Fill an array (or arrayList?)

[Guest Danno]

I am trying to add some numbers to an array and I am getting an error. Here is the code:

 

 

  
       Dim rate(17) As ArrayList
       Dim count As Short
       Dim startRate As Single = 6.0

       For count = 0 To 16
           rate(count).Add(startRate)
           startRate += 0.00125
           lstDisplay.Items.Add(rate(count))
       Next

 

And the error I get is:

 

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

 

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

 

What am I missing?

[divil]

You're missing knowledge of the difference between an array and an ArrayList. I can't really tell what you're trying to accomplish with this piece of code, but you probably want either of these:

 

Dim rate(17) As Double

or

Dim rate As ArrayList = New ArrayList() 'Then rate.Add(etc etc)

[Derek Stone]

An ArrayList is a type of collection, just in case you're wondering. You can't loop through it's elements that simply. You need to create an IEnumerable object if you want to enumerate through its elements.

[Guest Danno]

I am trying to display an interest rate starting at 6% through 8% in a ListBox in .125% increments. I wanted to put them into an array and then display them.

 

With "Dim rate(17) As Double" is rate an array filled with values that are doubles? I don't have to explicitly declare it as an array?

 

I will look into IEnumerable object (haven't used it yet)

[Derek Stone]

With "Dim rate(17) As Double" is rate an array filled with values that are doubles?

Yes

I don't have to explicitly declare it as an array?

No, you don't.