用多个和可为空的列分组，C#Linq？ [关闭]

Question

我在 c# 中有一个如下列表：

COL1    COL2    COL3    COL4    COL5    COL6    COL7
----    ----    ----    ----    ----    ----    ----
1       8635    16      NULL    Design  64      Device type 
1       8635    16      NULL    Design  65      OS  
1       8635    16      NULL    Design  66      Form factor
1       8635    16      NULL    Design  67      Dimensions
----    ----    ----    ----    ----    ----    ----        
1       8635    17      NULL    Design1 64      Device type 
1       8635    17      NULL    Design1 65      OS  
1       8635    17      NULL    Design1 66      Form factor
1       8635    17      NULL    Design1 67      Dimensions

如何使用 linq 获得以下结果？

Group1:
Keys: 
    1       8635    16      NULL    Design
Items:
    64      Device type
    65      OS
    66      Form factor
    67      Dimensions

Group2:
Keys: 
    1       8635    17      NULL    Design1
Items:
    64      Device type 
    65      OS  
    66      Form factor
    67      Dimensions

我按照以下方式完成了它，但它只返回一个包含 8 个项目的组：

var groupedItems = myDataList
                .GroupBy(q =>
                    new
                    {
                        q.Col1,
                        q.Col2,
                        q.Col3,
                        q.Col4,
                        q.Col5
                    }).ToList();

group by 中使用的实际类是实体框架中的视图，我写了 7 列。
我想将它按 7 列分组：ObjectId、DeviceId、DeviceSpecificationCategoryId、DeviceSpecificationCategoryIsHidden、DeviceSpecificationCategoryName、DeviceSpecificationCategoryPersianName、DeviceSpecificationCategoryOrderNumberInDevicePage

[EntityFlag]
public partial class DevicePresentationView : BaseEntity
{
    [PrimaryKey]
    public int ObjectId { get; set; }
    [PrimaryKey]
    public int DeviceId { get; set; }
    public Nullable<int> DeviceSpecificationCategoryId { get; set; }
    public Nullable<bool> DeviceSpecificationCategoryIsHidden { get; set; }
    public string DeviceSpecificationCategoryName { get; set; }
    public string DeviceSpecificationCategoryPersianName { get; set; }
    public Nullable<int> DeviceSpecificationCategoryOrderNumberInDevicePage { get; set; }
    public Nullable<int> DeviceSpecificationItemId { get; set; }
    public string DeviceSpecificationItemName { get; set; }
    public string DeviceSpecificationItemPersianName { get; set; }
    public Nullable<bool> DeviceSpecificationItemIsHidden { get; set; }
    public Nullable<int> DeviceSpecificationItemOrderNumberInDevicePage { get; set; }
    public string DeviceSpecificationItemDescription { get; set; }
    public Nullable<bool> DeviceSpecificationItemIsPrimary { get; set; }
    public Nullable<bool> DeviceSpecificationItemIsEssential { get; set; }
    public string DeviceSpecificationItemUnitName { get; set; }
    public string DeviceSpecificationItemUnitPersianName { get; set; }
    public Nullable<int> DeviceSpecificationItemValueTypeId { get; set; }
    public Nullable<long> DeviceSpecificationValueId { get; set; }
    public string DeviceSpecificationValue { get; set; }
    public Nullable<double> DeviceSpecificationNumericValue { get; set; }
    public Nullable<int> DeviceBenchmarkCategoryId { get; set; }
    public Nullable<bool> DeviceBenchmarkCategoryIsHidden { get; set; }
    public string DeviceBenchmarkCategoryName { get; set; }
    public string DeviceBenchmarkCategoryPersianName { get; set; }
    public Nullable<int> DeviceBenchmarkCategoryOrderNumberInDevicePage { get; set; }
    public Nullable<int> DeviceBenchmarkCategoryParentId { get; set; }
    public string DeviceBenchmarkCategoryDescription { get; set; }
    public Nullable<int> DeviceBenchmarkItemId { get; set; }
    public string DeviceBenchmarkItemName { get; set; }
    public Nullable<bool> DeviceBenchmarkItemIsHidden { get; set; }
    public string DeviceBenchmarkItemPersianName { get; set; }
    public Nullable<int> DeviceBenchmarkItemOrderNumberInDevicePage { get; set; }
    public string DeviceBenchmarkItemDescription { get; set; }
    public Nullable<bool> DeviceBenchmarkItemIsPrimary { get; set; }
    public string DeviceBenchmarkItemUnitName { get; set; }
    public string DeviceBenchmarkItemUnitPersianName { get; set; }
    public Nullable<int> DeviceBenchmarkItemValueTypeId { get; set; }
    public Nullable<long> DeviceBenchmarkValueId { get; set; }
    public string DeviceBenchmarkValue { get; set; }
    public Nullable<double> DeviceBenchmarkNumericValue { get; set; }
    public Nullable<long> DeviceBenchmarkAttachmentId { get; set; }
}

Answer 1

为此，您还必须在 Col5 上进行分组，您可能错过了：

var groupedItems = myDataList
                .GroupBy(q =>
                    new
                    {
                        q.Col1,
                        q.Col2,
                        q.Col3,
                        q.Col4,
                        q.Col5  // notice this
                    }).ToList();

现在您可以对结果进行迭代以打印或使用 Keys 和 Group 对 Group 进行操作。

它会根据需要返回结果：