What is ByVal and ByRef in vb.net.Please explain with examples.

Hi Kundan,


ByVal:-  means  passing a copy of a variable to your Subroutine. You can make changes to the copy and the original will not be altered.

ByRef:-  means that you are not handing over a copy of the original variable but pointing to the original variable.Here original value will be changed.



Ex:-


Dim x, y As Integer
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        x = 20
        y = 30
        MsgBox("original value=" & x & " , " & y)
        change1(x)
        change2(y)
        MsgBox("changed value=" & x & " , " & y)
    End Sub
    Sub change1(ByVal x As Integer)
        x = x + 10
    End Sub
    Sub change2(ByRef y As Integer)
        y = y + 10
    End Sub



Result

original value= 20,30

changed value= 20,40



Thanks