Datagridview cell validation

1.As can be seen in the attached screenshot, the company name attribute (first row) has not been specified, the user should not be able to leave a mandatory row(AttIsMandatory column) before this is done, please provide an example of how to use the error text based on 2 conditions:

a.      Where the cell is empty
b.      The attribute is mandatory.                   
My code only handles one condition
private void dataGridView1_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)
        {
               
            //Check that all mandatory values are supplied
            if (e.ColumnIndex == 5) //if (dataGridView1.Rows[rowIndex].Cells["Column2"].Value.ToString()!= "")
            {
                if (dataGridView1.Columns[e.ColumnIndex].Name == "c_attIsMandatory")
                {
                    if (String.IsNullOrEmpty(e.FormattedValue.ToString()))
                    {
                        dataGridView1.Rows[e.RowIndex].ErrorText = "Mandatory information must be supplied";
                        e.Cancel = true;
                    }
                }
            }

            //if ((dataGridView1.Columns[e.ColumnIndex].Name == "c_attIsMandatory") && (dataGridView1.Columns[e.ColumnIndex].Name == "c_AttVal"))
        }


dgv-small.jpg