Question

我使用vb.net 2010和sql server management express 2008.我很困惑连接sql和vb.net的代码有什么问题

Imports System.Data.SqlClient

Module Module1
  Public Class connection
    Public Function GetConnect()
      Dim conn As SqlConnection = Nothing
      Dim connString As String = "Data Source=.\SQLEXPRESS; Initial  Catalog=dbMedical;Integrated Security=true"
      conn = New SqlConnection(connString)
      conn.Open()
      If conn.State <> ConnectionState.Open Then
        Return False
      Else
        Return True
      End If
    End Function
  End Class
End Module

但是它不起作用，会出现错误消息。

Answer 1

你有一个内部类的模块，这是你真正想要的吗？除此之外，您无法在方法上下文之外打开连接等，这就是您在connection - 类中所做的。创建一个返回连接的方法。

例如：

Public NotInheritable Class DatabaseFactory

    Private Sub New()
    End Sub

    Public Shared Function GetConnection(openNow as Boolean) As SqlConnection
            Const connString = "Data Source=.\SQLEXPRESS; Initial Catalog=dbMedical;Integrated Security=true"
            Dim conn As SqlConnection = New SqlConnection(connString)
            If openNow Then conn.Open()
            Return conn 
    End Function
End Class

Answer 2

 Imports System.Data
 Imports System.Data.SqlClient      
 Module Connect  
 Public con As SqlConnection     
    Public Function GetConnect()
    con = New SqlConnection("Data Source='(LOCAL)';Initial Catalog='School';Database='School';User ID='sa';Password='';")
    Return con
    End Function
  End Module

在表单激活事件之后：

con=GetConnect()
con.open()
-----
-----
con.close()

连接到SQL Server无法正常工作

2 个答案: