Thread: Exception "Object reference not set to an instance" iterating DataGrid

Hi!

i tried to iterate the DataGrid Control with below code:

Code:

String strSelDvdCat = cbDvdCat.SelectedItem.ToString();
            String strCat;
            int irowindex = 0;


            foreach (DataGridViewRow row in dgvViewDvds.Rows)
            {
                try
                {
                    DataGridViewCell cell = row.Cells[2];//Cat colum (2)

                    strCat = cell.Value.ToString();

                    //if (!(strSelDvdCat.ToLower().Contains(strCat.ToLower())))
                    {
                        dgvViewDvds.Rows.RemoveAt(irowindex);
                        MessageBox.Show(irowindex.ToString());

                    }
                    irowindex++;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message.ToString());
                }
            }

The foreach() loops only about 4 times when i have 10 rows in the DataGrid. And then it gives the exception "Object reference not set to an instance", and quits the loop. Why does the loop stop prematurely?

Thanks for any help.

Code:

foreach (DataGridViewRow row in dgvViewDvds.Rows)
            {
...
                   dgvViewDvds.Rows.RemoveAt(irowindex);
...

You can't modify a foreach enumerator inside the loop. It's not allowed. You'll have to do something like creating a list of rows to remove, and then remove all of the rows in that list after the foreach loop.

Thanks. Yes my bad. i just used the hide() function to hide the rows instead of trying delete 'em.