Controls, Hashtables & NullReferenceException

[mike55]

Hi

 

I am using the following code:

 

  Private Sub ReloadSelectionCriteria(ByVal userSelection As Hashtable)
       For Each entry As DictionaryEntry In userSelection
           CType(Controls(entry.Key), ComboBox).SelectedItem = entry.Value
       Next
   End Sub

 

to loop through all the keys in a hash table. All the keys are the names of a valid combobox displayed on screen. What I am trying to do is to reflect the values chosen on the comboboxes on the parent screen through to the child screen. However, with the above code I am getting a NullReferenceException.

 

Any suggestions? I believe that the problem is that my code cannot find the control on the windows form.

 

Mike55.

[mike55]

Fixed my initial problem:

  Private Sub ReloadSelectionCriteria(ByVal userSelection As Hashtable, ByVal parent As Object)
       Dim myC() As Control

       For Each entry As DictionaryEntry In userSelection
           myC = Controls.Find(entry.Key.ToString, True)

           CType(myC(0), ComboBox).SelectedIndex = entry.Value
       Next
   End Sub

 

I now have an additional issue, the form that I am using is an instance of the parent form and both of them remain open on screen. When I cycle through the hashtable, the above code is simply looking at the parent form. How can I re-target it at the child form?

 

Mike55.

[mike55]

Solution:

Private Sub ReloadSelectionCriteria(ByVal userSelection As Hashtable, ByVal parent As Object)
       Dim myC() As Control

       For Each entry As DictionaryEntry In userSelection
           myC = parent.Controls.Find(entry.Key.ToString, True)

           CType(myC(0), ComboBox).SelectedIndex = entry.Value
       Next
   End Sub