Solved

Extend vb.Net Class to have New Property

Posted on 2013-05-22
3
387 Views
Last Modified: 2013-05-22
How do you add an new property to an existing .Net Class.   What I want ot do exactlyis add a property to the dateTime class.

The goal would be like this.  
 
Dim intWeek as integer = DateTime.Now.WeekOfMonth

Open in new window


Here is the code I use to get the week of the month.

 Dim DayNo As Integer = 0
                Dim DateNo As Integer = 0
                Dim StartingDay As Integer = 0
                Dim PayPerEndDate As Date = DateTime.Now
                Dim week As Integer = 1
                StartingDay = PayPerEndDate.AddDays(-(PayPerEndDate.Day - 1)).DayOfWeek
                DayNo = PayPerEndDate.DayOfWeek
                DateNo = PayPerEndDate.Day
                week = Fix(DateNo / 7)
                If DateNo Mod 7 > 0 Then
                    week += 1
                End If
                If StartingDay > DayNo Then
                    week += 1
                End If

Open in new window

0
Comment
Question by:pamsauto
  • 2
3 Comments
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 39188391
How do you add an new property to an existing .Net Class.
You can't...at least not without subclassing it--if it's not sealed. It appears you want to add a member to the Now property, which is a DateTime struct. Structs cannot be inherited. You could add and extension method that would *appear* to be a member method, but in reality it's just a static (Shared in VB) method.
0
 
LVL 75

Accepted Solution

by:
käµfm³d   👽 earned 500 total points
ID: 39188425
An example of an extension method:

Definition
Public Module MyExtensions

    <System.Runtime.CompilerServices.Extension()>
    Public Function WeekOfMonth(source As DateTime) As Integer
        Dim DayNo As Integer = 0
        Dim DateNo As Integer = 0
        Dim StartingDay As Integer = 0
        Dim PayPerEndDate As Date = source
        Dim week As Integer = 1
        StartingDay = PayPerEndDate.AddDays(-(PayPerEndDate.Day - 1)).DayOfWeek
        DayNo = PayPerEndDate.DayOfWeek
        DateNo = PayPerEndDate.Day
        week = Fix(DateNo / 7)
        If DateNo Mod 7 > 0 Then
            week += 1
        End If
        If StartingDay > DayNo Then
            week += 1
        End If

        Return week
    End Function
End Module

Open in new window


Usage
Dim intWeek as integer = DateTime.Now.WeekOfMonth()

Open in new window

0
 

Author Closing Comment

by:pamsauto
ID: 39188435
Very nice!
0

Featured Post

The New “Normal” in Modern Enterprise Operations

DevOps for the modern enterprise offers many benefits — increased agility, productivity, and more, but digital transformation isn’t easy, especially if you’re not addressing the right issues. Register for the webinar to dive into the “new normal” for enterprise modern ops.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
JQuery JavaScripot loop though RadioButtonList 4 32
Can't disable touch pad on Windows 10 computer 16 45
Help with error in Query 2 31
Easy filter aspnet 2 24
In my previous two articles we discussed Binary Serialization (http://www.experts-exchange.com/A_4362.html) and XML Serialization (http://www.experts-exchange.com/A_4425.html). In this article we will try to know more about SOAP (Simple Object Acces…
This article shows how to deploy dynamic backgrounds to computers depending on the aspect ratio of display
This video shows how to use Hyena, from SystemTools Software, to bulk import 100 user accounts from an external text file. View in 1080p for best video quality.

792 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question