SQLDataReader行计数

Question

我试图通过迭代读取器获得返回的行数.但是当我运行这段代码时,我总是得到1？我搞砸了吗？

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是仅向前的.你基本上是这样做的:

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 

你可以这样做:

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,但会将数据读取器留在最后.

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