Fix: Object reference not set to instance of object

Prabhat 7154it

The exception is thrown at line if (bool.Parse(row.Cells[0].Value.ToString())).

Exception details:

System.NullReferenceException: 'Object reference not set to an instance of an object.'

System.Windows.Forms.DataGridViewCell.Value.get returned null.

private void btnDeleteCategory_Click(object sender, EventArgs e)

{

foreach (DataGridViewRow row in CategoryGV.Rows)
{
if (bool.Parse(row.Cells[0].Value.ToString()))
{
string cs = ConfigurationManager.ConnectionStrings["aladin"].ConnectionString;
SqlConnection con = new SqlConnection(cs);
SqlCommand cmd = new SqlCommand("DELETE FROM lwpos_categories WHERE id= '" + Convert.ToInt32(row.Cells[1].Value) + "' ", con);
con.Open();
cmd.ExecuteNonQuery();
con.Close();
}
}

MessageBox.Show("Deleted Successfully", "Successfull operation", MessageBoxButtons.OK, MessageBoxIcon.Information);

}

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Rajanikant Hawaldar6y ago
Problem is your not doing null check before access Value from row.Cell[0] thats the reason your getting error i correcred the code please use it.
private void btnDeleteCategory_Click(object sender, EventArgs e)
   {
       foreach (DataGridViewRow row in CategoryGV.Rows)
       {
           if (!string.IsNullOrEmpty(row.Cells[0]) && !string.IsNullOrEmpty(row.Cells[0].Value))
           {
               if (bool.Parse(row.Cells[0].Value.ToString()))
               {
                   string cs = ConfigurationManager.ConnectionStrings["aladin"].ConnectionString;
                   SqlConnection con = new SqlConnection(cs);
                   SqlCommand cmd = new SqlCommand("DELETE FROM lwpos_categories WHERE id= '" + Convert.ToInt32(row.Cells[1].Value) + "' ", con);
                   con.Open();
                   cmd.ExecuteNonQuery();
                   con.Close();
               }
           }
       }
       MessageBox.Show("Deleted Successfully", "Successfull operation", MessageBoxButtons.OK, MessageBoxIcon.Information);
   }
0
Ronika Jency6y ago
Hi,

you don't have value in this line row.Cells[0].Value.ToString(). that is the reason you are getting exception. handle the case value is there and not.

do you want convert string to boolean ?

what is the value contain row.Cells[0].Value.
+1