Array problem

[DR00ME]

Hello, how do I check if an array exists or there is reserved memory for it?

 

I need it in situation like this...

 

Private SC as Byte ' Selected Curve

If ArrayC(SC).DotArray(0) "exists" Then 'Here I want to check if there is reserved memory for e.g. first place of the array, if not then i reserve it and put mouse cordinates in it..

           ReDim Preserve ArrayC(SC).DotArray(0)
           ArrayC(SC).DotArray(0).X = e.X
           ArrayC(SC).DotArray(0).Y = e.Y

End if

[snarfblam]

To check if an array is created, compare it to Nothing. To see how many elements are declared for an array, compare to the Array.Length property.

Imports System.Windows.Forms

Dim MyArray As Byte()
   
Sub CreateMyArray()
   MessageBox.Show("Creating Array.")
   MyArray = New Byte() {1, 2, 3, 4}
End Sub

'Checking if an array is declared.
Sub CheckMyArray()
   If MyArray Is Nothing Then
       MessageBox.Show("Array Not Created.")
   Else
       MessageBox.Show("Array Created.")
   End If
End Sub

'Checking that a specified index exists  
Sub CheckElements(Index As Integer)
   If MyArray Is Nothing OrElse MyArray.Length <= Index Then
       MessageBox.Show("Index " & Index.ToString() & " does not exist.")
   Else
       MessageBox.Show("Index " & Index.ToString() & " does exist.")
End Sub
   
'Demonstration
Public Sub Demo
   CheckArray()
   CreateArray()
   CheckArray()
   CheckElements(3)
   CheckElements(4)
End Sub

[DR00ME]

yes I was looking for the "is nothing" thingy.... heh, my bad... forgot parentheses after the array...

 

 

thank you...

[Diesel]

Why not use more high level data structures in a more object oriented fashion?

 

Translation: That's some ugly code!