array length unknown? adding more to an array? [resolved]

[joeframbach]

i dont know how to do things with arrays, please help me

im using this code:

Dim sr As StreamReader = File.OpenText("users.txt")
Dim users()() As String

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim i As Integer = 0
Dim x As Integer = 0
Do While sr.Read
users(x)(0) = sr.ReadLine
users(x)(1) = sr.ReadLine
x += 1
Loop
sr.Close()
End Sub
Dim sr As StreamReader = File.OpenText("users.txt")
Dim users()() As String

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim i As Integer = 0
Dim x As Integer = 0
Do While sr.Read
users(x)(0) = sr.ReadLine
users(x)(1) = sr.ReadLine
x += 1
Loop
sr.Close()
End Sub

im getting this error:

An unhandled exception of type 'System.NullReferenceException' occurred in first.exe

Additional information: Object reference not set to an instance of an object.

can someone plz help me?

[Mr.No]

You have to dimension the array before use. Since it is a 2 dimensional array, you can only use Redim on the last index. But, you cannot use Redim on a module level variable.
Why don't you use the ArrayList datatype?

[joeframbach]

can you tell me more about arraylists? i cant seem to find it in the help index

[Athley]

Search for "ArrayList Class" in the help and choose the topic with the same name.

[joeframbach]

i must be missing something here...

it seems to me that arraylists are not for .net? i get an error: arrays cannot be declared with 'new'.

[Mr.No]

You have to reference the System.Collections class and then
try this:

dim myList as new Arraylist

As for help system, do a search on "ArrayList". You should get something even if you have just the .NET SDK and don't have VS.NET

[joeframbach]

should i put Imports System.Collections at the top, or can i do Dim myList As New System.Collections.ArrayList()