C # asynchronous multithreading (access to the main program-controlled component)

In the case of multiple threads, other threads cannot directly call controls on the main thread. They can only call controls on the main thread through proxies.

1. Define Delegation
// Delegate statement for executing the task (solving the long task death false)
Delegate void RunTaskDelegate (int seconds );
// Display the delegate Declaration of the progress bar (cross-thread Call Control)
Delegate void ShowProgressDelegate (int totalStep, int currentStep );
2. Definition Method
Private void ShowProgress (int totalStep, int currentStep)
{
ProgressBar1.Maximum = totalStep;
ProgressBar1.Value = currentStep;
}
3. Define a thread
Private void RunTask (int seconds)
{
ShowProgressDelegate showProgress = new ShowProgressDelegate (ShowProgress );
For (int I = 0; I <seconds * 4; I ++)
{
Thread. Sleep (250 );
// Call the delegate that displays the progress bar in the basic window
This. Invoke (showProgress, new object [] {seconds * 4, I + 1 });
}
}
4. Execute
RunTaskDelegate runTask = new RunTaskDelegate (RunTask );
// Call the task delegate Asynchronously
RunTask. BeginInvoke (20, null, null );