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F＃泛型约束(F# Generics Constraints)

 我在课堂上有这个方法：  
member this.GetDbSet<'TEntity, 'TDTO, 'TKey when 'TKey :> IEquatable<'TKey> and 'TEntity :> IEntity<'TKey> and 'TEntity : not struct and 'TDTO :> IDTO<'TKey> and 'TEntity : equality and 'TEntity : null and 'TDTO : equality and 'TDTO : null and 'TKey : equality>(repository : BaseRepository<'TEntity, 'TDTO, 'TKey>) = 
    repository.DbSetFuncGetter().Invoke(uow.Context())
 
 但是当我构建项目时，我得到了这个错误  
This code is not sufficiently generic. The type variable 'TEntity when 'TEntity :> IEntity<'TKey> and 'TEntity : not struct and 'TEntity : equality and 'TEntity : null and 'TKey :> IEquatable<'TKey> and 'TKey : equality could not be generalized because it would escape its scope.
 
 但所有的限制都存在。 我错过了什么吗？  
 编辑：  
 如果您需要更多代码：  
 https://github.com/Ar3sDevelopment/Caelan.Frameworks.BIZ/blob/fsharp/Caelan.Frameworks.BIZ/Classes.fs  
 这是开源项目 

I have this method on class: 
member this.GetDbSet<'TEntity, 'TDTO, 'TKey when 'TKey :> IEquatable<'TKey> and 'TEntity :> IEntity<'TKey> and 'TEntity : not struct and 'TDTO :> IDTO<'TKey> and 'TEntity : equality and 'TEntity : null and 'TDTO : equality and 'TDTO : null and 'TKey : equality>(repository : BaseRepository<'TEntity, 'TDTO, 'TKey>) = 
    repository.DbSetFuncGetter().Invoke(uow.Context())
 
but when I build the project I get this error 
This code is not sufficiently generic. The type variable 'TEntity when 'TEntity :> IEntity<'TKey> and 'TEntity : not struct and 'TEntity : equality and 'TEntity : null and 'TKey :> IEquatable<'TKey> and 'TKey : equality could not be generalized because it would escape its scope.
 
But all constraints are there. Am I missing something? 
Edit: 
If you need more code: 
https://github.com/Ar3sDevelopment/Caelan.Frameworks.BIZ/blob/fsharp/Caelan.Frameworks.BIZ/Classes.fs 
this is the open source project

原文：https://stackoverflow.com/questions/24430515

更新时间：2022-04-06 18:04

最满意答案

 当你有一个带有空格的图片url时，问题就会发生，而传递给css url（）的字符串不带引号 ：  
[style.background-image]="'url(' + photo + ')'"
 
 上面的代码在你的url没有空格时工作正常。 如果有空格只是用单引号包裹实际图像的URL：  
[style.background-image]="'url(\'' + photo + '\')'"
 
 顺便说一下 ，如果这仍然不起作用，请尝试禁用Angular的内置消毒处理以获取传入的值：  
bypassSecurityTrustStyle(style)
 
 你可以为此创建一个管道：  
import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer } from '@angular/platform-browser';

@Pipe({ name: 'safe' })
export class SafePipe implements PipeTransform {
  constructor(
    private sanitizer: DomSanitizer
  ) { }

  transform(style) {
    return this.sanitizer.bypassSecurityTrustStyle(style);
  }
}

The problem occurs when you have an image url with spaces in it and the string, which is passed to css url() is without quotes: 
[style.background-image]="'url(' + photo + ')'"
 
The code above works fine when your url has no spaces. If there are spaces just wrap actual image url with single quotes: 
[style.background-image]="'url(\'' + photo + '\')'"
 
By the way, if this still does not work, try disabling Angular's built-in sanitization for the value passed in: 
bypassSecurityTrustStyle(style)
 
You can create a pipe for that: 
import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer } from '@angular/platform-browser';

@Pipe({ name: 'safe' })
export class SafePipe implements PipeTransform {
  constructor(
    private sanitizer: DomSanitizer
  ) { }

  transform(style) {
    return this.sanitizer.bypassSecurityTrustStyle(style);
  }
}

F＃泛型约束(F# Generics Constraints)

最满意答案

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