Is it possible to Dim a variable in VB.net using values from an array? - vb.net

Question

I need to create several text files in vb.net based on values entered in a spreadsheet. Each text file will be named 'valuename.txt'.
I populate an array with the value names as they are entered:
issues(j) = Grid1.Cells(1, j).Value
Now I need to open text files with their names. I would like to do something along the lines of:
Dim Filename As String = "C:\" & Grid1.Cells(1, j).Value & ".txt"
Dim issues(j) As New System.IO.StreamWriter(Filename)
When I enter this in Visual Studio, it says it does not like:
issues(j)
Do I have any other options?

Answer 1

It seems like the code you have posted is inside a for loop with j being the counting variable.
You are already building a filename from the cell values, so just declare the streamwriter as a new variable and use it:
For j = 0 To Grid1.Rows.Count - 1 'Assumed by me
'Create the filename for the current row
Dim Filename As String = "C:\" & Grid1.Cells(1, j).Value & ".txt"
'The Using block makes sure that the ressources used by the streamwriter are disposed again.
'It is equivalent as Dim sw As New IO.Streamwriter, but Using should be preferred
Using sw As New IO.StreamWriter(Filename)
'Use the streamwriter to write the data
End Using
'If you additionally want to store the values in an array for whatever reason
issues(j) = Grid1.Cells(1, j).Value
Next
Your Dim issues(j) statement does not make any sense.
To append data to an existing file, use the overload of the StreamWriter constructor:
Using sw As New IO.StreamWriter(Filename, True)
The second parameter defines if data should be added to the file.

Answer 2

You can use Using to declare a new StreamWriter:
Dim Filename As String = "C:\" & Grid1.Cells(1, j).Value & ".txt"
Using fsw As New System.IO.StreamWriter(Filename)
'Do Something
End Using
But if you insist to use a list of StreamWriter (I don't know why) then you can do something like this:
Dim fsw As New List(Of System.IO.StreamWriter)
fsw(j) = New System.IO.StreamWriter(Filename)
'Do Something
fsw(j).Close
fsw(j).Dispose