Question

I have a series of DataRow objects, each with a bunch of different fields. What I want to do is create a new DataRow object with the total of certain decimal fields. Right now, my code looks something like this:

DataRow tally = myTable.NewRow();

foreach (DataRow row in myTable.Rows)
{
   if (row["SomeField"] != DBNull.Value)
      tally["SomeField"] = (tally["SomeField"] is DBNull ? 0 : (Decimal)tally["SomeField"]) + (Decimal)row["SomeField"];

   // ...     
}

I need to do the same with about 20 other fields, but I think the code is incredibly messy due to all the type-casting and null checking. Is there perhaps a way to refactor this code to be a bit more readable?

Note: I only want to tally up certain columns, otherwise I’d probably just loop through the columns in the DataRow rather than repeating the above code 20 times.

Answer 1

You could move your calculation code into a new method:

private void Tally(DataRow tally, DataRow row, int index)
{
    if (row[index] != DBNull.Value)
    {
        tally[index] = (tally[index] == DBNull.Value ? 0 : (decimal)tally[index]) + (decimal)row[index];
    }
}

and use an array of indexes for the columns you want to tally:

DataRow tally = myTable.NewRow();

int[] indexes = new int[] { 0, 2 };

foreach(DataRow row in myTable.Rows)
{
    foreach(int index in indexes)
    {
        Tally(tally, row, index);
    }
}