C # simple steps for using Delegation

C # simple steps for using Delegation

The delegate can be understood as the function pointer in C or C ++. Calling the delegate actually calls the delegate method.

The procedure for using delegation is as follows:

1. Define Delegation

// Define the delegate use keyword delegate
Private delegate void SetProgressBarValueDelegate (int value );

2. Declare Delegation

Private SetProgressBarValueDelegate setProgressBarValue;

3. instantiate the delegate

SetProgressBarValue = new SetProgressBarValueDelegate (SetProgressBarValue1 );

SetProgressBarValue1 is the name of the delegate method. The parameter type must be consistent with the delegate type. The prototype is as follows:

// Set progress bar 1
Private void SetProgressBarValue1 (int value)
{
PgProgressBar1.Value = value;
}

4. Delegated use:

SetProgressBarValueMethod (setProgressBarValue );

// Set the progress bar value
Private void SetProgressBarValueMethod (SetProgressBarValueDelegate setProgressBarValueDelegate)
{
For (int I = 1; I <= 100; I ++)
{
Application. DoEvents ();
Thread. Sleep (50 );
SetProgressBarValueDelegate (I );
}
}

/* This Command tells the system to continue processing other events on the user interface to avoid false positives.
* Equivalent to Visual Basic 6.0 DoEvents ()
* Processing events () in easy language ()*/
Application. DoEvents ();
/* This command is used to suspend a thread (parameter: millisecond)
* If it is used in the main thread, it will lead to a false death. You can only pause it to make it clearer */

Thread. Sleep (50 );

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