我是一个新手，正如我的问题所证明的那样，我正在使用datareader来查找与某个subId值相关联的行。我使用了一个while（dr.read）循环并在每种情况下与其他读者嵌套了一个switch case语句（下面的代码），但我抛出了异常“已经是一个与此命令关联的开放数据读取器，必须首先关闭它”。有没有办法将第一个datareader的结果（subId = x的相关行）存储在数组或列表中，然后在我输入switch语句之前关闭该读取器？ （我理解数组是什么程度，我想它会起作用，但我不知道语法会是什么样子）。
string viewQuery = "SELECT ProductId FROM SubmissionProducts WHERE SubmissionId =" + x;
using (SqlCommand viewcmd = new SqlCommand(viewQuery, editConn))
{
SqlDataReader dr = viewcmd.ExecuteReader();
while (dr.Read())
{
switch(dr.GetInt32(0))
{
case 1:
PanelEplShow.Visible = true;
using (SqlCommand eplviewcmd = new SqlCommand(epl, editConn))
{
SqlDataReader epldr = eplviewcmd.ExecuteReader();
epldr.Read();
LblEplShowEntity.Text = epldr.GetString(0);
LblEplShowTotalEmpl.Text = epldr.GetInt32(1).ToString();
LblEplShowCalEmpl.Text = epldr.GetInt32(2).ToString();
LblEplShowMichEmpl.Text = epldr.GetInt32(3).ToString();
LblEplShowNyEmpl.Text = epldr.GetInt32(4).ToString();
LblEplShowNjEmpl.Text = epldr.GetInt32(5).ToString();
LblEplShowPrimEx.Text = epldr.GetInt32(6).ToString();
LblEplShowLim.Text = epldr.GetInt32(7).ToString();
LblEplShowPrem.Text = epldr.GetInt32(8).ToString();
LblEplShowWage.Text = epldr.GetInt32(9).ToString();
LblEplShowInvestCost.Text = epldr.GetInt32(10).ToString();
epldr.Close();
}
break;
case 2:
PanelProfShow.Visible = true;
using (SqlCommand profcmd1 = new SqlCommand(prof, editConn))
{
SqlDataReader profdr = profcmd1.ExecuteReader();
profdr.Read();
LblProfShowPrimEx.Text = profdr.GetInt32(0).ToString();
LblProfShowType.Text = profdr.GetInt32(1).ToString();
LblProfShowLim.Text = profdr.GetInt32(2).ToString();
LblProfShowRetention.Text = profdr.GetInt32(3).ToString();
LblProfShowAtt.Text = profdr.GetInt32(4).ToString();
LblProfShowPrem.Text = profdr.GetInt32(5).ToString();
LblProfShowSublim.Text = profdr.GetInt32(5).ToString();
LblProfShowEntity.Text = profdr.GetInt32(6).ToString();
profdr.Close();
}
break;
case 3:
PanelCrimeShow.Visible = true;
using (SqlCommand crimcmd = new SqlCommand(crim, editConn))
{
SqlDataReader crimdr = crimcmd.ExecuteReader();
crimdr.Read();
LblCrimeShowEntity.Text = crimdr.GetString(0);
LblCrimeShowEmpl.Text = crimdr.GetInt32(1).ToString();
LblCrimeShowPrimEx.Text = crimdr.GetInt32(2).ToString();
LblCrimeShowLimA.Text = crimdr.GetInt32(3).ToString();
LblCrimeShowDedA.Text = crimdr.GetInt32(4).ToString();
LblCrimeShowPremA.Text = crimdr.GetInt32(5).ToString();
LblCrimeShowLimB.Text = crimdr.GetInt32(6).ToString();
LblCrimeShowDedB.Text = crimdr.GetInt32(7).ToString();
LblCrimeShowPremB.Text = crimdr.GetInt32(8).ToString();
crimdr.Close();
}
break;
case 4:
PanelFidShow.Visible = true;
using (SqlCommand fidcmd = new SqlCommand(fid, editConn))
{
SqlDataReader fiddr = fidcmd.ExecuteReader();
fiddr.Read();
LblFidShowEntity.Text = fiddr.GetString(0);
LblFidShowPrimEx.Text = fiddr.GetInt32(1).ToString();
LblFidShowLim.Text = fiddr.GetInt32(2).ToString();
LblFidShowSir.Text = fiddr.GetInt32(3).ToString();
LblFidShowAtt.Text = fiddr.GetInt32(4).ToString();
LblFidShowPrem.Text = fiddr.GetInt32(5).ToString();
LblFidShowSublim.Text = fiddr.GetInt32(6).ToString();
fiddr.Close();
}
break;
case 5:
PanelNotShow.Visible = true;
using (SqlCommand notcmd = new SqlCommand(not, editConn))
{
SqlDataReader notdr = notcmd.ExecuteReader();
notdr.Read();
LblNotShowPrimEx.Text = notdr.GetInt32(0).ToString();
LblNotShowCov.Text = notdr.GetInt32(1).ToString();
LblNotShowSharedLim.Text = notdr.GetInt32(2).ToString();
LblNotShowTradLim.Text = notdr.GetInt32(3).ToString();
LblNotShowTradSir.Text = notdr.GetInt32(4).ToString();
LblNotShowEplLim.Text = notdr.GetInt32(5).ToString();
LblNotShowEplSir.Text = notdr.GetInt32(6).ToString();
LblNotShowEplPrem.Text = notdr.GetInt32(7).ToString();
LblNotShowSublim.Text = notdr.GetInt32(8).ToString();
notdr.Close();
}
break;
case 6:
PanelPrivShow.Visible = true;
using (SqlCommand privcmd = new SqlCommand(priv, editConn))
{
SqlDataReader privdr = privcmd.ExecuteReader();
privdr.Read();
LblPrivShowPrimEx.Text = privdr.GetInt32(0).ToString();
LblPrivShowSharedLim.Text = privdr.GetInt32(1).ToString();
LblPrivShowTradLim.Text = privdr.GetInt32(2).ToString();
LblPrivShowTradAtt.Text = privdr.GetInt32(3).ToString();
LblPrivShowTradSir.Text = privdr.GetInt32(4).ToString();
LblPrivShowTradPrem.Text = privdr.GetInt32(5).ToString();
LblPrivShowEplLim.Text = privdr.GetInt32(6).ToString();
LblPrivShowEplSir.Text = privdr.GetInt32(7).ToString();
LblPrivShowEplAtt.Text = privdr.GetInt32(8).ToString();
LblPrivShowEplPrem.Text = privdr.GetInt32(9).ToString();
LblPrivShowEplWage.Text = privdr.GetInt32(10).ToString();
LblPrivShowEplSublim.Text = privdr.GetInt32(11).ToString();
LblPrivShowFidLim.Text = privdr.GetInt32(12).ToString();
LblPrivShowFidSir.Text = privdr.GetInt32(13).ToString();
LblPrivShowFidAtt.Text = privdr.GetInt32(14).ToString();
LblPrivShowFidPrem.Text = privdr.GetInt32(15).ToString();
LblPrivShowFidSublim.Text = privdr.GetInt32(16).ToString();
privdr.Close();
}
break;
case 7:
PanelPubShow.Visible = true;
using (SqlCommand pubcmd = new SqlCommand(pub, editConn))
{
SqlDataReader pubdr = pubcmd.ExecuteReader();
pubdr.Read();
LblPubShowMark.Text = pubdr.GetInt32(0).ToString();
LblPubShowTick.Text = pubdr.GetInt32(1).ToString();
LblPubShowTrad.Text = pubdr.GetInt32(2).ToString();
LblPubShowDic.Text = pubdr.GetInt32(3).ToString();
LblPubShowLim.Text = pubdr.GetInt32(4).ToString();
LblPubShowSecSir.Text = pubdr.GetInt32(5).ToString();
LblPubShowAllSir.Text = pubdr.GetInt32(6).ToString();
LblPubShowPrem.Text = pubdr.GetInt32(7).ToString();
LblPubShowPrimEx.Text = pubdr.GetInt32(8).ToString();
LblPubShowAtt.Text = pubdr.GetInt32(9).ToString();
LblPubShowSublim.Text = pubdr.GetInt32(10).ToString();
pubdr.Close();
}
break;
default:
break;
}
}
dr.Close();`
答案 0 :(得分：15)
将其加载到DataTable。
SqlDataReader pubdr = pubcmd.ExecuteReader();
DataTable dt = new DataTable();
dt.Load(pubdr);
扩展评论：
foreach (DataRow dr in dt.Rows)
{
LblEplShowEntity.Text = dr["FIELDNAME"].ToString();
//...
}
答案 1 :(得分：3)
加载一个DataTable，无论如何内部都是持久化的DataReader
对于您使用，使用，丢弃的DataReader。这是DataReaders的本质。如果您想要数据闲置，您可以使用DataTable。简单，但是一个很好的经验法则。
答案 2 :(得分：2)
假设 SubmissionId 在表 SubmissionProducts 中是唯一的，您不需要使用数据读取器进行查询。您可以改为使用命令对象的ExecuteScalar方法。
如果要从DataReader获取当前行中所有collumn值的数组，可以使用GetValues方法，如下所示：
SqlDataReader reader; // assumming the data reader is already opened
object[] columns = new object[reader.FieldCount];
reader.GetValues(columns);// columns now contains all the values from the curent row
答案 3 :(得分：2)
我发现我必须在连接字符串中调整一些东西。我不知道它是否是一个.Net故障或者它是否只是在使用嵌套式阅读器时的必要调整，但我必须将MultipleActiveResultSets="true"添加到我存储的连接字符串中。之后，一切正常，不需要数据表。非常感谢所有回答的人。虽然我确信上面的答案也可以起作用，如果这个问题对未来的某个人有任何用处，我会发布完整的代码来展示对我有用的东西。 谨慎提醒：如果您有足够的新编码需要此帖子，请对您的查询进行PARAMETERIZE。这个网站是一个培训项目，我被要求避免参数化，以便先学习其他东西，但这是最重要的。 Bobby table ftw。
这是代码。
using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class View : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string x = Request.QueryString["SubmissionId"];
string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
string editCustQuery = "SELECT CustName, SicNaic, CustCity, CustAdd, CustState, CustZip FROM Customer WHERE SubId =" + x;
string editBroQuery = "SELECT BroName, BroAdd, BroCity, BroState, BroZip, EntityType FROM Broker WHERE SubId =" + x;
string editSubQuery = "SELECT Coverage, CurrentCoverage, PrimEx, Retention, EffectiveDate, Commission, Premium, Comments FROM Submission WHERE SubmissionId =" + x;
string epl = "SELECT Entity, Employees, CA, MI, NY, NJ, Primex, EplLim, EplSir, Premium, Wage, Sublim FROM EPL WHERE SubmissionId =" + x;
string prof = "SELECT Primex, EO, Limit, Retention, Att, Prem, Sublim, Entity FROM ProfessionalEO WHERE SubmissionId =" + x;
string crim = "SELECT Entity, Employees, PrimEx, LimA, DedA, PremA, LimitB, DedB, PremB FROM CrimeFidelity WHERE SubmissionId =" + x;
string fid = "SELECT Entity, PrimEx, Limit, SIR, Att, Premium, Sublim FROM Fiduciary WHERE SubmissionId =" + x;
string not = "SELECT PrimEx, Coverage, SharedSepLim, TradLim, TradDoSir, EplLim, EplSir, EplPrem, EplSublim FROM NotProfit WHERE SubmissionId =" + x;
string priv = "SELECT Primex, SharedSepLim, TradLim, TradAtt, TradDoSir, TradPrem, EplLim, EplSir, EplAtt, EplWage, EplPrem, EplInvest, FidLim, FidSir, FidAtt, FidPrem, FidSublim FROM PrivateCompany WHERE SubmissionId =" + x;
string pub = "SELECT Market, Ticker, TradABC, DIC, Limit, SecuritiesSir, OtherSir, Premium, PrimEx, Att, Sublim FROM PublicDO WHERE SubmissionId =" + x;
using (SqlConnection editConn = new SqlConnection(connectionString))
{
editConn.Open();
using (SqlCommand CustCommand = new SqlCommand(editCustQuery, editConn))
{
SqlDataReader dr = CustCommand.ExecuteReader();
dr.Read();
LblCustName.Text = dr.GetString(0);
LblSicNaic.Text = dr.GetString(1);
LblCustCity.Text = dr.GetString(2);
LblCustAddress.Text = dr.GetString(3);
LblCustState.Text = dr.GetString(4);
LblCustZip.Text = dr.GetInt32(5).ToString();
dr.Close();
}
using (SqlCommand BroCommand = new SqlCommand(editBroQuery, editConn))
{
SqlDataReader dr = BroCommand.ExecuteReader();
dr.Read();
LblBroName.Text = dr.GetString(0);
LblBroAddress.Text = dr.GetString(1);
LblBroCity.Text = dr.GetString(2);
LblBroState.Text = dr.GetString(3);
LblBroZip.Text = dr.GetInt32(4).ToString();
LblEntity.Text = dr.GetString(5);
dr.Close();
}
using (SqlCommand SubCommand = new SqlCommand(editSubQuery, editConn))
{
SqlDataReader dr = SubCommand.ExecuteReader();
dr.Read();
LblCoverage.Text = dr.GetInt32(0).ToString();
LblCurrentCoverage.Text = dr.GetInt32(1).ToString();
LblPrimEx.Text = dr.GetInt32(2).ToString();
LblRetention.Text = dr.GetInt32(3).ToString();
LblEffectDate.Text = dr.GetDateTime(4).ToString();
LblCommission.Text = dr.GetInt32(5).ToString();
LblPremium.Text = dr.GetInt32(6).ToString();
LblComments.Text = dr.GetString(7);
dr.Close();
HyperLink1.NavigateUrl = "~/ViewEdit.aspx?SubmissionId=" + x;
}
string viewQuery = "SELECT ProductId FROM SubmissionProducts WHERE SubmissionId =" + x;
SqlCommand viewcmd = new SqlCommand(viewQuery, editConn);
SqlDataReader drRows = viewcmd.ExecuteReader();
while (drRows.Read())
{
switch (drRows.GetInt32(0))
{
case 1:
PanelEplShow.Visible = true;
using (SqlCommand eplviewcmd = new SqlCommand(epl, editConn))
{
SqlDataReader epldr = eplviewcmd.ExecuteReader();
epldr.Read();
LblEplShowEntity.Text = epldr.GetString(0);
LblEplShowTotalEmpl.Text = epldr.GetInt32(1).ToString();
LblEplShowCalEmpl.Text = epldr.GetInt32(2).ToString();
LblEplShowMichEmpl.Text = epldr.GetInt32(3).ToString();
LblEplShowNyEmpl.Text = epldr.GetInt32(4).ToString();
LblEplShowNjEmpl.Text = epldr.GetInt32(5).ToString();
LblEplShowPrimEx.Text = epldr.GetInt32(6).ToString();
LblEplShowLim.Text = epldr.GetInt32(7).ToString();
LblEplShowSir.Text = epldr.GetInt32(8).ToString();
LblEplShowPrem.Text = epldr.GetInt32(9).ToString();
LblEplShowWage.Text = epldr.GetInt32(10).ToString();
LblEplShowInvestCost.Text = epldr.GetInt32(11).ToString();
epldr.Close();
}
break;
case 2:
PanelProfShow.Visible = true;
using (SqlCommand profcmd = new SqlCommand(prof, editConn))
{
SqlDataReader profdr = profcmd.ExecuteReader();
profdr.Read();
LblProfShowPrimEx.Text = profdr.GetInt32(0).ToString();
LblProfShowType.Text = profdr.GetString(1);
LblProfShowLim.Text = profdr.GetInt32(2).ToString();
LblProfShowRetention.Text = profdr.GetInt32(3).ToString();
LblProfShowAtt.Text = profdr.GetInt32(4).ToString();
LblProfShowPrem.Text = profdr.GetInt32(5).ToString();
LblProfShowSublim.Text = profdr.GetInt32(6).ToString();
LblProfShowEntity.Text = profdr.GetString(7);
profdr.Close();
}
break;
case 3:
PanelCrimeShow.Visible = true;
using (SqlCommand crimcmd = new SqlCommand(crim, editConn))
{
SqlDataReader crimdr = crimcmd.ExecuteReader();
crimdr.Read();
LblCrimeShowEntity.Text = crimdr.GetString(0);
LblCrimeShowEmpl.Text = crimdr.GetInt32(1).ToString();
LblCrimeShowPrimEx.Text = crimdr.GetInt32(2).ToString();
LblCrimeShowLimA.Text = crimdr.GetInt32(3).ToString();
LblCrimeShowDedA.Text = crimdr.GetInt32(4).ToString();
LblCrimeShowPremA.Text = crimdr.GetInt32(5).ToString();
LblCrimeShowLimB.Text = crimdr.GetInt32(6).ToString();
LblCrimeShowDedB.Text = crimdr.GetInt32(7).ToString();
LblCrimeShowPremB.Text = crimdr.GetInt32(8).ToString();
crimdr.Close();
}
break;
case 4:
PanelFidShow.Visible = true;
using (SqlCommand fidcmd = new SqlCommand(fid, editConn))
{
SqlDataReader fiddr = fidcmd.ExecuteReader();
fiddr.Read();
LblFidShowEntity.Text = fiddr.GetString(0);
LblFidShowPrimEx.Text = fiddr.GetInt32(1).ToString();
LblFidShowLim.Text = fiddr.GetInt32(2).ToString();
LblFidShowSir.Text = fiddr.GetInt32(3).ToString();
LblFidShowAtt.Text = fiddr.GetInt32(4).ToString();
LblFidShowPrem.Text = fiddr.GetInt32(5).ToString();
LblFidShowSublim.Text = fiddr.GetInt32(6).ToString();
fiddr.Close();
}
break;
case 5:
PanelNotShow.Visible = true;
using (SqlCommand notcmd = new SqlCommand(not, editConn))
{
SqlDataReader notdr = notcmd.ExecuteReader();
notdr.Read();
LblNotShowPrimEx.Text = notdr.GetInt32(0).ToString();
LblNotShowCov.Text = notdr.GetInt32(1).ToString();
LblNotShowSharedLim.Text = notdr.GetInt32(2).ToString();
LblNotShowTradLim.Text = notdr.GetInt32(3).ToString();
LblNotShowTradSir.Text = notdr.GetInt32(4).ToString();
LblNotShowEplLim.Text = notdr.GetInt32(5).ToString();
LblNotShowEplSir.Text = notdr.GetInt32(6).ToString();
LblNotShowEplPrem.Text = notdr.GetInt32(7).ToString();
LblNotShowSublim.Text = notdr.GetInt32(8).ToString();
notdr.Close();
}
break;
case 6:
PanelPrivShow.Visible = true;
using (SqlCommand privcmd = new SqlCommand(priv, editConn))
{
SqlDataReader privdr = privcmd.ExecuteReader();
privdr.Read();
LblPrivShowPrimEx.Text = privdr.GetInt32(0).ToString();
LblPrivShowSharedLim.Text = privdr.GetInt32(1).ToString();
LblPrivShowTradLim.Text = privdr.GetInt32(2).ToString();
LblPrivShowTradAtt.Text = privdr.GetInt32(3).ToString();
LblPrivShowTradSir.Text = privdr.GetInt32(4).ToString();
LblPrivShowTradPrem.Text = privdr.GetInt32(5).ToString();
LblPrivShowEplLim.Text = privdr.GetInt32(6).ToString();
LblPrivShowEplSir.Text = privdr.GetInt32(7).ToString();
LblPrivShowEplAtt.Text = privdr.GetInt32(8).ToString();
LblPrivShowEplPrem.Text = privdr.GetInt32(9).ToString();
LblPrivShowEplWage.Text = privdr.GetInt32(10).ToString();
LblPrivShowEplSublim.Text = privdr.GetInt32(11).ToString();
LblPrivShowFidLim.Text = privdr.GetInt32(12).ToString();
LblPrivShowFidSir.Text = privdr.GetInt32(13).ToString();
LblPrivShowFidAtt.Text = privdr.GetInt32(14).ToString();
LblPrivShowFidPrem.Text = privdr.GetInt32(15).ToString();
LblPrivShowFidSublim.Text = privdr.GetInt32(16).ToString();
privdr.Close();
}
break;
case 7:
PanelPubShow.Visible = true;
using (SqlCommand pubcmd = new SqlCommand(pub, editConn))
{
SqlDataReader pubdr = pubcmd.ExecuteReader();
pubdr.Read();
LblPubShowMark.Text = pubdr.GetInt32(0).ToString();
LblPubShowTick.Text = pubdr.GetInt32(1).ToString();
LblPubShowTrad.Text = pubdr.GetInt32(2).ToString();
LblPubShowDic.Text = pubdr.GetString(3);
LblPubShowLim.Text = pubdr.GetInt32(4).ToString();
LblPubShowSecSir.Text = pubdr.GetInt32(5).ToString();
LblPubShowAllSir.Text = pubdr.GetInt32(6).ToString();
LblPubShowPrem.Text = pubdr.GetInt32(7).ToString();
LblPubShowPrimEx.Text = pubdr.GetInt32(8).ToString();
LblPubShowAtt.Text = pubdr.GetInt32(9).ToString();
LblPubShowSublim.Text = pubdr.GetInt32(10).ToString();
pubdr.Close();
}
break;
default:
break;
}
}
drRows.Close();
}
}
}