共享数据库变量的正确方法(asp.net)
我一直在使用以下代码共享数据库变量:共享数据库变量的正确方法(asp.net),asp.net,database,declaration,fxcop,code-sharing,Asp.net,Database,Declaration,Fxcop,Code Sharing,我一直在使用以下代码共享数据库变量: Namespace DataAccessVariables Public Class Vars Public Shared s As String Public Shared con As String = WebConfigurationManager.ConnectionStrings("Dev").ToString() Public Shared c As New SqlConnection(co
Namespace DataAccessVariables
Public Class Vars
Public Shared s As String
Public Shared con As String = WebConfigurationManager.ConnectionStrings("Dev").ToString()
Public Shared c As New SqlConnection(con)
Public Shared x As New SqlCommand(s, c)
End Class
End Namespace
然后,我将其导入到我的项目中,如下所示:
Imports DataAccessVariables.Vars
当我使用FXCop查看站点时,我收到以下消息:
Error, Certainty 90, for StaticHolderTypesShouldNotHaveConstructors
{
Target : DBVars (IntrospectionTargetType)
Resolution : "Remove the public constructors from 'Vars'."
Help : http://msdn2.microsoft.com/library/ms182169(VS.90).aspx (String)
Category : Microsoft.Design (String)
CheckId : CA1053 (String)
RuleFile : Design Rules (String)
Info : "Instances of types that define only static members
do not need to be created. Many compilers will automatically
add a public default constructor if no constructor
is specified. To prevent this, adding an empty private
constructor may be required."
Created : 2010/04/20 01:25:16 PM (DateTime)
LastSeen : 2010/04/21 07:17:46 AM (DateTime)
Status : Active (MessageStatus)
Fix Category : Breaking (FixCategories)
}
如果我从声明中删除“Public Shared”,那么这些变量就不会出现在我的页面中。有人能告诉我分享它们的正确方法吗
非常感谢,
菲尔。此错误并没有告诉您删除公共共享变量。相反,它让您知道可以创建
Vars
类的新实例,即使它只包含共享的成员。要解决此问题,请定义专用构造函数:
Private Sub New()
End Sub
这将防止任何代码在类本身之外创建Vars
类的实例。这是类中唯一的代码吗
此外,不应创建全局(静态)SqlConnection
。只需按需创建SqlConnection
和SqlCommand
对象。连接池将确保一次只进行一个物理数据库连接
按照这里的方式,它不是线程安全的(例如,如果两个人同时提出请求,事情会变得非常糟糕)