SqlDataReader 返回 x 行,但 SQL 查询返回 y 行
本文关键字:返回 查询 SQL SqlDataReader | 更新日期: 2023-09-27 18:30:59
第一次发帖,因为我有点卡在这里。
我使用此代码从 SQL Server 数据库返回一些行:
public static SqlDataReader SQLSelect(string sqlcommand, string[,] parameters, int length)
{
try
{
conn = new SqlConnection(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString);
conn.Open();
SqlDataReader reader;
SqlCommand cmd = new SqlCommand(sqlcommand, conn);
var allLength = parameters.Length;
for (int i = 0; i < parameters.Length - length; i++)
{
string paramid = parameters[i, 0];
if (paramid == "@date" || paramid == "@Date" || paramid == "@DATE")
{
string paramvalue = parameters[i, 1];
DateTime date = Convert.ToDateTime(paramvalue);
paramvalue = date.ToString("yyyy-MM-dd HH':'mm':'ss");
cmd.Parameters.Add(new SqlParameter(paramid, paramvalue));
}
else
{
string paramvalue = parameters[i, 1];
cmd.Parameters.Add(new SqlParameter(paramid, paramvalue));
}
}
cmd.CommandType = CommandType.StoredProcedure;
reader = cmd.ExecuteReader();
return reader;
}
catch
{
return null;
}
}
这个函数是这样调用的
string[,] parameters = new string[1, 2] { { "@studentid", studentid } };
SqlDataReader reader = Common.SQLSelect(Common.tblstudentprogressselectforprinting, parameters, 1);
现在一切都运行良好,除了读取器仅包含 13 行数据,其中实际查询是
exec sp_tblstudentprogress_selectforprinting @studentid=N'87'
例如,返回 91 行。
我不知道为什么会这样。我唯一注意到的是,当使用SQL Server探查器时,从SQL Server运行查询时,有一个RPC:已启动和已完成,至于从我的Web应用程序中运行,只有一个RPC:已启动。
对此有什么想法吗?
编辑:
这是我枚举读者的方式
protected void btnPrint_Click(object sender, EventArgs e)
{
string[,] parameters = new string[1, 2] { { "@studentid", studentid } };
SqlDataReader reader = Common.SQLSelect(Common.tblstudentprogressselectforprinting, parameters, 1);
string firstname = txtFirstName.Text;
string lastname = txtLastName.Text;
int i=0;
string[] heading1 = new string[reader.FieldCount];
string[] heading2 = new string[reader.FieldCount];
string[] log = new string[reader.FieldCount];
try
{
while (reader.Read())
{
heading1[i] = "Progress Log for: Block: " + reader["block"].ToString() + " Lesson: " + reader["lesson"].ToString();
heading2[i] = "";
log[i] =
/*"PROGRESS LOG for " + reader["firstname"].ToString() + " " + reader["lastname"].ToString() + " Printed on " + DateTime.Today.ToShortDateString() + Environment.NewLine +*/
Environment.NewLine +
"Teacher: " + reader["teacher"].ToString() + Environment.NewLine +
"Date: " + reader["date"].ToString() + Environment.NewLine +
"Year: " + reader["year"].ToString() + Environment.NewLine +
"Block: " + reader["block"].ToString() + Environment.NewLine +
"Lesson: " + reader["lesson"].ToString() + Environment.NewLine +
"Warm Up: " + reader["warmup"].ToString() + Environment.NewLine +
"Range: " + reader["range"].ToString() + Environment.NewLine +
"Technique Sheet: " + reader["techniquesheet"].ToString() + Environment.NewLine +
"Technique Other: " + reader["techniqueother"].ToString() + Environment.NewLine +
Environment.NewLine +
"Notes: " + reader["notes"].ToString() + Environment.NewLine +
Environment.NewLine +
"Mark: " + reader["mark"].ToString()+ Environment.NewLine ;
i++;
}
}
catch
{
}
finally
{
if (Common.conn != null)
{
Common.conn.Close();
}
}
Common.PDFCreateProgressLog("Progress log for: " + firstname + " " + lastname, "Progress log for: " + firstname + " " + lastname, "PDF_" + firstname + " " + lastname + "-" + DateTime.Today.ToString("yyyy-MM-dd") + ".pdf", "Progress log for: " + firstname + " " + lastname, log, heading1, heading2);
}
您混淆了FieldCount
属性的含义。 它标识列数,而不是行数。 如果不先枚举所有行(无论如何至少枚举一次),则无法确定来自流式处理源(如 Reader)的行总数。
因此,每次从读取器读取一行并测试读取器以在不再有行时测试读取器时,您都需要扩展数组(列表可能更容易)。