SQLDataReader 行计数

发布于 2024-10-28 21:20:29 字数 301 浏览 6 评论 0原文

我试图获取通过迭代读取器返回的行数。但是当我运行这段代码时我总是得到1？我是不是搞砸了什么？

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

原文

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";

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幽梦紫曦～ 2024-11-04 21:20:29

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

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

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小嗷兮 2024-11-04 21:20:29

SQLDataReaders 是只进的。你本质上是在这样做：

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.

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.

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我为君王 2024-11-04 21:20:29

这将为您提供行数，但会将数据读取器留在最后。

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

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

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

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玩世 2024-11-04 21:20:29

也许你可以尝试这个：不过请注意 - 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);
     }
 }

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);
     }
 }

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