Delegate, DOT NET Programming

Assignment Help:

What is a delegate?

The Delegate is the class that can hold a reference to a method or a function. The Delegate class has a signature and it can only reference to those methods whose signature is compliant with the class. The Delegates are type-safe functions pointers or callbacks.

The sample code is shown below which shows an example of how to implement delegates.

Public Class FrmDelegates

Inherits System.Windows.Forms.Form

Public Delegate Sub DelegateAddString()

Private Sub FrmDelegates_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

End Sub

Private Sub AddString()

lstDelegates.Items.Add("Running AddString() method") End Sub

Private Sub cmdDelegates_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdDelegates. Click

Dim objDelegateAddString As DelegateAddString objDelegateAddString = AddressOf AddString objDelegateAddString.Invoke()

End Sub

End Class

In the above code there is a method called "AddString()" that adds a string to a listbox. You can also view a delegate declared as:-

Public Delegate Sub DelegateAddString()

This delegate signature is compatible with all the "AddString" method. When I say compatibility that means that there return types and passing parameter types are similar. After in command click of the button object of the Delegate is created and the method pointer is received from "AddressOf" keyword. Then by using "Invoke" method the method is invoked.

 

668_delegate.png

Figure:-Delegate in Action


Related Discussions:- Delegate

Targin protocol and stock market protocol, Project Description: We need ...

Project Description: We need to construct services in C# or VB.NET that can manipulate with a Targin TIP Protocol Server (protocol for financial information exchange), receive d

Difference between server.transfer and response.redirect, What is the diffe...

What is the difference between Server.Transfer and response.Redirect? The difference  between the Server.Transfer and the response.Redirect them are as follows:- 1)Response.

How do we provide parameters to the stored procedures?, The ADO.NET gives t...

The ADO.NET gives the SqlCommand object which gives the functionality of executing the stored procedures. CREATE PROCEDURE SelectByEmployee @FirstName nvarchar(200) AS Se

Explain the concept of constructor, Explain the concept of constructor? ...

Explain the concept of constructor? Constructor is a special method of a class, which is called automatically when the instance of a class is formed. It is created with the sam

Relation between classes and objects, What is the relation between Classes ...

What is the relation between Classes and Objects? The class & object look very much same but are not same. The Class is a definition, while object is a instance of the class cr

Difference between datagrid, What's difference between Datagrid, Datalist a...

What's difference between Datagrid, Datalist and repeater? The Datalist ,Datagrid, and Repeater are all ASP.NET data Web controls. They have many things in common such as Da

Explain class, What is a class? A class explains all the attributes of ...

What is a class? A class explains all the attributes of objects, as well as the methods that execute the behavior of member objects. It is a comprehensive data type, which show

What is the scope of public and private class, What is the Scope of public/...

What is the Scope of public/private/friend/protected/protected friend? Scope of public/private/friend/protected/protected friend Visual Basic/Visual C# Public/public all

I need export data using json, I need Export Data using JSON Project Des...

I need Export Data using JSON Project Description: We could like to share our data with other websites via JSON. We are presently using Entity Framework with MySQL. We req

Need experienced dot net and php programmers, Need Experienced dot Net and ...

Need Experienced dot Net and PHP Programmers Project Description: Need Experienced dot Net., JSP, PHP, Java Programmers Skilled professional and command in Programming eit

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd