Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

Referencing a function in another class using vs 2003

Posted on 2006-06-14
1
Medium Priority
?
201 Views
Last Modified: 2010-05-18
I am currently converting to visual studio 2003 from vs 2005, however I have encountered a problem with the Shared functions.

In 2005 I can reference a Friend sub from another form, In 2003 I get an error saying 'Reference to a non-shared member requires an object reference.
 
If I create an instance of the form in the second form the error message goes away but this creates a new reference of the form and does not display the correct info. How can I reference a function in another class using vs 2003?
Any ideas? thank you.
0
Comment
Question by:Kmeli
1 Comment
 
LVL 86

Accepted Solution

by:
Mike Tomlinson earned 2000 total points
ID: 16906127
In VS2005, the concept of a "default instance" was brought back into the mix.  This works exactly the same way as it did in VB6...you can use the Forms name to reference the default instance and it can be accessed from anywhere.

VS2002/VS2003 had no such feature.

In those versions you must have a reference to the actual instance of the form you want to deal with.

If you just created the form then you already have an instance.  As in...

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim f1 As New Form1
        f1.Show()
        f1.TextBox1.Text = "something"
    End Sub

But if you are attempting to go the other way, as in updating the form that created "f1" in the previous example, from "f1" itself then you need to pass in a reference to that form.  One way to do this is to use the Owner() property:

    Public Class Form1
        Inherits System.Windows.Forms.Form

        Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            Dim f2 As New Form2
            f2.Owner = Me
            f2.Show()
        End Sub

    End Class

    Public Class Form2
        Inherits System.Windows.Forms.Form

        Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            Dim f1 As Form1 = CType(Me.Owner, Form1)
            f1.TextBox1.Text = "Form2 calling..."
        End Sub

    End Class

If you don't want to use Owner() then you can pass in a Reference like this:

    Public Class Form1
        Inherits System.Windows.Forms.Form

        Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            Dim f2 As New Form2
            f2.f1 = Me
            f2.Show()
        End Sub

    End Class

    Public Class Form2
        Inherits System.Windows.Forms.Form

        Public f1 As Form1

        Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
            If Not (f1 Is Nothing) Then
                f1.TextBox1.Text = "Form2 calling..."
            End If
        End Sub

    End Class

Another approach is to use the Singleton pattern.  This is useful if you will only have ONE instance of your form open at any time.  See my discussion and example here:
http://www.experts-exchange.com/Programming/Programming_Languages/Dot_Net/VB_DOT_NET/Q_21845440.html




0

Featured Post

Get expert help—faster!

Need expert help—fast? Use the Help Bell for personalized assistance getting answers to your important questions.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

There are many ways to remove duplicate entries in an SQL or Access database. Most make you temporarily insert an ID field, make a temp table and copy data back and forth, and/or are slow. Here is an easy way in VB6 using ADO to remove duplicate row…
When designing a form there are several BorderStyles to choose from, all of which can be classified as either 'Fixed' or 'Sizable' and I'd guess that 'Fixed Single' or one of the other fixed types is the most popular choice. I assume it's the most p…
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…
Suggested Courses
Course of the Month13 days, 3 hours left to enroll

579 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question