Question

我有一个ASP.NET 2010应用程序命中SQL 2005数据库。我正在尝试动态构建存储过程，具体取决于在搜索屏幕上选择的值。我已经在.net＆amp;的previosu版本中多次这样做了。 sql没问题。但是，现在，我的IF语句始终表现得好像没有传入数据。我已经调试了应用程序，并确保正在设置数据。我应该注意，当我直接运行程序时，无论是否有数据，都会返回正确的数据。

这是一个相当简单的存储过程..

ALTER PROCEDURE get_cases_by_search_criteria
    @vin as varchar(30) = null
AS
declare @sqlstr varchar(1000)

set @sqlstr = 'SELECT 
[Case].CaseID, 
[Case].VIN, 
[Case].Make, 
[Case].Model, 
[Case].VehicleYear, 
if  @vin is not null and @vin <> ''
    set @sqlstr = @sqlstr + ' and ' + ('[Case].VIN = ''' + convert(varchar,@vin) + '''') 

exec(@sqlstr)

RETURN

以下是调用存储过程的代码...

 Public Function GetCases(ByVal oSearchCriteria As SearchCriteria) As List(Of BE.Case)

    Dim lstCase As New List(Of BE.Case)
    Dim oCase As BE.Case
    Dim oProviderFactory As New ProviderFactory
    Dim oConnection As DbConnection
    Dim oReader As System.Data.IDataReader
    Dim oFactory As DbProviderFactory
    Dim oCmd As DbCommand
    Dim param1 As System.Data.Common.DbParameter

    Try
        'call my class to get an instance of the DBProviderFactory class
        oFactory = oProviderFactory.GetFactory
        'call another class of mine. pass in the DBProviderFactory class which will create a non-provider-specific connection object
        oConnection = oProviderFactory.GetProviderConnection(oFactory)

        'non-specific create command
        oCmd = oConnection.CreateCommand

        'non-specific parameter
        If oSearchCriteria.VIN.Length = 0 Then
            param1 = oFactory.CreateParameter()
            param1.ParameterName = "@vin"
            param1.DbType = DbType.String
            param1.Value = DBNull.Value
            oCmd.Parameters.Add(param1)
        Else
            param1 = oFactory.CreateParameter()
            param1.ParameterName = "@vin"
            param1.DbType = DbType.String
            param1.Value = oSearchCriteria.VIN
            oCmd.Parameters.Add(param1)

        End If

        oCmd.CommandType = CommandType.StoredProcedure
        oCmd.CommandText = "get_cases_by_search_criteria"

        Using (oConnection)
            oConnection.Open()
            oReader = oCmd.ExecuteReader()

            While oReader.Read
                oCase = New BE.Case

                'Case
                If oReader("CaseID") IsNot System.DBNull.Value Then oCase.CaseID = oReader("CaseID")

                If oReader("Make") IsNot System.DBNull.Value Then oCase.Make = oReader("Make")
                If oReader("Model") IsNot System.DBNull.Value Then oCase.Model = oReader("Model")
                If oReader("VehicleYear") IsNot System.DBNull.Value Then oCase.VehicleYear = oReader("VehicleYear")
                If oReader("VIN") IsNot System.DBNull.Value Then oCase.VIN = oReader("VIN")

                lstCase.Add(oCase)
            End While

            oConnection.Close()
        End Using
    Catch ex As Exception
        Throw ex
    End Try
    Return lstCase
End Function

为什么我的存储过程总是认为有值？

0 个答案: