Question

I have a form that contains an object “TextBox1” (TextBox1 control)

In the code section I’ve initialized a new TextBox object that is not on the form like this:

  Dim aa As New TextBox
  aa = TextBox1 'THE CONTROL ON THE FORM
  aa.Text = "hi how are you?"

The TextBox1 on the form is now changed it wrote “hi how are you?”

shouldn’t be the “aa” object and the “TextBox1” be separate one from another? means that changing one object wouldn’t affect the other?

Why this happens?
And how to prevent this?

Means Separating the objects one from another.

Writing the code at this form

Public Sub blah(ByVal aa As TextBox)
    aa.Text = "hi how are you?"
End Sub

And then calling the sub by

    blah(TextBox1)

Doesn’t solve the problem.

Answer 1

.Net objects are passed by reference.
aa and TextBox1 both refer to the same TextBox instance.

You can manually create a copy of an instance by copying over its properties to a different instance.