C# C-连接始终打开-如何打开/关闭
我需要一些申请方面的帮助。 该应用程序正在全天候运行，但如果与数据库的连接丢失，则该应用程序将不再工作——它只是停止 看起来连接从未关闭过，但我不知道为什么 是否有可能使此应用程序对数据库脱机更加健壮？ 怎么办：哦C# C-连接始终打开-如何打开/关闭,c#,connection,C#,Connection,我需要一些申请方面的帮助。 该应用程序正在全天候运行，但如果与数据库的连接丢失，则该应用程序将不再工作——它只是停止 看起来连接从未关闭过，但我不知道为什么 是否有可能使此应用程序对数据库脱机更加健壮？ 怎么办：哦 using System; using System.Collections; using System.Collections.Generic; using System.ComponentModel; using System.Data;
using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.IO;
using System.Text;
using System.Windows.Forms;
using System.Xml;
using System.Windows;
using System.Runtime;
using System.Drawing.Printing;
using cs_IniHandlerDevelop;
namespace AlServ_Batch
{
public partial class Batch_MainForm : Form
{
public Batch_MainForm()
{
InitializeComponent();
}
private void Batch_MainForm_Load(object sender, EventArgs e)
{
UpdateStatusLight();
}
private void UpdateStatusLight() {
ConnectionState st = Connection.State;
if (st == ConnectionState.Open
|| st == ConnectionState.Fetching
|| st == ConnectionState.Executing
)
{
pictureBox1.Image = Properties.Resources.greenlight;
}
else if (st == ConnectionState.Closed || st == ConnectionState.Broken)
{
pictureBox1.Image = Properties.Resources.redlight;
}
else
{
pictureBox1.Image = Properties.Resources.yellowlight;
}
}
public static string[] TextTypeName = new string[] { "",
"Portvagt/I normal arbejdstid",
"TDA/I normal arbejdstid underret",
"Portvagt/Uden for normal arbejdstid",
"TDA/Uden for normal arbejdstid",
"Procedure",
"Anlæg og følerplacering",
"Særlige forhold",
"Betjeningsområde", //***//
"Anden instruktion (SOP/BPP)",
"System Alarm"}; //***//
public static string[] TextFieldName = new string[] { "",
"workcall", "workinform", "offcall", "offinform", "procedur",
"plant", "turnoff", "position", "instruction", "restart" };
private int timerLevel = 0;
private void timer1_Tick(object sender, EventArgs e)
{
if (timerLevel == 0)
{
timerLevel++;
try
{
UpdateStatusLight();
ProcessBatch();
}
catch { }
timerLevel--;
}
}
private void ProcessBatch()
{
if (Connection.State == ConnectionState.Open)
{
{
String sql = "select recid,action,parm1,parm2,parm3,parm4,targetfile from alarm.batch where recid>0 order by recid";
OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(sql, Connection);
OleDbDataReader reader = cmd.ExecuteReader();
if (reader.Read())
{
int n = 0;
string recid_str = reader[n++].ToString();
string action = reader[n++].ToString();
string parm1 = reader[n++].ToString();
string parm2 = reader[n++].ToString();
string parm3 = reader[n++].ToString();
string parm4 = reader[n++].ToString();
string targetfile = reader[n++].ToString();
sql = "update alarm.batch set recid= -" + recid_str + " where recid=" + recid_str;
cmd = new System.Data.OleDb.OleDbCommand(sql, Connection);
cmd.ExecuteNonQuery();
if (ProcessBatchItem(action, parm1, parm2, parm3, parm4, targetfile))
{
sql = "delete from alarm.batch where recid= -" + recid_str;
cmd = new System.Data.OleDb.OleDbCommand(sql, Connection);
cmd.ExecuteNonQuery();
}
}
reader.Close();
}
}
}
private bool ProcessBatchItem(string action, string parm1, string parm2, string parm3, string parm4, string targetfile)
{
DateTime waituntil;
bool res = true;
bool liveAlarm = false;
string fname = "";
string fnameTemp;
string targetPrinters = "";
if (targetfile.ToString().Length>0) {
fname = Path.Combine(Properties.Settings.Default.htmlprintpath, targetfile);
}
TextWriter tw;
if (fname == "") fname = (new Random()).Next(int.MaxValue) + "__" + (new Random()).Next(int.MaxValue) + ".htm";
fnameTemp = fname + "_";
tw = new StreamWriter(fnameTemp);
string htmlPrefix = "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">"
;
AlarmInstruction instruction = new AlarmInstruction();
if (action == "print")
{
liveAlarm = (parm4=="ALARM");
instruction = new AlarmInstruction(int.Parse(parm1), Connection);
targetPrinters = instruction.TargetPrinters;
WriteAlarmInstruction(tw, instruction, parm3+(targetPrinters.Length>0 ? " ("+targetPrinters+")":""), parm2.ToString()=="1", parm4, htmlPrefix+"<body charset=windows-1252>", "</body>");
tw.Close();
}
else if (action == "printmany")
{
WriteAlarmInstructions(tw, parm1,parm3,parm4,htmlPrefix+"<body charset=windows-1252>", "</body>");
liveAlarm = false; // (parm4 == "ALARM");
tw.Close();
}
System.IO.File.Move(fnameTemp, fname);
if (liveAlarm || true) {
string ts = DateTime.Now.ToString();
bool busy = true;
StreamReader reader = new StreamReader(fname);
string docText = reader.ReadToEnd();
foreach (char ch in targetPrinters)
{
try
{
int n = int.Parse(ch.ToString());
n = n == 0 ? 10 : n;
if (n > 0 && n <= 10)
{
HtmlPrint(docText, instruction.PrinterName(n));
}
}
catch
{
}
}
foreach (string mobile in instruction.SmsTarget.Split(new char[] { ';'}))
{
try
{
string smsDir = instruction.Ini.GetValue("Directory", "Sms");
string footer = instruction.Ini.GetValue("Sms", "Footer");
fname = smsDir + "\\" + DateTime.Now.Ticks.ToString();
fnameTemp = fname + ".$$$";
tw = new StreamWriter(fnameTemp);
tw.WriteLine(mobile);
tw.WriteLine();
tw.WriteLine(parm3);
tw.WriteLine(instruction.UserAdr);
tw.WriteLine(instruction.Caption);
tw.WriteLine(footer);
tw.Close();
File.Move(fnameTemp, fname + ".txt");
}
catch (Exception e)
{
}
}
}
waituntil = DateTime.Now.AddSeconds(2);
while (DateTime.Now < waituntil) Application.DoEvents();
return res;
}
private void HtmlPrint(string doctext, string printerName)
{
Batch_BrowserForm browserForm = new Batch_BrowserForm();
browserForm.Show();
browserForm.PrintHtml(doctext, printerName, this);
}
private string magic = "gkhjagdsfgkjhgkjhasdfyehecghgefuuweyuyjhweuyg1233498712vcgdqssedrrggggg";
private string InstructionTextRow(int textId, string title, string caption, bool optional)
{
string res;
NumberedText txt = new NumberedText(textId,Connection);
if (txt.Text=="" && optional) {
res = "";
} else {
res = "<tr><td valign=top>"
+ (title.ToString().Length > 0 ? "<b>" + xmlencode(title.Replace(" ", magic)).Replace(magic, " ") + "</b><br/>" : "")
+ xmlencode(caption) + "</td><td valign=top width=1%>" + (txt.Id > 0 ? "<div width=100% style=\"border: gainsboro 1px solid\">" + txt.Id.ToString() + "</div> " : "") + "</td><td valign=top borderwidth=1 style=\"border: gainsboro 1px solid\" width=80%>" + xmlencode(txt.Text.ToString()).Replace("\n", " <br/>").Replace("\r", "") + " </td></tr>";
}
return res;
}
public string xmlencode(string s)
{
XmlDocument xmldoc = new XmlDocument();
XmlNode xn = xmldoc.CreateElement("data");
xn.InnerText = s;
return xn.InnerXml;
}
private string FrameDivRight(string s)
{
return "<div halign=right style=\"border: lavender 1px solid\">" + xmlencode(s) + "</div>";
}
private string FramedText(string caption, string s)
{
return "<table width=100%><tr><td><i>" + xmlencode(caption.Replace(" ", magic)).Replace(magic, " ") + " </td><td width=100% style=\"border: gray 1px solid\">" + (s.ToString().Length > 0 ? xmlencode(s) : " ") + "</i></td></tr></table>";
}
private string CondFramedText(string caption, string s)
{
return (s.Length > 0) ? FramedText(caption, s) : " ";
}
private string rowtext(AlarmInstruction instruction, int textidx, string title, bool optional) {
int textId = instruction.textids[textidx];
return InstructionTextRow(textId,title,TextTypeName[textidx],optional);
}
private void WriteAlarmInstructions(TextWriter textwriter, string whereclause, string timestamp, string qualification, string prefix, string postfix)
{
//String sql = "select id from alarm.point"+(String.IsNullOrEmpty(whereclause) ? "": " where "+whereclause)+" order by useradr";
String sql = (new AlarmInstruction()).BasicSelect + (String.IsNullOrEmpty(whereclause) ? "" : " where " + whereclause) + " order by useradr";
OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(sql, Connection);
OleDbDataReader reader = cmd.ExecuteReader();
bool first = true;
textwriter.Write(prefix);
while (reader.Read())
{
try
{
AlarmInstruction instruction = new AlarmInstruction();
instruction.InitFromReader(reader);
WriteAlarmInstruction(textwriter, instruction, timestamp, false, qualification, "<div " + (first ? "" : "style=\"page-break-before:always\"") + "></div>", "");
//textwriter.Write("s=" + s + "<br>");
first = false;
}
catch
{
}
}
reader.Close();
textwriter.Write(postfix);
}
private bool WriteAlarmInstruction(TextWriter textwriter, AlarmInstruction instruction, string timestamp, bool alarmTest, string qualification, string prefix, string postfix)
{
/*
textwriter.Write(DateTime.Now.ToString() + " ALARM " + id.ToString() + "<br/>");
return true
*/
if (qualification != "ALARM") timestamp = "";
string pageContents = "";
pageContents += "<style>TD,P,I,INPUT,DIV{font-family:arial,helvetica; font-size:8pt}</style>";
pageContents += "<style>B{font-family:arial,helvetica; font-size:10pt}</style>";
pageContents += "<table cellspacing=3 width=100%><tr><td align=left><h1>"
+(alarmTest ? "Alarmafprøvning" : "Alarminstruks")
+"</h1></td><td align=right>" + xmlencode(instruction.SystemId + " ").Replace(" ", " ") + xmlencode(timestamp) + "</td></tr></table>";
pageContents += "<table width=100%>";
pageContents += "<tr><td>" + FramedText("ID nr.", instruction.UserAdr.ToString()) + "</td><td valign=right>" + FramedText("Betegnelse", instruction.Caption) + "</td><td>" + FramedText("Prioritet ", instruction.Notif) + "</td></tr>";
pageContents += "<tr><td>" + CondFramedText("$ Adr.", instruction.TechAdr.ToString()) + "</td><td valign=right>" + CondFramedText("Alarmgrænse høj", instruction.AlarmLimitHigh.ToString()) + "</td><td>" + CondFramedText("Enhed", instruction.Unit.ToString()) + "</td></tr>";
pageContents += "<tr><td></td><td valign=right>" + CondFramedText("Alarmgrænse lav", instruction.AlarmLimitLow.ToString()) + "</td><td>" + CondFramedText("Tidsforsinkelse", instruction.TimeDelay.ToString()) + "</td></tr>";
pageContents += "<tr><td></td><td valign=right>" + FramedText("Alarm GMP kritisk", instruction.GMPCritical.ToString()) + "</td><td>" + FramedText("Kræver alarmen afvigelse (NDP)", instruction.Deviation.ToString()) + "</td></tr>";
pageContents += "</table>";
pageContents += "<table cellspacing=3>";
pageContents += "<tr height=2px><td colspan=3><hr></td></tr>";
pageContents += "<tr><td>"
+ FramedText("Bruger afd.",instruction.UserDept)
+"</td><td colspan=2>"
+"<table><tr><td>"
+ FramedText("Ansvarlig",instruction.Responsible)
+"</td><td>"
+ FramedText("TDA driftsgruppe",instruction.OperationsGroup)
+"</td></tr></table>"
+"</td></tr>";
pageContents += "<tr><td colspan=3 height=2px><hr></td></tr>";
pageContents += rowtext(instruction, 8, "", false);
pageContents += rowtext(instruction, 6, "", false);
pageContents += "<tr height=2px><td colspan=3><hr></td></tr>";
pageContents += rowtext(instruction, 1, "Portvagt aktion/tilkald", false);
pageContents += rowtext(instruction, 3, "", true);
pageContents += "<tr height=2px><td colspan=3><hr></td></tr>";
pageContents += rowtext(instruction, 7, "Aktion TDA", false);
pageContents += rowtext(instruction, 5, "", false);
pageContents += rowtext(instruction, 9, "", false);
pageContents += rowtext(instruction, 2, "Underret bruger", false);
pageContents += rowtext(instruction, 4, "", true);
pageContents += rowtext(instruction, 10, "", true);
if (instruction.UserUpdate.Length > 0)
{
pageContents += "<tr><td colspan=2></td><td valign=right><i>" + xmlencode("Instruks opdateret "+ instruction.UserUpdate) + "</i></td></tr>";
}
pageContents += "</table>";
textwriter.Write(prefix+"<table height=100% width=100%><tr><td valign=top>" + pageContents + "</td></tr></table>"+postfix);
return true;
}
public String ConnectionString
{
get { return Properties.Settings.Default.ConnectionString; }
}
private OleDbConnection con_;
public OleDbConnection Connection
{
get
{
if (con_ == null)
{
OleDbConnection connection = new OleDbConnection(ConnectionString);
try
{
connection.Open();
}
catch
{
}
con_ = connection;
}
return con_;
}
}
class AlarmInstruction
{
public int Id;
public string SystemId;
public string UserAdr;
public string Caption;
public string UserDept;
public string Responsible;
public string OperationsGroup;
public string Notif;
public string NotifMaster;
public string TechAdr;
public string AlarmLimitHigh;
public string AlarmLimitLow;
public string Unit;
public string TimeDelay;
public string GMPCritical;
public string Deviation;
public string UserUpdate;
public string Recipient;
public int[] textids;
public DateTime NotifDateTime = new DateTime(0);
private string _targetPrinters = null;
public string TargetPrinters
{
get {
try
{
if (_targetPrinters == null)
{
if (NotifDateTime.CompareTo(new DateTime(0))==0)
{
NotifDateTime = DateTime.Now;
}
_targetPrinters = "";
}
string sql = "select targets,weekday,hour from notifdetail where notifmaster=" + NotifMaster+" order by weekday,hour";
OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(sql, Connection);
OleDbDataReader reader = cmd.ExecuteReader();
DateTime now = NotifDateTime;
DayOfWeek wd = now.DayOfWeek;
int weekday = (wd==DayOfWeek.Sunday ? 7 : 1+(wd-DayOfWeek.Monday));
while (reader.Read())
{
int fromweekday = int.Parse(reader["weekday"].ToString());
DateTime fromhour = reader.GetDateTime(reader.GetOrdinal("hour"));
if (fromweekday<weekday || (fromweekday==weekday && (fromhour.TimeOfDay<=now.TimeOfDay) ))
{
_targetPrinters = reader["targets"].ToString();
}
}
reader.Close();
}
catch
{
}
return _targetPrinters;
}
}
private string _smsTarget = null;
public string SmsTarget
{
get {
if (_smsTarget == null)
{
if (TargetPrinters.Contains("S") && Recipient.Length>0) {
try
{
string sql = "select mobile from recipients where id="+ (new MySqlLayer()).SqlLit(Recipient);
OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(sql, Connection);
OleDbDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
_smsTarget = reader["mobile"].ToString();
}
reader.Close();
}
catch
{
}
}
}
if (_smsTarget == null)
{
_smsTarget = "";
}
return _smsTarget.Trim();
}
}
private IniStructure _ini = null;
public IniStructure Ini
{
get {
if (_ini == null)
{
_ini = IniStructure.ReadIni("C:\\alarm\\alarm.ini");
}
return _ini;
}
}
public string PrinterName(int n)
{
string pname = "";
try
{
pname = Ini.GetValue("Printers", "printer" + n.ToString());
}
catch
{
}
if (pname.Length==0) throw new Exception("Printer selection failed. Printer #"+n.ToString()+", name \""+pname+"\"");
return pname;
}
public void InitFromReader(OleDbDataReader reader)
{
Id = int.Parse(reader["id"].ToString());
SystemId = reader["systemid"].ToString();
UserAdr = reader["useradr"].ToString();
Caption = reader["descr"].ToString();
Notif = reader["notifnam"].ToString();
NotifMaster = reader["notifmaster"].ToString();
TechAdr = reader["techadr"].ToString();
Unit = reader["unit"].ToString();
TimeDelay = reader["timedelay"].ToString();
AlarmLimitHigh = reader["alarmlimithigh"].ToString();
AlarmLimitLow = reader["alarmlimitlow"].ToString();
GMPCritical = reader["gmpcritical"].ToString() == "1" ? "Ja" : "Nej";
Deviation = reader["deviation"].ToString() == "1" ? "Ja" : "Nej";
UserUpdate = reader["user_update"].ToString();
UserDept = reader["dept"].ToString();
Responsible = reader["userid"].ToString();
OperationsGroup = reader["operationsgroup"].ToString();
Recipient = reader["recipient"].ToString();
int n = TextTypeName.GetUpperBound(0);
textids = new int[n + 1];
for (int i = 1; i <= n; i++)
{
try
{
textids[i] = int.Parse(reader[TextFieldName[i]].ToString());
}
catch
{
textids[i] = 0;
};
}
}
public String BasicSelect {
get {
return "select *,(select usernam from notifmaster where id= point.notifmaster) notifnam,(select id from alarmsystem) systemid from alarm.point";
}
}
public AlarmInstruction()
: base()
{
}
OleDbConnection Connection = null;
public AlarmInstruction(int id, OleDbConnection connection)
: base()
{
String sql = BasicSelect + " where id=" + id.ToString();
try
{
Connection = connection;
OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(sql, connection);
OleDbDataReader reader = cmd.ExecuteReader();
if (reader.Read())
{
InitFromReader(reader);
}
reader.Close();
}
catch { }
}
}
private void button2_Click(object sender, EventArgs e)
{
SQL_performer performer = new SQL_performer();
performer.Connection = Connection;
performer.Show();
}
}
class NumberedText
{
public NumberedText(int textId, OleDbConnection connection)
: base()
{
String sql = "select txt,typ from alarm.txt where id="+textId.ToString();
OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(sql, connection);
try
{
if (textId > 0)
{
OleDbDataReader reader = cmd.ExecuteReader();
if (reader.Read())
{
int n = 0;
_Id = textId;
_Text = reader[n++].ToString();
_Typ = int.Parse(reader[n++].ToString());
}
reader.Close();
}
}
catch
{
_Error = true;
}
if (_Text == null) _Text = "";
if (_Typ == null) _Typ = 0;
}
private DateTime _TimeStamp;
public DateTime TimeStamp
{
get { return _TimeStamp; }
set { _TimeStamp = value; }
}
private bool _Error;
public bool Error
{
get { return _Error; }
}
private int _Id;
public int Id
{
get { return _Id; }
}
private string _Text;
public string Text
{
get { return _Text; }
}
private int _Typ;
public int Typ
{
get { return _Typ; }
}
}
public class MySqlLayer
{
public virtual String SqlLit(Object obj)
{
if (obj == null)
{
return "null";
}
else if (obj is string)
{
return (String.IsNullOrEmpty(obj as string) ? "null" : ("'" + (obj as string).Replace("'", "''") + "'"));
}
else if (obj is int)
{
return (obj.ToString());
}
else if (obj is DateTime)
{
DateTime d = (DateTime)obj;
return String.Format("TO_DATE('{0:0000}-{1:00}-{2:00} {3:00}:{4:00}','YYYY-MM-DD HH24:MI')", d.Year, d.Month, d.Day, d.Hour, d.Minute);
}
else
{
return "null";
}
}
}
}
我认为你的问题是你应该尽快关闭你的连接 下面是我将如何编写ProcessBatch方法：
private void ProcessBatch()
{
using (OleDbConnection connection = new OleDbConnmection(ConnectionString))
{
connection.Open();
{
String sql = "select recid,action,parm1,parm2,parm3,parm4,targetfile from alarm.batch where recid>0 order by recid";
OleDbCommand cmd = new OleDbCommand(sql, connection);
using (OleDbDataReader reader = cmd.ExecuteReader())
{
if (reader.Read())
{
int n = 0;
string recid_str = reader[n++].ToString();
string action = reader[n++].ToString();
string parm1 = reader[n++].ToString();
string parm2 = reader[n++].ToString();
string parm3 = reader[n++].ToString();
string parm4 = reader[n++].ToString();
string targetfile = reader[n++].ToString();
sql = "update alarm.batch set recid= -" + recid_str + " where recid=" + recid_str;
cmd = new OleDbCommand(sql, connection);
cmd.ExecuteNonQuery();
if (ProcessBatchItem(action, parm1, parm2, parm3, parm4, targetfile))
{
sql = "delete from alarm.batch where recid= -" + recid_str;
cmd = new OleDbCommand(sql, connection);
cmd.ExecuteNonQuery();
}
}
}
}
}
}
您也可以考虑使用OLIDB转换。< /P> 在应用程序中，应删除连接属性
祝你的应用程序好运。不要像这里那样添加空的catch块：尝试{connection.Open；}catch{}。始终在使用完using-statemenet后立即关闭连接。抱歉，所有的细节-但这不是我的代码。我只是在数据库脱机时才尝试找到解决问题的方法。非常感谢。我明天会试试这个。。。