Question

So I want a pointer to a pointer.

I’ve got a class that is updated in one object. In another object I want a reference to the current version of the object in the original Class. Here is sort of a simplified version of what I have going on.

Public Class Foo
    'conaints information

End Class

Public Class myMainApp
    Dim myHelper As HelperClass
    Dim currentFoo As Foo

    Private Sub init()
        currentFoo = New Foo()
        myHelper = New HelperClass(currentFoo)
    End Sub

    Private Sub UpdatingUI()
        currentFoo = GetFooFromContext()
    End Sub

    Private Function GetFooFromContext() As Foo
        Return New Foo()
    End Function
End Class


Public Class HelperClass
    Private myFoo As Foo

    Public Sub New(ByVal aFoo As Foo)
        myFoo = aFoo
    End Sub
End Class

if thise was C++, currentFoo would be a Foo* and HelperClass’s myFoo would be a Foo** so that whenever we updated currentFoo’s refrence to a new object the HelperClass would also be accessing this new object.

Is there syntax to accomplish this in the .net world?

Answer 1

Reed’s answer is the typical idiomatic C# way to handle this, but if you really want it, you can always just introduce your own “reference wrapper” helper class:

public class Reference<T> where T : class
{
    public T Value { get; set; }
}

Then declare both currentFoo and myFoo as Reference<Foo>, and also make sure that currentFoo is readonly, so that no-one can assign a different Reference to it.