SQLDataReader行计数

Question

我试图通过迭代读取器来获取返回的行数。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，但会将数据阅读器留在最后。

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

Answer 4

也许你可以试试这个：虽然请注意 - 这会拉动列数，而不是行数

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