小编jen*_*ent的帖子

我有这个结构

Customer
 - has many Orders
  - has many OrderItems

我想生成一个CustomerItemsvia LINQ 列表给出一个子集OrderItems:

List of new { Customer, List<OrderItem> Items }

这是客户从商品子集中订购的所有商品的分组

我如何使用LINQ来跟踪客户的订单和分组以生成此对象？

到目前为止,我有点像

items
 .GroupBy(i => i, i => i.Order.Customer, (i, customer) => new {customer, i})

但那显然不是列表.我猜我在那里需要一个SelectMany,但是可以用一些指针来做.

我用Google搜索并环顾四周有没有人知道任何隐藏的宝石,这不是谷歌搜索的前几页....

试图让angular-cli识别出多个配置 angular.json

C:\_dev\myapp>ng serve --configuration development
Configuration 'development' could not be found in project 'myapp'.
Error: Configuration 'development' could not be found in project 'myapp'.

该片段是:

    "configurations": {
        "production": {
          "fileReplacements": [
            {
              "replace": "src/environments/environment.ts",
              "with": "src/environments/environment.production.ts"
            }
          ],
          "optimization": true,
          "outputHashing": "all",
          "sourceMap": false,
          "extractCss": true,
          "namedChunks": false,
          "aot": true,
          "extractLicenses": true,
          "vendorChunk": false,
          "buildOptimizer": true
        },
        "development": {
          "fileReplacements": [
            {
              "replace": "src/environments/environment.ts",
              "with": "src/environments/environment.development.ts"
            }
          ],
          "optimization": false,
          "outputHashing": "all",
          "sourceMap": true,
          "extractCss": true,
          "namedChunks": true,
          "aot": …

我在本地测试应用内订阅产品时遇到此错误.

验证是必需的.您需要登录您的Google帐户

我能够检查产品的库存但不应该也能购买它吗？

有很多帖子说明为什么会出现这个错误,我认为这个问题得到解决:

• 该产品已在测试版渠道发布,并启用了应用内结算功能
• 我使用设备上的测试用户许可帐户登录Play商店.

是通过beta/alpha频道测试实际购买的唯一方法 - 不是直接来自android studio.这篇文章表明它有可能(见屏幕截图)

http://developer.android.com/google/play/billing/billing_testing.html#billing-testing-test

当只能在运行时推断类型时,您将如何使用反射来执行以下方法？

MainObject.TheMethod<T>(Action<OtherObject<T>>)

在日常使用中,通常:

mainObject.Method<Message>(m => m.Do("Something"))

因此,给定一个类型列表,我需要在上面的方法中将它们替换为T并调用.

这是我在变成腻子之前得到的地方:

var mapped = typeof(Action<OtherObject<>>).MakeGenericType(t.GetType());
Activator.CreateInstance(mapped,  new object[] { erm do something?});

typeof(OtherObject)
    .GetMethod("TheMethod")
    .MakeGenericMethod(t.GetType())
    .Invoke(model, new object[] { new mapped(m => m.Do("Something")) });

更新:为了澄清,我有一个类型列表,我希望为每个类型执行相同的已知方法.伪代码:

foreach(var t in types)
{
    mainObject.TheMethod<t>(mo => mo.Do("Something"))
}

(TheMethod()的参数类型Action<OtherObject<T>>如上所述)

FluentNHibernate.Automapping.AutoPersistenceModel Override<T>(System.Action<AutoMapping<T>> populateMap)

行动是一样的 AutoMapping<T>.Where("something")

model.Override<Message>(m => m.Where("DeletedById is null"))

现在,为一堆类型做到这一点:)

任何人都可以解释为什么实体连接而不是id生成一些非常丑陋的SQL实际上在概念上它做你认为是同样的事情？例如

通过id

from companyDirector in CompanyDirectors
join contactAddress in ContactAddresses
  on companyDirector.ContactAddress.Id equals contactAddress.Id
select new {companyDirector, contactAddress}

生成

FROM  [COMPANY] AS [Extent1]
    INNER JOIN [ADDRESS] AS [Extent2] ON [Extent1].[CONTACT_ADDRESS_ID] = [Extent2].[CONTACT_ADDRESS_ID]

通过实例

from companyDirector in CompanyDirectors
join contactAddress in ContactAddresses
  on companyDirector.ContactAddress equals contactAddress
select new {companyDirector, contactAddress}

生成

FROM  [COMPANY] AS [Extent1]
INNER JOIN [ADDRESS] AS [Extent2] ON  EXISTS (SELECT 
    1 AS [C1]
    FROM    ( SELECT 1 AS X ) AS [SingleRowTable1]
    LEFT OUTER JOIN  (SELECT 
        [Extent3].[CONTACT_ADDRESS_ID] AS …

我有3个根组件,由root引导AppModule.

你如何@Input()为其中一个组件指定参数？

也不

<app-modal [id]="'hard-coded value'"></app-modal>
<app-modal [id]="constantExportedByAppmodule"></app-modal>

通过AppModalComponent以下方式获取:

@Input() id: string;

这是未定义的.

我想知道是否可以挂钩angular-cli的build/watch命令:

ng build/w

它生成文件并将它们放在项目的/dist文件夹中

我只是想在构建完成后将dist文件夹复制到另一个目录,是否可能？

我有以下指令应用于输入标记.当在主机组件上运行jasmine规范时,我希望它忽略(模拟)这个指令,因为它依赖于我对测试不感兴趣的jquery.

我试图创建一个MockDirective类,但没有成功.谁知道怎么做到这一点？

@Directive({
    selector: '[skinColorPicker]'
})
export class ColorPickerDirective implements OnInit {

    @Input('skinColorPicker') initialColor;

    @Output() colorSelected: EventEmitter<string> = new EventEmitter<string>();

    constructor(private el: ElementRef) {}

    ngOnInit() {

       // legacy jQuery blah blah
    }
}

在主持人内:

<input skinColorPicker="'#555'" (colorSelected)="onPageBackgroundColorSelected($event)" 
 />

规格:

describe('PrintSidebarComponent', () => {
  let component: PrintSidebarComponent;
  let fixture: ComponentFixture<PrintSidebarComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [
          PrintSidebarComponent,
          MockDirective({ selector: '[skinColorPicker]' }) // does not work
      ]
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(PrintSidebarComponent);
    component = fixture.componentInstance;
    fixture.detectChanges(); …

我已经浏览了文档，但找不到帮助程序来重置 Luxon DateTime 的时间。

我可以从一个标准日期开始：

export const getDateOnly = (date: Date = new Date()) =>  new Date(
  date.getFullYear(),
  date.getMonth(),
  date.getDate()
)

export const today = () => DateTime.fromJSDate(getDateOnly());

但这似乎是一个常见的场景，我可能只是错过了它？