处理 EF 存储过程的多个结果集的通用方法

• EF 6、.NET 4.51

我正在尝试构建一个通用帮助程序类，它将帮助我将每个结果集“翻译”为类型安全类，如此处所述使用 SqlQuery 处理存储过程的多个结果 https://stackoverflow.com/questions/25304791/handle-multiple-result-from-a-stored-procedure-with-sqlquery/25305607#25305607

对于我的解决方案，我想将以下内容传递给我的帮助器类（MultiResultsetsHelper）：

1. 通用返回类型
2. 对象上下文
3. 数据读取器
4. 班级类型列表in order返回的结果集的数量

然后让辅助类完成填充 1 的繁重工作。下面是到目前为止的代码：

结果类

public class Set1ReturnDto
{
    public int CruiseCount { get; set; }
    public string DisplayText { get; set; }
    public int DisplayValue { get; set; }
}

public class Set2ReturnDto
{
    public string DepartingFrom { get; set; }
    public string Port_Code { get; set; }
}

public class DummyReturnDto
{
    public DummyReturnDto()
    {
        Set1 = new List<Set1ReturnDto>();
        Set2 = new List<Set2ReturnDto>();
    }

    public List<Set1ReturnDto> Set1 { get; set; }
    public List<Set2ReturnDto> Set2 { get; set; }
}

低级数据库调用

    public static DummyReturnDto DonoUspGetSideBarList(DbContext aDbContext, out int aProcResult)
    {
        SqlParameter procResultParam = new SqlParameter { ParameterName = "@procResult", SqlDbType = SqlDbType.Int, Direction = ParameterDirection.Output };

        DbCommand dbCommand = aDbContext.Database.Connection.CreateCommand();
        dbCommand.Parameters.Add(procResultParam);
        dbCommand.CommandText = "EXEC @procResult = [dbo].[usp_GetSideBarList] ";
        dbCommand.Transaction = aDbContext.Database.CurrentTransaction.UnderlyingTransaction;

        DbDataReader reader = dbCommand.ExecuteReader();
        aProcResult = -1;

        // Drop down to the wrapped `ObjectContext` to get access to the `Translate` method
        ObjectContext objectContext = ((IObjectContextAdapter)aDbContext).ObjectContext;

        List<Type> containedDtos = new List<Type>
                                   {
                                       typeof (List<Set1ReturnDto>), 
                                       typeof (List<Set1ReturnDto>)
                                   };

        return MultiResultsetsHelper.Process<DummyReturnDto>(reader, objectContext, containedDtos);
    }

返回的结果数据集是：

助手类

public static class MultiResultsetsHelper
{
    /// <summary>
    ///     Given a data reader that contains multiple result sets, use the supplied object context to serialise the
    ///     rows of data in the result set into our property.
    /// </summary>
    /// <typeparam name="T">Type of the containing object that contains all the various result sets.</typeparam>
    /// <param name="aDbReader">Database reader that contains all the result sets returned from the database.</param>
    /// <param name="aObjectContext">Data context associated with the data reader.</param>
    /// <param name="aContainedDataSetReturnedTypes">
    ///     List of types in order of which the result sets are contained within the
    ///     data reader. We will serilize sequentially each result set the data reader contains
    /// </param>
    /// <returns>Retuns an object representing all the result sets returned by the data reader.</returns>
    public static T Process<T>(DbDataReader aDbReader, ObjectContext aObjectContext, List<Type> aContainedDataSetReturnedTypes) where T : new()
    {
        //What we will be returning
        T result = new T();

        for (int datasetNdx = 0; datasetNdx < aContainedDataSetReturnedTypes.Count; datasetNdx++)
        {
            //Advance the reader if we are not looking at the first dataset
            if (datasetNdx != 0)
                aDbReader.NextResult();

            //Get the property we are going to be updating based on the type of the class we will be filling
            PropertyInfo propertyInfo = typeof (T).GetProperties().Single(p => p.PropertyType == aContainedDataSetReturnedTypes[datasetNdx]);

            //Now get the object context to deserialize what is in the resultset into our type
            var valueForProperty = aObjectContext.Translate <aContainedDataSetReturnedTypes[datasetNdx]> (aDbReader);

            //Finally we update the property with the type safe information
            propertyInfo.SetValue(result, valueForProperty, null);
        }
        return result;
    }
}

但目前我无法编译它。

错误 2 运算符“

有人可以帮忙吗？最终，它与我们如何使用反射和传入的 ContainedDataSetReturnedTypes 有关。我很乐意改变一切，只要调用 MultiResultsetsHelper.Process() 仍然很容易

这段代码：

aObjectContext.Translate<aContainedDataSetReturnedTypes[datasetNdx]>

不起作用，因为泛型类型参数总是在编译时解析。你不能通过Type运行时的实例。

您仍然可以调用泛型方法，但您必须使用反射 https://stackoverflow.com/questions/232535/how-to-use-reflection-to-call-generic-method.