can add the window's constructor

Control.checkforillegalcrossthreadcalls = false;

This can block the error, but the recommendation is to use the delegate

This requires the use of a delegate.

You declare a delegate, and then you give the function of an interface to him.

You can just call this delegate on your thread.

　　C # try to write a multi- threaded problem (delegate, Invoke (), BeginInvoke ())

Using System;

Using System.Collections.Generic;

Using System.ComponentModel;

Using System.Data;

Using System.Drawing;

Using System.Text;

Using System.Windows.Forms;

Using System.Threading;

Using System.Diagnostics;

namespace _

{Public partial class Form1:form

{publicdelegatevoid del (string str);

Publicdelegatevoid Del1 (string str1);

Thread thread1,thread2;

Public Form1 ()

{InitializeComponent ();

} privatevoid button1_click (object sender, EventArgs e)

{this.thread1 = new Thread (new ThreadStart (THIS.SA));

This.thread1.Start ();

MessageBox.Show (this,);

this.button1.Enabled = false;

Gets the current thread good

int thread1id = Thread.CurrentThread.GetHashCode ();

String strthreadid = Convert.ToString (thread1id);

MessageBox.Show (This,strthreadid);

} privatevoid Progressset (string text)

{progressbar1.value = 0;

Progressbar1.maximum = 999999;

for (int i = 0; i < 999999; i++)

{progressbar1.value++;

} progressbar1.value = 0;

} privatevoid SA ()

{del Pro = new del (progressset);

This. Invoke (Pro, newobject[] {"Hello"});

} privatevoid button2_click (object sender, EventArgs e)

{this.thread2 = new Thread (THIS.SA1);

Thread2. Start ();

this.button2.Enabled = false;

Gets the current thread good

int thread2id = Thread.CurrentThread.GetHashCode ();

String strthreadid = Convert.ToString (thread2id);

MessageBox.Show (this, strthreadid);

} privatevoid SA1 ()

{//Other actions

For example, set the TextBox content of the interface

Del1 mi1 = new Del1 (Updatetextbox);

This. Invoke (MI1, newobject[] {"I am a text box"});

}//methods to update the interface

Privatevoid Updatetextbox (String str)

{//update

This.textBox1.Text = str;

} } }

C # Why multithreading control WinForm need to use a delegate?