在vb中从存储的proc获取输出参数到BL函数

Question

我不是很精通来自 c# 背景的 vb.net。我有一个带有 btn 和输入的表单，它接受一个字符串并通过存储的过程在数据库中运行和更新。存储过程应该返回一个@Message 和@Success 参数。但是，我有点困惑如何取回这些参数。我有 3 个功能。 btn click sub（调用BL函数）、BL函数（调用DA函数）、DA函数（调用sql server中存储的proc）。我也对整个 byref 的工作方式感到困惑。我读到我不必从我的 DA 函数返回任何内容，但如果这是真的，那么 BA 函数将如何接收成功/消息参数？

我知道我在这里错过了很多。有人可以帮我重新构建它，并简要解释它是如何/为什么这样工作的。下面是我的代码。

BTN 点击子：

    'Button click that calls CertificateOrder BL function InvalidateCertificate() 
    Private Sub btnInvalidateCertificate_Click(sender As Object, e As System.EventArgs) Handles btnInvalidateCertificate.Click
        'Cert ID to invalidate
        Dim certificateId As String = txtCertificateId.Value
        Dim msg As Response.BaseResponse

        'Call stored proc from BL

        msg = CertificateOrder.InvalidateCertificate(certificateId)
        Me.txtCertificateId.ErrorText = msg.Message

        If msg.Success Then
            Forms.FadeForm.ShowDialog(msg.Message, "Success", Forms.FadeForm.MessageIcons.Information, Forms.FadeForm.MessageButtons.Ok)
        End If
    End Sub

BL功能：

   ''' <summary>
    ''' Calls DataAccess function InvalidateCertificate()
    ''' to invalidate certificate
    ''' </summary>
    Public Shared Function InvalidateCertificate(ByVal certificateId As System.String) As Response.BaseResponse

        Using context As New CORADBContext

            Dim message As System.String = ""
            Dim success As System.Boolean = False

            context.InvalidateCertificate(certificateId, success, message)

            Return message
        End Using
    End Function

DA功能：

   ''' <summary>
    ''' Calls the [spInvalidateCertificate] stored proc
    ''' to update a cert to be invalid
    ''' </summary>
    ''' <returns></returns>
    <Extension>
    Public Function InvalidateCertificate(ByVal context As DbContextBase,
                                          ByVal certificateId As System.String,
                                          ByRef success As System.Boolean,
                                          ByRef message As System.String) As Int32

        Dim successParameter As New SqlParameter("@Success", success) With {.Direction = ParameterDirection.InputOutput, .Value = False}
        Dim messageParameter As New SqlParameter("@Message", message) With {.Direction = ParameterDirection.InputOutput, .Value = ""}

        Dim parameters() As SqlParameter = {New SqlParameter("@CertificationValue", certificateId), successParameter, messageParameter}

        Dim results As Int32 = context.ExecuteProcedure("Orders.spInvalidateCertificate", parameters)

        success = DirectCast(successParameter.Value, System.Boolean)
        message = DirectCast(messageParameter.Value, System.String)
        'success and message need to be returned

        Return 0
    End Function

Answer 1

您可以使流程更清洁。如 cmets 中所述，我不确定 Response.BaseResponse 对象是什么，因此假设您没有数据结构（即类）来返回响应数据。您可以像这样创建一个：

Public Class MyResponse

    Public ReadOnly Property Success As Boolean = False
    Public ReadOnly Property Message As String = String.Empty

    Public Sub New(success As Boolean, message As String)
        Me.Success = success
        Me.Message = message
    End Sub

End Class

现在，重构代码，使 DA 函数返回 MyResponse 类型的对象：

Public Function InvalidateCertificate(context As DbContextBase,
                                      certificateId As String) As MyResponse

    Dim successParameter As New SqlParameter("@Success", success) With {.Direction = ParameterDirection.InputOutput, .Value = False}
    Dim messageParameter As New SqlParameter("@Message", message) With {.Direction = ParameterDirection.InputOutput, .Value = String.Empty}

    Dim parameters() As SqlParameter = {New SqlParameter("@CertificationValue", certificateId), successParameter, messageParameter}

    Dim results As Integer = context.ExecuteProcedure("Orders.spInvalidateCertificate", parameters)

    Return New MyResponse(successParameter.Value, messageParameter.Value)

End Function

现在，重构 BL 函数，使其也返回一个 MyResponse 对象：

Public Shared Function InvalidateCertificate(ByVal certificateId As System.String) As MyResponse

    Using context As New CORADBContext

        ' Where does context get passed to the DA???
        Return context.InvalidateCertificate(certificateId)

    End Using

End Function

我不理解的一件事是调用contact.InvalidateCertificate() 的原始代码没有传入context 的变量？？？

最后，重构您的 UI 以处理来自对 CertificateOrder.InvalidateCertificate(certificateId) 的调用的 MyResponse 结果