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This article mainly introduces how to use delegate type to design custom events in C#. It is very detailed and has certain reference value. Friends who are interested must read it!

Design custom events using the delegate type

In C # programming, any Class except Method and Property can have its own Event. The steps to define and use custom events are as follows:

(1) define a delegate type outside Class to determine the interface of the event program

(2) inside Class, declare a public event variable with the type of delegate defined in the previous step

(3) trigger an event somewhere within a Method or Property

(4) use the + = operator to specify the event handler in the Client program

Example: / / define the Delegate type and restrict the parameters of the event program

Public delegate void MyEventHandler (object sender, long lineNumber); public class DataImports {/ / define new event NewLineRead public event MyEventHandler NewLineRead; public void ImportData () {long I = 0; / / event parameter while () {ionization +; / / trigger event if (NewLineRead! = null) NewLineRead (this, I) / /.} / / the following is the Client code private void CallMethod () {/ / declare the Class variable without WithEvents private DataImports _ da = null; / / specify the event handler _ da.NewLineRead + = new MyEventHandler (this.DA_EnterNewLine); / / call the Class method, and the event _ da.ImportData () will be triggered on the way. } / / event handler private void DA_EnterNewLine (object sender, long lineNumber) {/ /.} above is all the content of the article "how to design custom events using delegate types in C #". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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