您好，我開發了用于監控 Oracle 資料庫的 BackgroundService，當新記錄插入源表時，將記錄復制到 SQL Server 資料庫中。但過了一段時間（有時 1 天，有時 2 天）。我的服務已停止作業。錯誤提示：“任務已取消”。我不明白為什么我的代碼突然停止作業。
注意：我在 IIS 上托管的應用程式 (Windows Server 2012)
- 我想無休止地運行我的應用程式。
這是我的代碼：
public class MainTransactionService : BackgroundService
{
private readonly ILogger Logger;
private readonly TransactionSettings TSettings;
public MainTransactionService(ILogger logger, TransactionSettings tSettings)
{
TSettings = tSettings;
Logger = logger;
}
protected async override Task ExecuteAsync(CancellationToken stoppingToken)
{
//Create a connection to Oracle
string conString = "";
//How to connect to an Oracle DB without SQL*Net configuration file
// also known as tnsnames.ora.
//"Data Source=orclpdb";
"Data Source=eoffice";
OracleConfiguration.OracleDataSources.Add("eoffice", "");
//How to connect to an Oracle DB with a DB alias.
//Uncomment below and comment above.
//"Data Source=<service name alias>;";
OracleConnection con = new OracleConnection(conString);
Logger.Information("Connected to Oracle");
OracleCommand cmd = con.CreateCommand();
try
{
Logger.Information("Run part executed");
if (con.State != ConnectionState.Open)
{
con.Open();
}
while (!stoppingToken.IsCancellationRequested)
{
await Task.Delay(TSettings.Frequency, stoppingToken);
//Logger.Information(stoppingToken.IsCancellationRequested.ToString());
try
{
var cancelTask = Task.Delay(TSettings.Timeout, stoppingToken);
//Logger.Information("CODE EXECUTED");
//await context.Response.WriteAsync("Server is Listening");
//OracleConfiguration.OracleDataSources.Add("orclpdb", "(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = miatdw1.miat.com.mn)(PORT = 1521)))(CONNECT_DATA = (SERVICE_NAME = orclpdb.miat.com.mn)))");
//Check Oracle
Logger.Information("Establishing Oracle Connection (While)");
cmd.CommandText = "select MAX(id) from PB_TRANSACTION";
int SourceTableMaxId = Convert.ToInt32(cmd.ExecuteScalar());
//Check SQL
SqlConnection conn = new SqlConnection("");
SqlCommand check_id = new SqlCommand("select MAX(id) from PB_TRANSACTION", conn);
Logger.Information("Establishing MS-SQL Connection");
conn.Open();
int TargetTableMaxId = Convert.ToInt32(check_id.ExecuteScalar());
if (SourceTableMaxId > TargetTableMaxId)
{
int TotalNewRecords = SourceTableMaxId - TargetTableMaxId;
Logger.Information(TotalNewRecords.ToString() " New Records Found");
OracleCommand command = new OracleCommand();
command.CommandText = "select * from (select * from pb_transaction order by id desc) x where ROWNUM <= :lastrecord";
command.Parameters.Add(":username", OracleDbType.Int32).Value = TotalNewRecords;
command.Connection = con;
Logger.Information("Retrieved " TotalNewRecords.ToString() " from PB_TRANSACTION table.");
Transaction LastTransaction = new Transaction();
using (OracleDataReader oReader = command.ExecuteReader())
{
while (oReader.Read())
{
LastTransaction.Id = Convert.ToInt32(oReader["ID"]);
LastTransaction.type = oReader["TYPE"].ToString();
LastTransaction.account = oReader["ACCOUNT"].ToString();
LastTransaction.journal_id = oReader["JOURNAL_ID"].ToString();
LastTransaction.amount = Convert.ToDouble(oReader["AMOUNT"]);
LastTransaction.currency = oReader["CURRENCY"].ToString();
LastTransaction.posted_date = oReader["POSTED_DATE"].ToString();
LastTransaction.statement_date = oReader["STATEMENT_DATE"].ToString();
LastTransaction.description = oReader["DESCRIPTION"].ToString();
LastTransaction.pnr = oReader["PNR"].ToString();
LastTransaction.pnr_approved = Convert.ToInt32(oReader["PNR_APPROVED"]);
LastTransaction.jid = oReader["JID"].ToString();
LastTransaction.user_id = oReader["USER_ID"].ToString();
LastTransaction.inserted_date = oReader["INSERTED_DATE"].ToString();
SqlCommand scmd = new SqlCommand("insert into PB_TRANSACTION (ID,TYPE, ACCOUNT, JOURNAL_ID, AMOUNT, CURRENCY, POSTED_DATE, STATEMENT_DATE, DESCRIPTION, PNR, PNR_APPROVED, JID, USER_ID, INSERTED_DATE) values(@id,@type,@account,@journalid, @amount,@currency,@posteddate,@statementdate,@description,@pnr,@pnrapproved,@jid,@userid,@inserteddate);", conn);
scmd.Parameters.AddWithValue("@id", LastTransaction.Id);
scmd.Parameters.AddWithValue("@type", LastTransaction.type);
scmd.Parameters.AddWithValue("@account", LastTransaction.account);
scmd.Parameters.AddWithValue("@journalid", LastTransaction.journal_id);
scmd.Parameters.AddWithValue("@amount", LastTransaction.amount);
scmd.Parameters.AddWithValue("@currency", LastTransaction.currency);
scmd.Parameters.AddWithValue("@posteddate", LastTransaction.posted_date);
scmd.Parameters.AddWithValue("@statementdate", LastTransaction.statement_date);
scmd.Parameters.AddWithValue("@description", LastTransaction.description);
scmd.Parameters.AddWithValue("@pnr", LastTransaction.pnr);
scmd.Parameters.AddWithValue("@pnrapproved", LastTransaction.pnr_approved);
scmd.Parameters.AddWithValue("@jid", LastTransaction.jid);
scmd.Parameters.AddWithValue("@userid", LastTransaction.user_id);
scmd.Parameters.AddWithValue("@inserteddate", LastTransaction.inserted_date);
scmd.ExecuteNonQuery();
}
Logger.Information(TotalNewRecords.ToString() " records inserted");
}
}
else
{
Logger.Information("No New Records found");
}
}
catch (Exception ex)
{
LogError("INNER TRY: " ex.Message);
}
}
Logger.Information("Oracle Database connection has successfully Disconnected!!!");
}
catch (TaskCanceledException tex)
{
LogError("TASK ERROR: " tex.Message);
}
catch (Exception ex)
{
LogError("MAIN ERROR: " ex.Message);
}
finally
{
con.Close();
con.Dispose();
}
}
public async override Task StopAsync(CancellationToken cancellationToken)
{
await base.StopAsync(cancellationToken);
}
private void LogError(string error)
{
Logger.Error(error);
}
}
uj5u.com熱心網友回復：
我在 IIS 上托管的應用程式（Windows Server 2012）
我想無休止地運行我的應用程式。
BackgroundService只要您的 ASP.NET 應用程式運行，托管在 IIS 中的 ASP.NET 就會運行。而已。由于 ASP.NET/IIS 將定期重新啟動，因此您BackgroundService將定期關閉（并重新啟動）。ASP.NET 和 IIS 都不是為長期后臺行程而設計的；它們是為 HTTP 服務設計的。在一般情況下（即云提供商），您的應用程式實際上可能會關閉，直到下一個 HTTP 請求進來。
如果這是不可接受的，那么 ASP.NET/IIS 不是您需要的正確主機。您可以使用 Win32 服務主機而不是 ASP.NET/IIS，方法是使用 Worker Service 模板創建一個新專案，添加一個 Win32 服務生命周期，并將其托管BackgroundService在該應用程式而不是 ASP.NET 應用程式中。
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標籤：C＃ asp.net 核心 .net-core iis 后台服务
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