Index out of range exception in asp.net

Question

while trying to connect to the database i have written the following code in my page load method :

    SqlConnection con = new SqlConnection(constring);
    SqlCommand cmd = new SqlCommand();
    cmd.CommandType = CommandType.Text;
    cmd.Connection = con;
    con.Open();
    cmd.CommandText = "select pid from pid";
    SqlDataAdapter da = new SqlDataAdapter();
    DataSet ds = new DataSet();
    DataTable dt = new DataTable();
    da.SelectCommand = cmd;
    da.Fill(dt);
    a = Convert.ToInt32(dt.Rows[0][0].ToString()) + 1;
    con.Close();
    return a;

and im getting an error in the code line " a = Convert.ToInt32(dt.Rows[0][0].ToString()) + 1; " as: index out of range exception there is no row at position 0 how to proceed?

Answer 1

Presumably, your query is returning no rows. Handle accordingly (if it's possible that the query returns no rows, add an if statement). Otherwise, perhaps something is amiss with your query (selecting a column from an object of the same name doesn't seem right).

int retVal = default( int );

if( dt.Rows.Count == 1 )
{
    retVal = (int)dt.Rows[0][columnName];
}

return retVal;