不允许改变的ConnectionString

-1

conn6.ConnectionString = "server=" + global_variables.web_server_ip + "; user id=" + global_variables.web_server_username + "; password=" + global_variables.web_server_password + "; database=" + global_variables.web_server_database + "; " 
conn6.Open() 

SQL = "select calltype from billing group by calltype " 
myCommand6.Connection = conn6 
myCommand6.CommandText = SQL 

reader6 = myCommand6.ExecuteReader 

While reader6.Read 
    cdr_call_type = reader6.GetString(0) 
        '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
    'do VoIP bit 
        '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
    If customerid_voip <> "" Or customerid_voip_new <> "" Then 
     'do customer VoIP Bit, which means getting the latest value from billing table 
     TextBox1.Text = "Got VoIP - " + cdr_call_type + vbCrLf + TextBox1.Text 
     Me.Refresh() 

     conn3.ConnectionString = "server=" + global_variables.web_server_ip + "; user id=" + global_variables.web_server_username + "; password=" + global_variables.web_server_password + "; database=" + global_variables.web_server_database + "; " 
     conn3.Open() 

     SQL = "select reseller_bill, customer_bill, phone, calltype, timestamp, seconds from billing where calltype = '" + reader6.GetString(0) + "' AND (source='CDR' or source='' or source='VOIP') and (company='" + customerid_voip + "' or company='" + customerid_voip_new + "') " 
     myCommand3.Connection = conn3 
     myCommand3.CommandText = SQL 

     reader3 = myCommand3.ExecuteReader 

     While reader3.Read 
      'do stuff here 
     End While 

     reader3.Close() 
     conn3.Close() 
    End If 
End While 

reader6.Close() 
conn6.Close()

当我运行代码，我得到的线conn3.Open()一个错误说：

不允许更改'ConnectionString'属性，而连接（state = Open）。

它可以在第一个循环，但是当我避开第二循环停止并显示此错误

来源

2014-10-28 user3843997

错误消息指出在打开连接字符串时无法更改连接字符串。所以你只需要在修改它之前关闭它。 – 2014-10-28 09:22:57

我已经关闭它，使用conn3.close（） – user3843997 2014-10-28 09:23:46

关闭conn6在尝试使用另一个连接之前 – NoviceProgrammer 2014-10-28 09:24:46

问题出在这里while loop你试图改变一个已经定义的连接的连接字符串，它可以通过每次在循环内创建一个新连接来避免，如下所示：

While reader6.Read 
    cdr_call_type = reader6.GetString(0) 
    If customerid_voip <> "" Or customerid_voip_new <> "" Then 
     TextBox1.Text = "Got VoIP - " + cdr_call_type + vbCrLf + TextBox1.Text 
     Me.Refresh() 
     Dim conn3 As New OdbcConnection '<--- declaring a new connection 
     '<---- in each iteration connection is treated as a new one 
     '<---- so initializing is not became a problem 
     conn3.ConnectionString = "server=" + global_variables.web_server_ip + "; user id=" + global_variables.web_server_username + "; password=" + global_variables.web_server_password + "; database=" + global_variables.web_server_database + "; " 
     conn3.Open() 
     '<------ 
     ' Remaining codes comes here 
     '<------ 
    End IF

来源

2014-10-28 09:47:09

您可以添加一些额外的检查，修改前：

If conn3.State = ConnectionState.Open Then 
    conn3.Close() 
End If

来源

2014-10-28 09:30:32 Baby

不允许改变的ConnectionString

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