SQLDataReader 行数

Question

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";

Answer 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.

Answer 2

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

Answer 3

这将为您提供行数，但最终会离开数据读取器。

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

Answer 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);
     }
 }