Module SQL_連線狀態模組1
#Region "——连接测试：避免等待时间过长——"
    Dim bConnect As Boolean
    Dim BgWorker1 As New System.ComponentModel.BackgroundWorker
    Dim ServerIP As String
    ''' <summary>
    ''' 测试连接：True-连接成功，False-连接失败
    ''' 参数[必选]：服务器IP
    ''' 参数[可选]：等待超时时间（秒）,默认为1.2秒
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function ConnectTest1(ByVal varServerIP As String, Optional ByVal varTimeout As Decimal = 1.5) As Boolean
        AddHandler BgWorker1.DoWork, AddressOf BgWorker1_DoWork
        Dim g As Integer
        Dim k As Integer
        If BgWorker1.CancellationPending Then
            BgWorker1.CancelAsync()
            '取消BackgroundWorker執行中的工作
        End If
        Try
            If varServerIP = "" Then
                Exit Function
            End If
            ServerIP = varServerIP
            If varTimeout <= 0 Then
                varTimeout = 1.5
            End If
            k = Int(varTimeout * 10)
            bConnect = False
            BgWorker1.WorkerSupportsCancellation = True
            BgWorker1.RunWorkerAsync()
            For g = 1 To k '1.2s
                Threading.Thread.Sleep(100)
                If bConnect = True Then
                    ConnectTest1 = True
                    Exit Function
                End If
            Next
            ConnectTest1 = False
            BgWorker1.CancelAsync()
        Catch ex As Exception
            MsgBox(ex.Message, 1)
        End Try
    End Function
    '--异步动作
    Private Sub BgWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs)
        Call ConnectMSSQLServer()
    End Sub
    '--连接数据库
    Private Function ConnectMSSQLServer() As Boolean
        Dim sqlConTest As Data.SqlClient.SqlConnection ' 连接   
        sqlConTest = New Data.SqlClient.SqlConnection
        sqlConTest.ConnectionString = "Data Source=" + ServerIP + ";Initial Catalog=rt2021;Persist Security Info=True;User ID=b70340;Password=Lee0911274990;Max pool size = 200;Connection Timeout=0"
        Try
            sqlConTest.Open()
            sqlConTest.Close()
        Catch ex As Exception
        Finally
            bConnect = True
        End Try
    End Function
#End Region
End Module