SQLDataReader Row Count

问题

I am trying to get the number of rows that were returned by iterating the reader. But I always get 1 when I run this code? Did I screw up something in this?

int count = 0;
if (reader.HasRows)
{
    while (reader.Read())
    {
        count++;
        rep.DataSource = reader;
        rep.DataBind();
    }
}
resultsnolabel.Text += " " + String.Format("{0}", count) + " Results";

回答1:

SQLDataReaders are forward-only. You're essentially doing this:

count++;  // initially 1
.DataBind(); //consuming all the records

//next iteration on
.Read()
//we've now come to end of resultset, thanks to the DataBind()
//count is still 1 

You could do this instead:

if (reader.HasRows)
{
    rep.DataSource = reader;
    rep.DataBind();
}
int count = rep.Items.Count; //somehow count the num rows/items `rep` has.

回答2:

 DataTable dt = new DataTable();
 dt.Load(reader);
 int numRows= dt.Rows.Count;

回答3:

This will get you the row count, but will leave the data reader at the end.

dataReader.Cast<object>().Count();

回答4:

Maybe you can try this: though please note - This pulls the column count, not the row count

 using (SqlDataReader reader = command.ExecuteReader())
 {
     while (reader.Read())
     {
         int count = reader.VisibleFieldCount;
         Console.WriteLine(count);
     }
 }

来源：https://stackoverflow.com/questions/5502863/sqldatareader-row-count