<p>我使用VS2017的15.9.38版本。最近我在構建一個舊專案時開始出現錯誤。這是一個有Angular應用程式的Web專案。這個錯誤是：</p> <blockquo-有解無憂

我有如下代碼：

public static class IntegrationServiceExtensions
{
    public static IQueryable<T> LearningObjectContainerIncludeNestedProperties<T>(this IQueryable< T> query) where T : LearningObjectContainer
    {
        query.Include(x => x.Bases)
            .Include(x => x.LearningObjectives).ThenInclude(x => x.Classifications)
            .Include(x => x.Classifications)
            .Include(x => x.ContainerPropertyImplementations)。

        return查詢。
    }
}

//Include不作業。
public async Task<LearningObjectContainer> GetLearningObjectContainer(int id)。
{
    var query = _applicationDbContext.LearningObjectContainers.LearningObjectContainerIncludeNestedProperties（）。

    var learningObjectContainer = await query.FirstOrDefaultAsync(x => x.Id == id);

    return learningObjectContainer;
}

//包括作業。
public async Task<LearningObjectContainer> GetLearningObjectContainer(int id)。
{
    var query = _applicationDbContext.LearningObjectContainers
        .Include(x => x.Bases)
        .Include(x => x.LearningObjectives).ThenInclude(x => x.Classifications)
        .Include(x => x.Classifications)
        .Include(x => x.ContainerPropertyImplementations)。

    var learningObjectContainer = await query.FirstOrDefaultAsync(x => x.Id == id);

    return learningObjectContainer;

為什么在使用擴展方法時，我不能使用急切的加載？

https://docs.microsoft.com/en-us/ef/core/querying/related-data/eager

我試著用急于加載的方式進行分割查詢，但沒有成功。

public static IQueryable< T> LearningObjectContainerIncludeNestedProperties< T>(this IQueryable<T> query) where T : LearningObjectContainer
{
    query.Include(x => x.Bases)
        .Include(x => x.LearningObjectives).ThenInclude(x => x.Classifications)
        .Include(x => x.Classifications)
        .Include(x => x.ContainerPropertyImplementations)
        .AsSplitQuery()。

    return查詢。
}

https://docs.microsoft.com/en-us/ef/core/querying/single-split-queries

uj5u.com熱心網友回復：

我認為這種方法應該是：

public static IQueryable< T> LearningObjectContainerIncludeNestedProperties< T>(this IQueryable<T> query) where T : LearningObjectContainer
{
    query = query.Include(x => x.Bases)
        .Include(x => x.LearningObjectives).ThenInclude(x => x.Classifications)
        .Include(x => x.Classifications)
        .Include(x => x.ContainerPropertyImplementations)。

    return查詢。
}

它只是缺少對IQueryable結果的查詢重新賦值/w Include。("query = ")

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