NullReferenceException

Code:

                    int countRows = dataGridView1.Rows.Count;

                    for (int i = 0; i < countRows + 1; i++)
                    {
                        if (int.Parse(dataGridView1.Rows[i].Cells[11].Value.ToString()) == 0)
                        {
                            dataGridView1.Rows[i].DefaultCellStyle.BackColor = Color.Red;
                        }
                    }

This code will be used to determine wheter a cell value (from a datagridview) is 0, if so it's background color will be red.

But i get a NullReferenceException at the red marked line.

So i have two questions:

1. How can i fix this?
2. Is it possible to get data from a cell by using it's columnname? Not like dataGridView1.Rows[i].Cells[11].Value.ToString() since the database column places can be changed.

Thanks in advance.

You're trying to access a row that doesn't exist. Remove the "+1" in the loop, then read up on which indices are valid in an array.

I removed the +1 and i went through the loop with a messagebox to check if i would get the values i want and i did.

So i don't know how to check what's wrong.

Fixed it, the +1 had to be -1

Originally Posted by Chronik

Fixed it, the +1 had to be -1

Then you're not including the last row...
May I suggest using enumerators to traverse the rows instead? Then you don't need to fiddle with indices.

Code:

foreach(System.Web.UI:WebControls.GridViewRow Row in dataGridView1.Rows)
{
   if (int.Parse(Row.Cells[11].Value.ToString()) == 0)
   {
      Row.DefaultCellStyle.BackColor = Color.Red;
   }
}