Question

Please help me to understand how to use class to share variables.
I have 3 forms and one class to store some variables. Inside form1 I am calling myclass and setting up variables. Now I show form2 and inside form2 I call form3

Is it possible to get variable from a class , which I have sent from first form ?
Myclass code looks like this :

    Private _var As String
Public Sub setvar(ByVal var As String)
    _var = pvar
End Sub

Public Function getvar() As String
    Return _var
End Function

from form1 :

       Public class1 As myclass
      class1 = New myclass
       class1.setvar("test")

Now I want to call class1.getvar and I want it return the value which I have entered in a first form. is it possible ? if yes please help me how ?

Thanks

Answer 1

Because you have used the ‘Public’ access modifier on you ‘class1’ variable definition you should be able to access it as a field on Form1 from anywhere that has access to that instance of Form1.

Dim myString as String = form1.class1.getvar()

It would probably be neater not to do it this way though.

OPTION1
If it were me I would prefer to create the instance of MyClass in the first form and then pass that instance to the other forms (possibly through the constructor).

Public Class Form1

   Private _instance As MyType


   Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
      _instance = New MyType

      Dim newForm As New Form2(_instance)
   End Sub

End Class
Modify the New method of Form2 and Form3 to accept a parameter of type MyClass:

Public Class Form2

   Private _instance As MyType

   Sub New(instance As MyType)
      _instance = instance
   End Sub

End Class

Then you are passing the variable in when you create the new form and storing it in a private member that you can access anywhere in the code of the second form.

OPTION2
Alternatively, you could put the definition of class1 into a module and then you could access it from wherever you want in the project.