正如我之前提出的问题：How to stay connected to database until screen close?
首先，让我向所有人道歉，我不解释我的情况。
好吧，我的情况是更新到100条记录。我使用For loop创建了一个真实的工作并记录了他们的结果。
private void button1_Click(object sender, EventArgs e)
{
int i;
KeyEventArgs keyEvent = new KeyEventArgs(Keys.Enter); //Create keydown event
Performance perf = new Performance(); //Class for measure time and logging
perf.Start(); //Start stopwatch
for (i = 1; i <= 100; i++)
{
txtLotNo.Text = i.ToString("0000000000") + "$01"; //Generate input ID
txtLotNo_KeyDown(sender, keyEvent); //Fire keydown event
}
perf.Stop(); //Stop stopwatch
perf.Log(frmInvCtrl.appPath,"Stock In (Stay connected)- " + frmInvCtrl.instance); //Logging
}
这是一个Performance Class。
class Performance
{
private Stopwatch _sw = new Stopwatch(); //Create stopwatch property
public double GetWatch
{
get
{
return this._sw.ElapsedMilliseconds;
}
}
public void Start()
{
Stop();
_sw.Reset();
_sw.Start();
}
public void Stop()
{
if (_sw.IsRunning)
{
_sw.Stop();
}
}
public void Log(string path,string menu)
{
string logName = path + "\\Log_" + System.DateTime.Now.ToString("yyyyMMdd") + ".txt";
string logDetail = System.DateTime.Now.ToString("yyyy/MM/dd hh:mm:ss") + " - [" + menu + "] "
+ "Process 100 record in [" + (((double)_sw.ElapsedMilliseconds / 1000)).ToString() + "] seconds";
using(StreamWriter writer = new StreamWriter(logName,true))
{
writer.WriteLine(logDetail); //wirtelog
}
}
}
这些是日志结果
2017/02/19 08:16:05 - [Stock In - On Cloud] Process 100 record in [68.352] seconds
2017/02/19 08:17:34 - [Stock In - On Cloud] Process 100 record in [70.184] seconds
2017/02/19 08:20:28 - [Stock In - On Cloud] Process 100 record in [56.66] seconds
2017/02/19 08:21:34 - [Stock In - On Cloud] Process 100 record in [60.605] seconds
2017/02/19 08:22:44 - [Stock In - On Cloud] Process 100 record in [68.27] seconds
2017/02/19 08:24:43 - [Stock In - Network Server] Process 100 record in [46.86] seconds
2017/02/19 08:26:05 - [Stock In - Network Server] Process 100 record in [31.746] seconds
2017/02/19 08:26:48 - [Stock In - Network Server] Process 100 record in [31.859] seconds
2017/02/19 08:27:32 - [Stock In - Network Server] Process 100 record in [31.003] seconds
2017/02/19 08:28:17 - [Stock In - Network Server] Process 100 record in [40.487] seconds
2017/02/19 08:32:42 - [Stock In (Stay connected)- On Cloud] Process 100 record in [18.196] seconds
2017/02/19 08:35:47 - [Stock In (Stay connected)- On Cloud] Process 100 record in [14.721] seconds
2017/02/19 08:36:30 - [Stock In (Stay connected)- On Cloud] Process 100 record in [15.903] seconds
2017/02/19 08:37:31 - [Stock In (Stay connected)- On Cloud] Process 100 record in [15.811] seconds
2017/02/19 08:38:15 - [Stock In (Stay connected)- On Cloud] Process 100 record in [16.4] seconds
2017/02/19 08:43:08 - [Stock In (Stay connected)- Network Server] Process 100 record in [13.09] seconds
2017/02/19 08:43:25 - [Stock In (Stay connected)- Network Server] Process 100 record in [13.03] seconds
2017/02/19 08:43:40 - [Stock In (Stay connected)- Network Server] Process 100 record in [13.051] seconds
2017/02/19 08:43:55 - [Stock In (Stay connected)- Network Server] Process 100 record in [12.992] seconds
2017/02/19 08:44:12 - [Stock In (Stay connected)- Network Server] Process 100 record in [14.953] seconds
我练习了连接池。但是，这些结果显示，在许多记录情况下，保持连接到数据库的速度更快。
有没有适合这种情况的做法？
编辑：2017/02/21
打开表单代码时，这是打开的连接：
private void frm_Load(object sender, EventArgs e) //Open menu
{
... //statement
frmMain.sqlConn1 = new SqlConnection();
frmMain.sqlConn1.ConnectionString = frmMain.connectionString1;
frmMain.sqlConn1.Open();
... //statement
}
更新代码：
public static long ScanUpdate(string lotNo)
{
string scanLotNo = "";
int scanIndex = 0;
if (!SplitBarcode(lotNo, ref scanLotNo, ref scanIndex))
{
//Invalid Barcode data
return -919;
}
//Prepare sql command
string updStatus = (frmMain.shelfScan) ? "05" : "10";
string sql = <sql statement>
try
{
using (SqlCommand sqlCmd = new SqlCommand(sql, frmMain.sqlConn1)) //frmMain.sqlConn1 is connection in form_Load()
{
if (sqlCmd.ExecuteNonQuery() <= 0)
{
//No row affect
//frmMain.sndPlay.Play();
return -99;
}
else
{
//Completed
return 0;
}
}
}
catch
{
return 99;
}
finally
{
}
}
退出时配置连接
private void btnBack_Click(object sender, EventArgs e)
{
frmMain.sqlConn1.Dispose();
this.Close();
}
答案 0 :(得分：6)
从单个线程的响应性的角度来看，保持连接打开会更快。连接池的目的是通过在线程之间共享来减少打开新连接的开销，同时不会在共享SQL Server上消耗过多的连接。
每次将连接释放到连接池然后重新使用时，协议栈都会调用sp_resetconnection来清理服务器上的状态。您可以通过针对SQL Server运行探查器跟踪来查看此内容。
由于每个进程都为每个连接字符串都有自己的连接池，因此只有在进程内存在争用时才会从连接池中受益。
答案 1 :(得分：2)
每个人都缺少的部分是它的 Windows CE ，它在紧凑版上的不常见的打开连接可能非常慢。
然而，那说，那些时候看起来有点夸张。请参阅此QA以获取解决方法： How can I make my SQL Server CE connection open faster?答案 2 :(得分：0)
在许多方面，您可能会遇到上述代码的问题。
SqlConnection实例。 SqlConnection类将自动汇集封面下的连接。当您调用close()函数时，连接只会返回池中。您可以使用连接字符串中的属性控制池行为。通过为所有函数保留相同的连接对象，您将强制它们被序列化。
这是reference to some connection string properties。看看Connection Lifetime。
我会从SqlConnection函数中删除form_load()实例并按如下方式编写ScanUpdate：
public static long ScanUpdate(string lotNo)
{
string scanLotNo = "";
int scanIndex = 0;
if (!SplitBarcode(lotNo, ref scanLotNo, ref scanIndex))
{
//Invalid Barcode data
return -919;
}
//Prepare sql command
string updStatus = (frmMain.shelfScan) ? "05" : "10";
string sql = <sql statement>
try
{
using (SqlConnection conn = new SqlConection(frmMain.connectionString1)) {
SqlCommand sqlCmd = new SqlCommand(sql, conn);
if (sqlCmd.ExecuteNonQuery() <= 0)
{
//No row affect
//frmMain.sndPlay.Play();
return -99;
}
else
{
//Completed
return 0;
}
conn.Close();
}
}
catch
{
return 99;
}
}
对于*_Click事件处理函数，请务必检查以确定是否需要重新调用该事件：
private void button1_Click(object sender, EventArgs e)
{
if (this.InvokeRequired)
{
this.Invoke(new EventArgsDelegate(button1_Click), new object[] { sender, ea });
}
// Do some stuff
}
有关事件处理的详细信息，请参阅this answer。