Question

我有一种方法可以将一些动态排序应用于IQueryable。以下是相关代码：

if (orderBy != 0)
{
    if (thenBy != 0 && thenBy != orderBy)
    {
        results = results.OrderBy(request.OrderBy + " ASC, " + request.ThenBy + " ASC");
    }
    else if (thenByDesc != 0 && thenByDesc != orderBy)
    {
        results = results.OrderBy(request.OrderBy + " ASC, " + request.ThenByDesc + " DESC");
    }
    else
    {
        results = results.OrderBy(request.OrderBy + " ASC");
    }
}

问题是订购似乎没有正常工作。例如，按财产排序＆＃34;名称＆＃34;这只是一个字符串，似乎无法工作。

我在确定排序之前找到了toList()结果的修复，如下所示：

orderedResults = results.ToList().AsQueryable();

然后在orderedResults变量上执行OrderBy。这样会很好，但我订购的结果可能包含1000个项目。在这种情况下的表现非常糟糕。是否有其他解决方案没有将集合带入内存？

更新

事后看来，我发布的代码并不清楚。这是整个方法：

public static IOrderedQueryable<TSource> Order<TSource, TOrdering>(this IQueryable<TSource> results, RequestBase<TOrdering> request)
    {
        var genericType = typeof(TOrdering);
        if (!genericType.IsEnum) return (IOrderedQueryable<TSource>)results;

        var orderBy = Convert.ToInt32(request.OrderBy as Enum);
        var orderByDesc = Convert.ToInt32(request.OrderByDesc as Enum);
        var thenBy = Convert.ToInt32(request.ThenBy as Enum);
        var thenByDesc = Convert.ToInt32(request.ThenByDesc as Enum);

        if (orderBy != 0)
        {
            if (thenBy != 0 && thenBy != orderBy)
            {
                results = results.OrderBy(request.OrderBy + " ASC, " + request.ThenBy + " ASC");
            }
            else if (thenByDesc != 0 && thenByDesc != orderBy)
            {
                results = results.OrderBy(request.OrderBy + " ASC, " + request.ThenByDesc + " DESC");
            }
            else
            {
                results = results.OrderBy(request.OrderBy + " ASC");
            }
        }
        else if (orderByDesc != 0)
        {
            if (thenBy != 0 && thenBy != orderByDesc)
            {
                results = results.OrderBy(request.OrderByDesc + " DESC, " + request.ThenBy + " ASC");
            }
            else if (thenByDesc != 0 && thenByDesc != orderByDesc)
            {
                results = results.OrderBy(request.OrderByDesc + " DESC, " + request.ThenByDesc + " DESC");
            }
            else
            {
                results = results.OrderBy(request.OrderByDesc + " DESC");
            }
        }

        return (IOrderedQueryable<TSource>)results;
    }

request.OrderBy和其他排序属性是枚举。此枚举可以包含诸如＆＃39; Name＆＃39;，＆＃39; SubmittedDate＆＃39;等值，以便在其上订购results。这就是我调用方法的方法：

reportsResponses = reportsResponses.Order(request);

更新2

有关代码的更多信息。我提到如果我在应用任何订购之前首先执行此操作，则排序有效：

results = results.ToList().AsQueryable();

在此之前，结果是从mongo驱动程序计算的。我们通过查询mongodb获得结果。 mongo在这里是薄弱环节吗？

动态Linq排序未在某些属性上正确排序

0 个答案: