通过保存为数据表的一系列循环和数据库调用（仅限 Select 语句），我正在生成一个包含这些值的 .txt 文件。它运行了一会儿（19行......19个完整循环周期）然后我得到一个运行时异常被connection.Open（）
我将整个循环放在一个 try catch 块中，以便捕获异常并生成消息，然后是 2 个空行，然后是堆栈跟踪。
我试图阅读这篇文章并弄清楚该怎么做，但在数据库连接方面我有点新手。我在别处看过，但似乎没有找到一个非常适合我情况的问题。
仅供参考：C# 4.0 Windows 窗体应用程序，Access DB
我希望找到一些关于从哪里开始寻找的建议。我很肯定，由于我实施的验证而引发此错误时，我的连接已关闭，如下所示：
internal IDbConnection GetConnection()
{
try
{
var connection = _assemblyProvider.Factory.CreateConnection();
connection.ConnectionString = _connectionString;
_connectionState = connection.State.ToString();
if (_connectionState == "Open")
GetConnection();
else
{
connection.Open();
}
return connection;
}
catch (Exception exept)
{
throw new Exception(exept.ToString() + "\n\n" + exept.StackTrace.ToString());
}
}
正在从这里调用此方法：
public DataTable ExecuteDataTable(string commandText, string tableName, DbParameterCollection paramCollection, CommandType commandType)
{
DataTable dtReturn;
IDbConnection connection = null;
try
{
connection = _connectionManager.GetConnection();
dtReturn = _dbAdapterManager.GetDataTable(commandText, paramCollection, connection, tableName, commandType);
}
finally
{
if (connection != null)
{
connection.Close();
connection.Dispose();
}
}
return dtReturn;
}
public DataTable ExecuteDataTable(string commandText, string tableName, CommandType commandType)
{
return ExecuteDataTable(commandText, tableName, new DbParameterCollection(), commandType);
}
public DataTable ExecuteDataTable(string commandText)
{
return ExecuteDataTable(commandText, string.Empty, CommandType.Text);
}
和
//read from DB using a SQL statement and return a DataTable
internal static DataTable readDB(string SQL)
{
var dbHelper = new DbHelper();
using (IDbConnection connection = dbHelper.GetConnObject())
{
return dbHelper.ExecuteDataTable(SQL);
}
}
这是循环（它有点长，可能会做得更好，但我只是想找出为什么它在多次工作后会中断）
异常从以下行引发：
DataTable iRecNum2ClaimRecNumFromClaim = dbConnect.readDB(SQLString);
在这里面：
SQLString = "SELECT * FROM Claim WHERE ClaimStatus <> 1";
DataTable allRecsFromClaimNotStatus1 = dbConnect.readDB(SQLString);
if (allRecsFromClaimNotStatus1.Rows.Count == 0)
return;
else
{
string path = txtExtractFileLocation.Text;
if (txtExtractFileLocation.Text.Substring(txtExtractFileLocation.Text.Length - 2) == "\\\\")
{
path = path.Substring(0, path.Length - 1);
}
if (path.Substring(path.Length - 1) == "\\")
path += "DI_Extract.txt";
else
path += @"\DI_Extract.txt";
using (StreamWriter sw = new StreamWriter(@path))
{
for (int i = 0; i < allRecsFromClaimNotStatus1.Rows.Count; i++)
{
rNum = allRecsFromClaimNotStatus1.Rows[i][2].ToString().Trim();//Claim.InsuredRecNum
SQLString = "SELECT * FROM Insured WHERE RecNum = " + rNum;
DataTable allInsuredByRecNum = dbConnect.readDB(SQLString);
lossDate = allRecsFromClaimNotStatus1.Rows[i][11].ToString().Trim();//Claim.LossDate
lossDate = (Convert.ToDateTime(lossDate)).Date.ToString("MM/dd/yyyy");
reportedDate = allRecsFromClaimNotStatus1.Rows[i][9].ToString().Trim();//Claim.ReportedDate
reportedDate = (Convert.ToDateTime(reportedDate)).Date.ToString("MM/dd/yyyy");
claim = allRecsFromClaimNotStatus1.Rows[i][0].ToString().Trim();//Claim.ClaimNumber
if (chkIncludePaymentsForCurrentMonth.Checked == true)
{
direct = allRecsFromClaimNotStatus1.Rows[i][4].ToString().Trim();//Claim.DirectReserve
WP = allRecsFromClaimNotStatus1.Rows[i][5].ToString().Trim();//Claim.WPReserve
ceded = allRecsFromClaimNotStatus1.Rows[i][6].ToString().Trim();//Claim.CededReserve
}
else
{
direct = allRecsFromClaimNotStatus1.Rows[i][29].ToString().Trim();//Claim.MonthEndDirect
WP = allRecsFromClaimNotStatus1.Rows[i][30].ToString().Trim();//Claim.MonthEndWP
ceded = allRecsFromClaimNotStatus1.Rows[i][31].ToString().Trim();//Claim.MonthEndCeded
}
ced = Convert.ToDecimal(ceded);
wav = Convert.ToDecimal(WP);
ceded = ced.ToString("#.##");
WP = wav.ToString("#.##");
if (ceded == "")
ceded = "0";
if (WP == "")
WP = "0";
if ((allRecsFromClaimNotStatus1.Rows[i][10].ToString().Trim() != null) &&
(allRecsFromClaimNotStatus1.Rows[i][10].ToString().Trim() != ""))//Claim.WaiverDate
{
onWaiver = "YES";
}
else
{
onWaiver = "NO";
}
reinsPreNotice = "NO";
reinsCeded = "NO";
switch (allRecsFromClaimNotStatus1.Rows[i][7].ToString().Trim())//Claim.CededPre
{
case "1":
{
reinsPreNotice = "YES";
break;
}
case "2":
{
reinsCeded = "YES";
break;
}
}//end switch
state = allRecsFromClaimNotStatus1.Rows[i][8].ToString().Trim();//Claim.LossState
lName = allInsuredByRecNum.Rows[0][1].ToString().Trim();//Insured.LastName
fName = allInsuredByRecNum.Rows[0][0].ToString().Trim();//Insured.FirstName
mi = allInsuredByRecNum.Rows[0][2].ToString().Trim();//Insured.MI
policy = allInsuredByRecNum.Rows[0][43].ToString().Trim();//Insured.PolicyNumber
DOB = allInsuredByRecNum.Rows[0][10].ToString().Trim();//Insured.DOB
DOB = (Convert.ToDateTime(DOB)).Date.ToString("MM/dd/yyyy");
age = allInsuredByRecNum.Rows[0][11].ToString().Trim();//Insured.TrueAge
issueAge = calculateAge(Convert.ToDateTime(allInsuredByRecNum.Rows[0][10].ToString().Trim()), //Insured.DOB
Convert.ToDateTime(allInsuredByRecNum.Rows[0][45].ToString().Trim()));//Insured.EffectiveDate
SQLString = "SELECT InsuredRecNum, RecNum FROM Claim WHERE InsuredRecNum = " + rNum;
DataTable iRecNum2ClaimRecNumFromClaim = dbConnect.readDB(SQLString);
rNum = iRecNum2ClaimRecNumFromClaim.Rows[0][1].ToString().Trim();
issueDate = allInsuredByRecNum.Rows[0][45].ToString().Trim();//Insured.EffectiveDate
issueDate = (Convert.ToDateTime(issueDate)).Date.ToString("MM/dd/yyyy");
sex = allInsuredByRecNum.Rows[0][13].ToString().Trim();//Insured.Gender
planCode = allInsuredByRecNum.Rows[0][44].ToString().Trim();//Insured.PlanMnemonic
issueAmt = allInsuredByRecNum.Rows[0][49].ToString().Trim();//Insured.BenefitAmount (Monthly Benefit Amount before Offset)
benefitPeriod = allInsuredByRecNum.Rows[0][50].ToString().Trim();//Insured.BenefitPeriod
if (allInsuredByRecNum.Rows[0][54].ToString().Trim().Length == 2)//Insured.EliminationPeriod
eliminationPeriod = "0" + allInsuredByRecNum.Rows[0][54].ToString().Trim();
else
eliminationPeriod = allInsuredByRecNum.Rows[0][54].ToString().Trim();
premiumAmount = allInsuredByRecNum.Rows[0][48].ToString().Trim();//Insured.AnnualPremium
occupationClass = allInsuredByRecNum.Rows[0][55].ToString().Trim();//Insured.OccupationClass
//select only status = EXEC (0)
SQLString = "SELECT * FROM Offset WHERE ClaimRecNum = " + rNum + " AND Status = 0";
DataTable allOffsetByClaimRecNumAndStatus0 = dbConnect.readDB(SQLString);
offsetAmt = 0;
dblSTDOffsetAmount = 0;
dblRecOffsetAmount = 0;
RECOffsetOcc = "0";
RECOffsetExecuted = "0";
int offsetCount = allOffsetByClaimRecNumAndStatus0.Rows.Count;
if (offsetCount != 0)
{
for (int j = 0; j < offsetCount; j++)
{
//accumulate standard offset (STD) and Recovery offset (REC)
if (allOffsetByClaimRecNumAndStatus0.Rows[0][1].ToString().Trim() == "0")//Offset.Type
{
//Standard Type
dblSTDOffsetAmount += Convert.ToDouble(allOffsetByClaimRecNumAndStatus0.Rows[j][4].ToString().Trim());//Offset.Amount
}
else
{
//Recovery type
dblRecOffsetAmount = Convert.ToDouble(allOffsetByClaimRecNumAndStatus0.Rows[j][4].ToString().Trim());//Offset.Amount
RECOffsetOcc = allOffsetByClaimRecNumAndStatus0.Rows[j][5].ToString().Trim();//Offset.Occurance
RECOffsetExecuted = allOffsetByClaimRecNumAndStatus0.Rows[j][6].ToString().Trim();//Offset.Executed
}//end if
}//end for loop
}//end if
STDOffsetAmount = dblSTDOffsetAmount.ToString();
RECOffsetAmount = dblRecOffsetAmount.ToString();
if (chkIncludePaymentsForCurrentMonth.Checked == true)
SQLString = "SELECT * FROM Payment WHERE InsuredRecNum = " + rNum + " AND IssueDate >= #01/01/" + DateTime.Today.Date.Year + "# AND IssueDate <= #" + DateTime.Today.Date.ToShortDateString() + "#";
else
SQLString = "SELECT * FROM Payment WHERE InsuredRecNum = " + rNum + " AND IssueDate >= #01/01/" + endDate.Substring(endDate.Length - 4) + "# AND IssueDate <= #" + Convert.ToDateTime(endDate).Date.ToShortDateString() + "#";
DataTable allPaymentByIRecNumAndIssDateInRange = dbConnect.readDB(SQLString);
YTDPmt = 0;
if (allPaymentByIRecNumAndIssDateInRange.Rows.Count == 0)
YTDPmt = 0;
else
{
int paymentCount = allPaymentByIRecNumAndIssDateInRange.Rows.Count;
double issAmt;
for (int k = 0; k < paymentCount; k++)
{
issAmt = Convert.ToDouble(allPaymentByIRecNumAndIssDateInRange.Rows[0][30].ToString().Trim());//Payment.IssueAmount
YTDPmt += issAmt;
}// end loop
}//end if
YTDPmts = YTDPmt.ToString();
if (chkIncludePaymentsForCurrentMonth.Checked == true)
SQLString = "SELECT * FROM Payment WHERE ClaimRecNum = " + rNum;
else
SQLString = "SELECT * FROM Payment WHERE ClaimRecNum = " + rNum + " AND IssueDate <= #" + Convert.ToDateTime(endDate).Date.ToShortDateString() + "#";
DataTable allPaymentByRNum = dbConnect.readDB(SQLString);
totalPmt = 0;
if (allPaymentByRNum.Rows.Count == 0)
totalPmt = 0;
else
{
double issAmt = Convert.ToDouble(allPaymentByRNum.Rows[0][30].ToString().Trim());
for (int m = 0; m < allPaymentByRNum.Rows.Count; m++)
{
totalPmt += issAmt;
}
}
allPmts = totalPmt.ToString();
//set spacing for output
string block1 = policy + claim + planCode;
block1 = setSpacing(block1, 28);
string block2 = setSpacing(benefitPeriod, 3) + eliminationPeriod + occupationClass;
block2 = setSpacing(block2, 11);
issueAmt = setSpacing(issueAmt, 8);
STDOffsetAmount = setSpacing(STDOffsetAmount, 8);
RECOffsetAmount = setSpacing(RECOffsetAmount, 8);
RECOffsetOcc = setSpacing(RECOffsetOcc, 3);
RECOffsetExecuted = setSpacing(RECOffsetExecuted, 3);
string block3 = lossDate + age;
block3 = setSpacing(block3, 13);
issueAge = setSpacing(issueAge, 3);
string block4 = issueDate + DOB + sex + onWaiver + premiumAmount;
block4 = setSpacing(block4, 32);
reinsPreNotice = setSpacing(reinsPreNotice, 3);
reinsCeded = setSpacing(reinsCeded, 4);
double ap = Convert.ToDouble(allPmts);
allPmts = ap.ToString("#.#");
allPmts = setSpacing(allPmts, 8);
YTDPmts = setSpacing(YTDPmts, 8);
lName = setSpacing(lName, 19);
fName = fName + " " + mi;
fName = setSpacing(fName, 20);
string block5 = state + direct;
block5 = setSpacing(block5, 10);
ceded = setSpacing(ceded, 8);
WP = setSpacing(WP, 8);
reportedDate = setSpacing(reportedDate, 10);
//save row data for text file
dataOutput = (block1 + block2 + issueAmt + STDOffsetAmount + RECOffsetAmount + RECOffsetOcc + RECOffsetExecuted +
block3 + issueAge + block4 + reinsPreNotice + reinsCeded + allPmts + YTDPmts + lName + fName +
block5 + ceded + WP + reportedDate);
//Write to the output record DI_Extract.txt
sw.WriteLine(dataOutput);
counter++;
pbrRecordsProcessed.Value = counter;
}//end for loop
}//end streamwriter
}//end if