Question

I have a variable whose scope needs to be global, because it needs to be called in a function as well as in a button press. So I declared the variable in a Module so it would be global.

The problem is that the value of this variable needs to be equal to the value of the text property of a textbox in the form.

Here you can download the VB.net demonstration of my problem: http://db.tt/DDxQJDXl

Below is an explanation of what happens

You enter a string into the textbox, in this case I entered “Hello”. Then you click the button and it displays what you wrote.

You click OK in that message box and change the value in the textbox. In this case I changed it to “Goodbye”. Then I hit the button again, but the variable did not change values and the messagebox displays “Hello” again.

Here is the entire source code:

Module Module1
     Public strDataValue = frmTest.txtDataValue.Text
End Module
Public Class frmTest
    Private Sub btnTest_Click(sender As System.Object, e As System.EventArgs) Handles btnTest.Click
        MsgBox(strDataValue)
    End Sub
End Class

Note: This is just a demonstration of a problem I’m having in a much larger program so the variable does have to be global.

Answer 1

You need to set the value of the field to the new value in the TextBox:

Private Sub btnTest_Click(sender As System.Object, e As System.EventArgs) Handles btnTest.Click
    strDataValue = txtDataValue.Text
    MsgBox(strDataValue)
End Sub

The field will not change values by itself.