Question

int a ;

SqlCommand cmd = new SqlCommand (" Select * From items order by ItemID ", conn );

SqlDataReader reader = cmd.ExecuteReader();

while(reader.Read())
        {
            a = reader.GetInt32(0);

            if (reader.HasRows == false)
            {
                dataGridView1.Visible = false;
            }

            else
            {
                dataGridView1.Visible = true;

                DataTable dt = null;

                dt = new DataTable();

                dt.Load(reader);

                dataGridView1.DataSource = dt;

                if (reader.IsClosed == true)
                {
                        break;
                }   
            }

I want to ask that is the reader closed automatically, because here am not using reader.Close() and still it is closed? also , in my items table i have the first record as

ItemId | ItemName

 1       Bag
 2       Laptop
 8       Weighing Machine 

But, when this data is displayed in the datagridview then the row 1 , that is, the itemname “BAG” is not displayed. why so?

Answer 1

By calling Read(), you have already “claimed” the first row (hence why Bag isn’t showing – because you aren’t doing anything with it); and yet dt.Load is also going to do a while(reader.Read()). I expect you want (note I’m not calling Read here, and have no while loop):

if(reader.HasRows)
{
   // load via dt.Load() and show
}
else
{
     // hide
}

The reason it is exiting is that once you’ve called Load you’ve already read all the data, so there is nothing else to read. I honestly don’t know whether getting to the end of the TDS stream implicitly closes the reader, but you should be using:

using(var cmd = new SqlCommand (" Select * From items order by ItemID ", conn))
using(var reader = cmd.ExecuteReader()) 
{
     // everything else in here
}