Mysql 个连接未与 VB.NET 个应用程序关闭
Mysql connections not closing with VB.NET application
这是我第一次来这里，我要疯了，因为我有这个问题：
我正在开发一个 windows 表单应用程序 VB.NET 使用多种类型的连接（mysql，odbc 和 SQL 服务器）一切正常，直到我得到进入 MySQL..
MySQL 服务器是物理 windows 7 台电脑，我通过 IPSEC VPN 隧道连接到它。
我需要每 x 秒执行 2 个 MySQL 连接，如果我在第一次连接后得到某种类型的结果，那么我将打开第二个，依此类推每 x 秒（这都是写的在我的 timer.tick 事件处理程序中）。
问题是 MySQL 服务器上的某些连接经常在 MySQL 服务器上保持活动状态（已建立），我无法找出原因......代码看起来不错，有打开和关闭方法在正确的时间声明，我也尝试过 Dispose、ClearPool 和 ClearAllPools 方法，但我一直保持这些连接，直到我关闭我的程序或它达到连接限制。
代码如下：
Class 连接：
Public Sub connMySQL()
Dim connstring As String
Try
If stabilimento = "1PR" Then
If cesoia = "" Then
connstring = "server=192.168.123.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Else
connstring = "server=192.168.123.253;userid=xx;password=xx;database=xx;Connect Timeout=30"
End If
End If
If stabilimento = "2PR" Then
If cesoia = "" Then
connstring = "server=192.168.1.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Else
connstring = "server=192.168.123.253;userid=root;password=xx;database=xx;Connect Timeout=30"
End If
End If
conMySql = New MySqlConnection(connstring)
If conMySql.State = ConnectionState.Closed Then
conMySql.Open()
End If
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
Class执行迭代的地方：
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
connMySQL()
comm = New MySqlCommand("SELECT count_1,count_2,start_stop,data_ora,id FROM plc_contatori where plc_nome='" + plc_nome + "' and data_ora > '" + data_ieri.ToString("yyyy/MM/dd") + "' order by data_ora desc limit 1", conMySql)
dr = comm.ExecuteReader()
While (dr.Read())
count_1(0) = dr.GetValue(0)
start_stop(0) = dr.GetValue(2)
data_ora(0) = dr.GetValue(3)
If id <> dr.GetValue(4) And count_2(0) <> dr.GetValue(1) Then
id = dr.GetValue(4)
count_2(0) = dr.GetValue(1)
Else
Exit Sub
End If
End While
dr.Close()
dr.Dispose()
conMySql.Close()
conMySql.Dispose()
conMySql.ClearPool(conMySql)
conMySql.ClearAllPools()
If Not conMySql Is Nothing Then conMySql = Nothing
comm.Dispose()
If start_stop(0) = 1 Then
Exit Sub
End If
Dim dum_count_2 As Integer = count_2(0) - 1
connMySQL()
comm = New MySqlCommand("select count_1,count_2,start_stop,data_ora from plc_contatori where plc_nome='" + plc_nome + "' and data_ora > '" + data_ieri.ToString("yyyy/MM/dd") + "' AND count_2=" + dum_count_2.ToString + " ORDER BY data_ora desc limit 1", conMySql)
dr = comm.ExecuteReader()
While (dr.Read())
count_1(1) = dr.GetValue(0)
count_2(1) = dr.GetValue(1)
start_stop(1) = dr.GetValue(2)
data_ora(1) = dr.GetValue(3)
End While
dr.Close()
dr.Dispose()
conMySql.Close()
conMySql.Dispose()
conMySql.ClearPool(conMySql)
conMySql.ClearAllPools()
If Not conMySql Is Nothing Then conMySql = Nothing
comm.Dispose()
If count_1(0) = count_1(1) And start_stop(1) <> 1 And count_2(0) <> count_2(1) Then
'sub that reads some values from an odbc connection
CheckFermo()
End If
End Sub
注意，我没有在这部分代码中声明的变量在 public class 形式中声明。
我想知道可能出了什么问题...也许在第一个连接被服务器关闭之前建立了第二个连接？
我将 connMySQL 方法更改为 returns 连接字符串的函数。我已经声明了几个变量，所以代码很有意义。我对数据类型做了几个假设。如果这些值实际存储为字符串，您可能必须将其改回 String 和 VarChar。 （我希望他们不是）
您可以使用单个连接，但所有赋值和比较都将在打开的连接下进行。
Private stabilimento As String
Private cesoia As String
Public Function connMySQL() As String
Dim connstring As String
Select Case True
Case stabilimento = "1PR" And cesoia = ""
connstring = "server=192.168.123.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Case stabilimento = "2PR" And cesoia = ""
connstring = "server=192.168.1.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Case Else
connstring = "server=192.168.123.253;userid=root;password=xx;database=xx;Connect Timeout=30"
End Select
Return connstring
End Function
Private count_1(10) As Integer
Private count_2(10) As Integer
Private start_stop(10) As Integer
Private data_ora(10) As Date
Private id As Integer
Private plc_nome As String
Private data_ieri As Date
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Using dt As New DataTable
Using cn As New MySqlConnection(connMySQL),
comm = New MySqlCommand("SELECT count_1,count_2,start_stop,data_ora,id
FROM plc_contatori
where plc_nome= @plcNome and data_ora > @dataOra
order by data_ora desc
limit 1", cn)
comm.Parameters.Add("plcNome", MySqlDbType.VarChar).Value = plc_nome
comm.Parameters.Add("dataOra", MySqlDbType.Date).Value = data_ieri '.ToString("yyyy/MM/dd")
cn.Open()
Using dr = comm.ExecuteReader
dt.Load(dr)
End Using 'closes and disposes reader
End Using 'closes and dispose connection and command
count_1(0) = CInt(dt(0)(0))
start_stop(0) = CInt(dt(0)(2))
data_ora(0) = CDate(dt(0)(3))
If id <> CInt(dt(0)(4)) AndAlso count_2(0) <> CInt(dt(0)(1)) Then
id = CInt(dt(0)(4))
count_2(0) = CInt(dt(0)(1))
Else
Exit Sub
End If
End Using 'disposes DataTable
If start_stop(0) = 1 Then
Exit Sub
End If
Dim dum_count_2 As Integer = count_2(0) - 1
Using dt As New DataTable
Using cn As New MySqlConnection(connMySQL),
comm As New MySqlCommand("select count_1,count_2,start_stop,data_ora
from plc_contatori
where plc_nome= @plcNome
and data_ora > @dataOra
AND count_2= @count2
ORDER BY data_ora desc
limit 1", cn)
comm.Parameters.Add("@plcNome", MySqlDbType.VarChar).Value = plc_nome
comm.Parameters.Add("@dataOra", MySqlDbType.Date).Value = data_ieri '.ToString("yyyy/MM/dd")
comm.Parameters.Add("@count2", MySqlDbType.Int32).Value = dum_count_2 '.ToString
cn.Open()
Using dr = comm.ExecuteReader()
dt.Load(dr)
End Using
End Using
count_1(1) = CInt(dt(0)(0))
count_2(1) = CInt(dt(0)(1))
start_stop(1) = CInt(dt(0)(2))
data_ora(1) = CDate(dt(0)(3))
End Using
If count_1(0) = count_1(1) AndAlso start_stop(1) <> 1 AndAlso count_2(0) <> count_2(1) Then
'sub that reads some values from an odbc connection
CheckFermo()
End If
End Sub
这是我第一次来这里，我要疯了，因为我有这个问题：
我正在开发一个 windows 表单应用程序 VB.NET 使用多种类型的连接（mysql，odbc 和 SQL 服务器）一切正常，直到我得到进入 MySQL.. MySQL 服务器是物理 windows 7 台电脑，我通过 IPSEC VPN 隧道连接到它。
我需要每 x 秒执行 2 个 MySQL 连接，如果我在第一次连接后得到某种类型的结果，那么我将打开第二个，依此类推每 x 秒（这都是写的在我的 timer.tick 事件处理程序中）。 问题是 MySQL 服务器上的某些连接经常在 MySQL 服务器上保持活动状态（已建立），我无法找出原因......代码看起来不错，有打开和关闭方法在正确的时间声明，我也尝试过 Dispose、ClearPool 和 ClearAllPools 方法，但我一直保持这些连接，直到我关闭我的程序或它达到连接限制。
代码如下：
Class 连接：
Public Sub connMySQL()
Dim connstring As String
Try
If stabilimento = "1PR" Then
If cesoia = "" Then
connstring = "server=192.168.123.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Else
connstring = "server=192.168.123.253;userid=xx;password=xx;database=xx;Connect Timeout=30"
End If
End If
If stabilimento = "2PR" Then
If cesoia = "" Then
connstring = "server=192.168.1.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Else
connstring = "server=192.168.123.253;userid=root;password=xx;database=xx;Connect Timeout=30"
End If
End If
conMySql = New MySqlConnection(connstring)
If conMySql.State = ConnectionState.Closed Then
conMySql.Open()
End If
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
Class执行迭代的地方：
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
connMySQL()
comm = New MySqlCommand("SELECT count_1,count_2,start_stop,data_ora,id FROM plc_contatori where plc_nome='" + plc_nome + "' and data_ora > '" + data_ieri.ToString("yyyy/MM/dd") + "' order by data_ora desc limit 1", conMySql)
dr = comm.ExecuteReader()
While (dr.Read())
count_1(0) = dr.GetValue(0)
start_stop(0) = dr.GetValue(2)
data_ora(0) = dr.GetValue(3)
If id <> dr.GetValue(4) And count_2(0) <> dr.GetValue(1) Then
id = dr.GetValue(4)
count_2(0) = dr.GetValue(1)
Else
Exit Sub
End If
End While
dr.Close()
dr.Dispose()
conMySql.Close()
conMySql.Dispose()
conMySql.ClearPool(conMySql)
conMySql.ClearAllPools()
If Not conMySql Is Nothing Then conMySql = Nothing
comm.Dispose()
If start_stop(0) = 1 Then
Exit Sub
End If
Dim dum_count_2 As Integer = count_2(0) - 1
connMySQL()
comm = New MySqlCommand("select count_1,count_2,start_stop,data_ora from plc_contatori where plc_nome='" + plc_nome + "' and data_ora > '" + data_ieri.ToString("yyyy/MM/dd") + "' AND count_2=" + dum_count_2.ToString + " ORDER BY data_ora desc limit 1", conMySql)
dr = comm.ExecuteReader()
While (dr.Read())
count_1(1) = dr.GetValue(0)
count_2(1) = dr.GetValue(1)
start_stop(1) = dr.GetValue(2)
data_ora(1) = dr.GetValue(3)
End While
dr.Close()
dr.Dispose()
conMySql.Close()
conMySql.Dispose()
conMySql.ClearPool(conMySql)
conMySql.ClearAllPools()
If Not conMySql Is Nothing Then conMySql = Nothing
comm.Dispose()
If count_1(0) = count_1(1) And start_stop(1) <> 1 And count_2(0) <> count_2(1) Then
'sub that reads some values from an odbc connection
CheckFermo()
End If
End Sub
注意，我没有在这部分代码中声明的变量在 public class 形式中声明。
我想知道可能出了什么问题...也许在第一个连接被服务器关闭之前建立了第二个连接？
我将 connMySQL 方法更改为 returns 连接字符串的函数。我已经声明了几个变量，所以代码很有意义。我对数据类型做了几个假设。如果这些值实际存储为字符串，您可能必须将其改回 String 和 VarChar。 （我希望他们不是）
您可以使用单个连接，但所有赋值和比较都将在打开的连接下进行。
Private stabilimento As String
Private cesoia As String
Public Function connMySQL() As String
Dim connstring As String
Select Case True
Case stabilimento = "1PR" And cesoia = ""
connstring = "server=192.168.123.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Case stabilimento = "2PR" And cesoia = ""
connstring = "server=192.168.1.18;userid=xx;password=xx;database=xx;Connect Timeout=30"
Case Else
connstring = "server=192.168.123.253;userid=root;password=xx;database=xx;Connect Timeout=30"
End Select
Return connstring
End Function
Private count_1(10) As Integer
Private count_2(10) As Integer
Private start_stop(10) As Integer
Private data_ora(10) As Date
Private id As Integer
Private plc_nome As String
Private data_ieri As Date
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Using dt As New DataTable
Using cn As New MySqlConnection(connMySQL),
comm = New MySqlCommand("SELECT count_1,count_2,start_stop,data_ora,id
FROM plc_contatori
where plc_nome= @plcNome and data_ora > @dataOra
order by data_ora desc
limit 1", cn)
comm.Parameters.Add("plcNome", MySqlDbType.VarChar).Value = plc_nome
comm.Parameters.Add("dataOra", MySqlDbType.Date).Value = data_ieri '.ToString("yyyy/MM/dd")
cn.Open()
Using dr = comm.ExecuteReader
dt.Load(dr)
End Using 'closes and disposes reader
End Using 'closes and dispose connection and command
count_1(0) = CInt(dt(0)(0))
start_stop(0) = CInt(dt(0)(2))
data_ora(0) = CDate(dt(0)(3))
If id <> CInt(dt(0)(4)) AndAlso count_2(0) <> CInt(dt(0)(1)) Then
id = CInt(dt(0)(4))
count_2(0) = CInt(dt(0)(1))
Else
Exit Sub
End If
End Using 'disposes DataTable
If start_stop(0) = 1 Then
Exit Sub
End If
Dim dum_count_2 As Integer = count_2(0) - 1
Using dt As New DataTable
Using cn As New MySqlConnection(connMySQL),
comm As New MySqlCommand("select count_1,count_2,start_stop,data_ora
from plc_contatori
where plc_nome= @plcNome
and data_ora > @dataOra
AND count_2= @count2
ORDER BY data_ora desc
limit 1", cn)
comm.Parameters.Add("@plcNome", MySqlDbType.VarChar).Value = plc_nome
comm.Parameters.Add("@dataOra", MySqlDbType.Date).Value = data_ieri '.ToString("yyyy/MM/dd")
comm.Parameters.Add("@count2", MySqlDbType.Int32).Value = dum_count_2 '.ToString
cn.Open()
Using dr = comm.ExecuteReader()
dt.Load(dr)
End Using
End Using
count_1(1) = CInt(dt(0)(0))
count_2(1) = CInt(dt(0)(1))
start_stop(1) = CInt(dt(0)(2))
data_ora(1) = CDate(dt(0)(3))
End Using
If count_1(0) = count_1(1) AndAlso start_stop(1) <> 1 AndAlso count_2(0) <> count_2(1) Then
'sub that reads some values from an odbc connection
CheckFermo()
End If
End Sub