Question

I am developing a program for a chain of restaurants, they should normally be able to calculate their guestcount and sales through a vb.net application with a connection to dbf files.
My dataset gets filled in correctly as is my datatable (checked by filling in datarowview = right data)
But then I get a problem, in all my functions using my datatable, the datatable skips the final value, in this case it is all values from a month so it either skips 31 or day 30.
Tried while, Tried for each, debugged alot (how i found it was the last value). But now I have no idea why the last value isn’t used by the function

    Public Function Getgctakeout(ByVal i_table As DataTable)
       table = i_table
       i = 0
       gctakeout = 0

    For Each row As DataRow In i_table.Rows

        gctakeout = gctakeout + Convert.ToDouble(row(4))

    Next row
        'MessageBox.Show(gctakeout)
    Return gctakeout
    End Function

This function does not use the value of the last row to calculate gctakeout

what in the name of the lord is wrong 🙂

Answer 1

Assuming that your DataTable is really filled correctly, you have two other options to get the sum.

1. Use the old DataTable.Compute method which works also with .NET < 2.0
2. Use Linq-To-DatSet and it’s Enumerable.Sum

1)

Dim Sum = CType(table.Compute("Sum(ColumnName)", Nothing), Double)

2)

Dim Sum = table.AsEnumerable().
                Sum(Function(row)row.Field(Of Double)("ColumnName"))