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Almost every one of us knows about passing objects by Value and by Reference, it is perhaps one of the lesser cared about aspects in programming. But if left unnoticed, it can cause unexpected results in our applications.
This code sample demonstrates how we can pass a value by Reference and by Value in .NET viz. VB.NET and C#.
Save this file as PassVal.vb
Imports System
Imports Microsoft.visualbasic
Class TestRef
Sub Change(ByRef
i As String)
i = "Changed"
End Sub
Sub DontChange(ByVal i As String)
i = "Some Text"
End Sub
End Class
Class PassValue
Shared Sub main()
Dim objT As New
TestRef()
Dim sChange As String = "DotNetExtreme"
Dim sDontChange As
String = "DotNetExtreme"
'Value of sChange will change
MsgBox("Before = " & sChange)
objT.Change(sChange)
MsgBox("After = " & sChange)
'Value of sDontChange will not change
MsgBox("Before = " & sDontChange)
objT.DontChange(sDontChange)
MsgBox("After = " & sDontChange)
End Sub
End Class
Compile the file from the command prompt as VBC Passval.vb.
Source: DotNetExtreme.com
