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Datagridview  **insert rows

Posted on 2007-12-03
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Last Modified: 2013-11-26
I am trying to populate a datagridview with rows obtained from a file.  
The file has rows broken up by a semi-colon.  The information i need populated in the cells of the datagridview are the values after the semicolon.

What my program does is read the lines of the code.  Then i am trying to remove from the input string all the values to the left of the semi-colon and then inputting that value into the datagridview row.  For some reason VB is telling me to create an instance of a "new" object.  I am not seeing why however.
DataGridView1.Rows.Add()    'ROW ADDED

            varcount = DataGridView1.Rows.Count  'MAX ROWS OF DATAGRIDVIEW

            For xvar As Integer = 0 To 5   'LOOP INPUT FILE

                Dim varstr  

                Dim line  'STRING CONTAINING INPUT

                Dim pos As Integer 'POSITION OF SEMI-COLON
 

                line = sr.ReadLine   'READS LINE

                pos = InStr(line, "; ")  'GETS POSITION OF SEMI-COLON

                varstr = line.Remove(0, pos)  '>>>>>ERROR HERE<<<<<

                DataGridView1.Rows(varcount - 1).Cells(xvar).Value = varstr  'INPUT COLUMN CELLS

            Next xvar

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Question by:alexander001
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aperion earned 250 total points
ID: 20401414
I'd try a couple of different things.  If you have to keep the code the way you have it then try removing the space after the semi-colon in this line:

pos = InStr(line, "; ")  'GETS POSITION OF SEMI-COLON

Declaring your varstr variable as an array allows you to use the split function.   If neither one of these will work for you then I'd try stepping through the code using breakpoints and see what the variables values are and which one if any is throwing the error.

DataGridView1.Rows.Add()    'ROW ADDED

        varcount = DataGridView1.Rows.Count  'MAX ROWS OF DATAGRIDVIEW

        For xvar As Integer = 0 To 5   'LOOP INPUT FILE

            Dim varstr() As String

            Dim line As String = ""  'STRING CONTAINING INPUT

            line = sr.ReadLine   'READS LINE

            varstr = line.Split(";")

            DataGridView1.Rows(varcount - 1).Cells(xvar).Value = varstr  'INPUT COLUMN CELLS

        Next xvar

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by:alexander001
ID: 20403145
Still getting an error.  It's a weird one.  When i run it there's an immediate window that states " A first chance exception of type 'System.NullReferenceException' occured"

Plus when i run through the code i get the error "User the "new" keyword to create an object instance"

These messages come in on my original code at line:
           varstr = line.Remove(0, pos)
and when i use the suggested code for the string array at line:
           varstr = line.Split(";")

Any ideas?
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Expert Comment

by:aperion
ID: 20405958
Set a breakpoint at that line and see which variales are nothing.
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