C# 如何将多个LINQ Include（）语句分配给变量以供代码重用？

我想在变量中存储一组

.include（）

语句，因为我需要在多个位置使用相同的

includes

。因此，为了防止代码重复，我提出以下问题：

例如，以下面的查询为例，我将在其中加载多个相关实体：

var record = await db.DisplacementDamageRecords
        .Include(tr => tr.Mission)
            .ThenInclude(m => m.MissionRadiationPartsLead)
        .Include(tr => tr.Mission)
            .ThenInclude(m => m.MissionInstruments)
                .ThenInclude(mi => mi.Instrument)
        .Include(tr => tr.Mission)
            .ThenInclude(m => m.MissionInstruments)
                .ThenInclude(mi => mi.CognitiveEngineer)
        .Include(tr => tr.ProcurementPart)
            .ThenInclude(pp => pp.Part)
        .FirstOrDefaultAsync(tr => tr.Id == form.Id);

提取

包含的内容将非常有用，如下所示：

var testRecordIncludes = 
        .Include(tr => tr.Mission)
            .ThenInclude(m => m.MissionRadiationPartsLead)
        .Include(tr => tr.Mission)
            .ThenInclude(m => m.MissionInstruments)
                .ThenInclude(mi => mi.Instrument)
        .Include(tr => tr.Mission)
            .ThenInclude(m => m.MissionInstruments)
                .ThenInclude(mi => mi.CognitiveEngineer)
        .Include(tr => tr.ProcurementPart)
            .ThenInclude(pp => pp.Part)

这样我就可以像这样使用这个变量：

var record = await db.DisplacementDamageRecords
         .testRecordIncludes()
         .FirstOrDefaultAsync(tr => tr.Id == form.Id);

这可能吗？谢谢
 您可以定义如下扩展方法：

public static class DbExtensions
 {
     public static IQueryable<DisplacementDamageRecord> TestRecordIncludes(this IQueryable<DisplacementDamageRecord> records)
     {
         return records
                  .Include(tr => tr.Mission)
                      .ThenInclude(m => m.MissionRadiationPartsLead)
                  .Include(tr => tr.Mission)
                      .ThenInclude(m => m.MissionInstruments)
                          .ThenInclude(mi => mi.Instrument)
                   .Include(tr => tr.Mission)
                      .ThenInclude(m => m.MissionInstruments)
                          .ThenInclude(mi => mi.CognitiveEngineer)
                   .Include(tr => tr.ProcurementPart)
                      .ThenInclude(pp => pp.Part);
     }
 }
我建议创建一个更通用的扩展方法，并根据需要在子类上调用它，或者在基类上保留子类默认应具有的导航属性作为nav属性数组

此扩展方法有两个参数，一个是要包含在查询中的导航属性列表，另一个是
includealrecords

    public virtual IQueryable<TEntity> GetAll(string[] includeNavProp = null, bool includeAllRecords = false)
    {
        IQueryable<TEntity> query = includeAllRecords ? TableNoTracking.IgnoreQueryFilters() : Table;

        if (includeNavProp != null)
        {
            query = includeNavProp.Aggregate(query, (current, includePath) => current.Include(includePath));
        }

        return query;
    }

也就是说，您可以用这种方式调用
GetAll

var ddr = db.DisplacementDamageRecords.GetAll(new []{ 
       "Mission.MissionRadiationPartsLead",
       "Mission.MissionInstruments.Instrument",
       "Mission.MissionInstruments.CognitiveEngineer",
       "Mission.ProcurementPart.Part")

现在取决于您如何对导航属性进行分组，以使其可重用

希望这对您有所帮助
您知道是否可以允许使用不同的类型吗？例如，我也将在
dynamictrorecord
类型上使用此选项。您在这里看到的include都是从
TestRecord
基类继承的。因此，如果我们将您的扩展名更改为type
TestRecord
correct，这应该会起作用。我不确定我是否理解这个问题。您可以定义多个扩展方法，您可以为每个可重用场景定义一个扩展方法。因此，在您的示例中，我们定义了一种类型的
IQueryable
。此类型（DisplacementDamagerRecord）继承自
TestRecord
的基类。您看到的所有
包含的
都是我的
TestRecord
类的成员。我还有另一个名为
dynamictrorecord
的
TestRecord
子类，我想对其使用此扩展方法。因此，理论上，如果我们将扩展方法定义为
IQueryable
，那么它应该适用于我的子类，仍然正确吗？我可以很快进行测试，只是想确认一下，我用一个解决方案更新了您提到的问题的答案。我必须将通用代码添加到TestRecordIncludes中，但除此之外，这是我需要的。谢谢！一旦更新，我将标记为正确
    public virtual IQueryable<TEntity> GetAll(string[] includeNavProp = null, bool includeAllRecords = false)
    {
        IQueryable<TEntity> query = includeAllRecords ? TableNoTracking.IgnoreQueryFilters() : Table;

        if (includeNavProp != null)
        {
            query = includeNavProp.Aggregate(query, (current, includePath) => current.Include(includePath));
        }

        return query;
    }

public abstract class BaseEntityTypeConfiguration<T> : IEntityTypeConfiguration<T> where T : BaseEntity
{
    public virtual void Configure(EntityTypeBuilder<T> builder)
    {
        builder.HasKey(p => p.Id);
        builder.Property(dt => dt.Id).UseSqlServerIdentityColumn();

        builder.Property(x => x.CreatedBy).HasMaxLength(50).IsRequired();
        builder.Property(x => x.CreatedOn).IsRequired();
        builder.Property(x => x.UpdatedBy).HasMaxLength(50).IsRequired();
        builder.Property(x => x.UpdatedOn).IsRequired();

        builder.HasQueryFilter(app => !app.IsDeleted);
    }
}

var ddr = db.DisplacementDamageRecords.GetAll(new []{ 
       "Mission.MissionRadiationPartsLead",
       "Mission.MissionInstruments.Instrument",
       "Mission.MissionInstruments.CognitiveEngineer",
       "Mission.ProcurementPart.Part")