Question

All i want to do is access my property from a parent Form in vb.net Forms.
but it won’t let me do

 Dim formParent1 As formParent

 Private Sub search()
 formParent1.propertyName = 1
 End Sub

but it gives an error at formParent1.propertyname = 1. Saying “Object reference not set to an instance of an object”.

but i may not use

Dim formParent1 as formParent = new formParent()

how can I access this propery, I am new at VB.net
best regards

Answer 1

If I understand you correctly, that code is inside a child form of formParent. To use a reference to the current formParent you need to pass inside the child form a reference to this current formParent.

So in the formParent, when you start the execution of the child form, write this:

Dim f as formChild = new formChild(Me)
f.ShowDialog() 

in the form child constructor save the passed reference to the global variable formParent1

Dim formParent1 as formParent ' this is the global level reference to the parentForm'

Public Sub formChild(ByVal f as formParent)
       formParent1 = f
End Sub

now you can use the reference formParent1 inside the child form without initialize another formParent
For example, assuming that the formParent1 contains a public property named SearchResult, when you complete your search you call:

Private Sub searchBtn_Click(sender As Object, e As System.EventArgs) Handles SearchButton.Click
     Dim searchResult as String

     ' Here write the code that executes the search and set the value in searchResult variable

     ' Pass the searchResult variable to the parent form via the global reference.
     formParent1.SearchResult = searchResult
End Sub