problem in sum payments method
please someone help me
I have method that return payments values sum for workers imprests
public static double PaymentsvalueSum(int id)
{
string strconn = myproject.Properties.Settings.Default.SalariesConnectionString;
OleDbConnection conn = new OleDbConnection(strconn);
if (conn.State == ConnectionState.Closed)
{
conn.Open();
}
OleDbCommand command = new OleDbCommand("select SUM(Payment_Value) from imprests_payments WHERE Imprest_ID=@id;", conn);
command.Parameters.Add(new OleDbParameter("@id", id));
double sumvalue = (double)command.ExecuteScalar();
try
{ }
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
conn.Close();
}
return sumvalue;
}
when button_click event I write
private void button1_Click(object sender, EventArgs e)
{
double val = ImprestsPaysMgr.PaymentsvalueSum(int.Parse(GridViewImprestsPays.CurrentRow.Cells["Imprest_ID"].Value.ToString()));
textBox1.Text = val.ToString();
}
this code is working perfectly when payments values in imprests_payments table is available but my problem is when no payments values is available in imprests_payments table
where the following error is rising
Object reference not set to an instance of an object.
I need the solution for this problem