Question

此功能位于App_Code文件夹

中的类文件中

 Public Shared Function CRUD(ByVal _sql As String, ByVal _parameterNames() As String, ByVal _parameterVals() As String) As Integer
        Dim _noOfRowsAffected As Integer
        Dim _connection As SqlConnection = Global.Connection.GetDbConnection()
        Dim _command As New SqlCommand(_sql, _connection)

        Try
            If _parameterNames IsNot Nothing Then
                For i = 0 To _parameterNames.Length - 1
                    _command.Parameters.AddWithValue(_parameterNames(i), _parameterVals(i))
                Next
            End If

            _noOfRowsAffected = _command.ExecuteNonQuery()
        Catch ex As Exception
            'MsgBox(ex.Message)
            _noOfRowsAffected = -1
        Finally
            If _connection.State = ConnectionState.Open Then
                _connection.Close()
                _connection.Dispose()
                _command.Dispose()
            End If
        End Try

        Return _noOfRowsAffected
    End Function

此代码位于aspx.vb页面

Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSave.Click
        Dim _parameterNames(6), _parameterVals(6) As String
        _parameterNames(0) = "@Name"
        _parameterVals(0) = txtCoachingName.Text
        _parameterNames(1) = "@Address"
        _parameterVals(1) = txtCoachingAddress.Text
        _parameterNames(2) = "@Mob1"
        _parameterVals(2) = txtCoachingMob1.Text
        _parameterNames(3) = "@Mob2"
        _parameterVals(3) = txtCoachingMob2.Text
        _parameterNames(4) = "@LLine"
        _parameterVals(4) = txtCoachingLLine.Text
        _parameterNames(5) = "@Established"
        _parameterVals(5) = ddlCoachingEstablished.SelectedValue
        _parameterNames(6) = "@DemoVideo"
        _parameterVals(6) = txtCoachingDemoVideo.Text
        _parameterNames(7) = "@Password"
        _parameterVals(7) = txtCoachingPassword.Text
         Try
        DataAccess.CRUD("UPDATE CoachingDetails SET Name=@Name,Address=@Address,Mob1=@Mob1,Mob2=@Mob2,L_Line=@LLine,Established=@Established,Demo_Video=@DemoVideo,Password=@Password,Step_Completed='True',Time_Stamp='" & Date.Now & "'", _parameterNames, _parameterVals)
    Catch ex As Exception

    End Try

现在我想在我的Primary Key Violation页面中捕获aspx.vb异常。但是我没有在aspx.vb页面中获得异常，因为类函数捕获了错误。那么，我如何从类文件中获取异常到aspx.vb文件？结束子

Answer 1

Rethrow。（http://www.selfelected.com/rethrow/）

Try
    ....
Catch ex As Exception 
    do some stuff with ex
    Throw    ' important to not use ex as parameter as that would start a new exception stack.
Finally
    do some other stuff
End Try

由于你没有在捕获中做任何事情，只需跳过它。

Try
    ....
Finally
    do some other stuff
End Try

要使代码更好，请在Using上阅读。使用您可以让编译器为您隐式插入Try / Finally。代码将类似于：

Using connection As SqlConnection = Global.Connection.GetDbConnection()
    Using command As New SqlCommand(sql, connection)
        If parameterNames IsNot Nothing Then
            For i = 0 To parameterNames.Length - 1
                command.Parameters.AddWithValue(parameterNames(i), parameterVals(i))
            Next
        End If
        noOfRowsAffected = _command.ExecuteNonQuery()
    End Using
End Using

请注意，我将所有变量都设为本地变量。这对你来说可能是不可能的，因为你对代码的了解比我知道的要多得多......（但代码建议你的变量在哪些类变量，但你还是将它们视为本地变量。）

同时查看Dapper。 Dapper是Stack溢出运行的东西。这是一个很好的小型库，可以让编写sql调用更容易编写和读取。

Answer 2

BCL没有可以被捕获的PrimaryKeyViolationException。

最接近的是捕获SqlException并查看消息以查看SQL Server报告的问题。对于Catch，Exception块应该 Try If _parameterNames IsNot Nothing Then For i = 0 To _parameterNames.Length - 1 _command.Parameters.AddWithValue(_parameterNames(i), _parameterVals(i)) Next End If _noOfRowsAffected = _command.ExecuteNonQuery() Catch ex As SqlException ' Do stuff - logging, checking the exception message etc... ' Rethrow exception if you want the exception to bubble up Catch ex As Exception 'MsgBox(ex.Message) _noOfRowsAffected = -1 Finally If _connection.State = ConnectionState.Open Then _connection.Close() _connection.Dispose() _command.Dispose() End If End Try的阻止块，因为它更具体。

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从类文件中捕获异常到aspx.vb页面

2 个答案: