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byref in vb.net

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Join Date: Apr 2008

Posts: 26

Reputation: dan_e6 is an unknown quantity at this point

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dan_e6

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byref in vb.net

Jun 11th, 2008

hey guys.
here is a scenario:

i have a form named frm1 and a variable in it

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
 private x as integer = 0
 private x as integer = 0

and another form called frm2 that needs to be able to make a local copy of "x" from frm1 and any changes made to "x" on frm2 needs to be changed on frm1.

so in frm2 i do

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
 
private number as integer 
 
Public Sub New(ByRef x as integer)
 
number = x
 
end sub
private number as integer 

Public Sub New(ByRef x as integer)

number = x

end sub

and from frm1 i create frm2 as follows:

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 VB.NET Syntax (Toggle Plain Text) 
 
public sub createfrm()
 
dim frm as new frm2(x)
frm.showdialogue()
 
end sub
public sub createfrm()

dim frm as new frm2(x)
frm.showdialogue()

end sub

and now any changes made to 'number' inside frm2 should change 'x' in frm1 shouldnt it? this does work if you're using a textbox object since the project im working in does exactly that. but when i try and do it for a variable like single/string/integer it doesnt work. it changes the local variable on frm2 but not the variable on frm1.

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Join Date: Feb 2008

Posts: 513

Reputation: selvaganapathy is an unknown quantity at this point

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selvaganapathy selvaganapathy is offline

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Re: byref in vb.net

Jun 12th, 2008

Hi,
I think Single, Integer, Double Char all are ValueType, So It is not working. Also you can override the ShowDialog() and pass your value

For Example In Form2

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
    Public Shadows Sub ShowDialog(ByRef x As Integer)
        MyBase.ShowDialog()
        x = 566
    End Sub
    Public Shadows Sub ShowDialog(ByRef x As Integer)
        MyBase.ShowDialog()
        x = 566
    End Sub

To Show Form2 In Form1
Declare
Private Number as Integer

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
   Dim NewForm As New Form2
   MessageBox.Show(Number)
   NewForm.ShowDialog(Number)
   MessageBox.Show(Number)
   Dim NewForm As New Form2
   MessageBox.Show(Number)
   NewForm.ShowDialog(Number)
   MessageBox.Show(Number)

I am using MessageBox to Show before and After calling the ShowDialog