TypeScript:将泛型作为参数传递给泛型类 [英] TypeScript: pass generic type as parameter in generic class

问题描述

TypeScript: 我在DataProvider类中有一个方法，其中有一个方法getTableData:

TypeScript: I have a method in the DataProvider class with a method getTableData:

public static getTableData<T extends DataObject>(type: { new(): T}): Array<T> { ... }

这在我编写代码时非常有效:

this works perfectly when I code:

let speakers = DataProvider.getTableData(Speaker);  // where Speaker is a class

现在我要从通用类中调用它:

now I want to call this from a generic Class:

export class ViewModelBase<T extends DataObject> {   
  public getData(): Array<T> {
    return <T[]> DataProvider.getTableData(T);
  }
}

现在我收到传递给getTableData的T参数的找不到名称'T'错误.应该如何调用getTableData?

Now I get a Cannot find name 'T' error for the T parameter I pass to getTableData. How should getTableData be called?

更新: 在@Paleo的帮助下，我想到了这一点:

update: With the help of @Paleo I came up this:

export class ViewModelBase<T extends DataObject> {   

  constructor(private dataObjectClass: { new(): T}){}

  public getTableData(): Array<T> {
    return <T[]> DataProvider.getTableData<T>(this.dataObjectClass);
  }
}

问题是，尽管我已经告诉过: class SpeakerViewModel extends ViewModelBase<Speaker> { ... } 我希望它成为Speaker的ViewModel，我仍然像SpeakerViewModel那样实例化:

the thing is that although I have already told in: class SpeakerViewModel extends ViewModelBase<Speaker> { ... } that I want it to be a ViewModel for Speaker I still have the instantiate the SpeakerViewModel like:

let vm = new SpeakerViewModel(Speaker);

尽管我已经告诉过所有有关Speaker的内容.我想我还是不太了解.

although I have already told it is all about Speaker. I guess I still don't fully understand this.

推荐答案

泛型只是元数据.调用函数时，不能将它们用作参数.也许您需要这样的东西:

Generics are just metadata. They cannot be used as parameters when calling a function. Maybe you need something like this:

export class ViewModelBase<T extends DataObject> {
  constructor(private Cl: {new(): T}) {
  }
  public getData(): Array<T> {
    return DataProvider.getTableData<T>(this.Cl);
  }
}

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