Converting a DataTable Column to an Array?

[James Shao]

Hi, I am having some trouble with creating a simple function that converts a column of a datatable to an array (containing all numbers). Upon running it, it says "Index was outside the bounds of the array"; however, I couldn't understand why my function would create this problem. :( Also since I do not usually program using VB.Net, I am not sure if my function has other errors (like syntax errors). Could you please help me check it out? I'd greatly appreciate it! :) Thanks in advance. Here's my VB function: Public Function DatatableToArray(ByVal dt As DataTable, ByVal intColomn As Integer) As Double() Dim intRows As Integer = dt.Rows.Count Dim arrValues() As Double = New Double(){} Dim i2 As Integer For i2 = 0 To intRows - 1 arrValues(i2) = dt.Rows(i2).Item(intColomn) Next Return arrValues End Function

[dan sh]

Check the value in intColumn variable.

50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong...!!

[Covean]

I'm not really confirm with the VB-Syntax but arrValues(i2) = dt.Rows(i2).Item(intColomn) looks like you try to access an double array that is not initialized (or doesn't have enough space). Look at you definition: Dim arrValues() As Double = New Double(){} <- maybe here you should say that this array should have dt.Rows.Count elements

Greetings Covean

[Kannan Ar]

Declare arrValues with a specific size. Like this

Dim arrValues() As Double = New Double(dt.Rows.Count - 1) {}

[Abhishek Sur]

First of all why dont you use List.... as your collection. It is always better to use ArrayList or Generic List as collection rather than going for Array. Next, I always prefer to use ForEach rather than For when I am looping through an Enumerable. If I was in your situation I would write this as :

Private Function DataTableToArray(ByVal x As DataTable, ByVal intCol As Integer) As List(Of Double)
    Dim lst As New List(Of Double)

    For Each dr As DataRow In x.Rows
        lst.Add(dr.Item(intCol))
    Next

    Return lst
End Function

Or if you still want to use Array you might use List(Of Double).ToArray as well. Cheers. :rose:

Abhishek Sur **Don't forget to click "Good Answer" if you like this Solution.

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[James Shao]

Thanks a lot guys. As soon as I'm home I'll give all of these options a try. :)

[carlecomm]

Hi, try the following code: Dim arrValues(0 To intRows - 1) As Double instead of Dim arrValues() As Double = New Double(){}

[James Shao]

Thank you guys, my problem is solved! :) Greatly appreciate it.