如何從 ASP.NET 核心為任意參數執行 [HttpGet]

Question

我用 APS.NET core 和 CRUD 原理學習 Angular

我有這兩種方法，例如：

/// <summary>
/// Retrieve all items from Books.
/// </summary>
/// <returns>Books items List</returns>
// GET: api/BooksXml
[HttpGet]
public IActionResult GetBookItems()
{
    List<BookItem> BookItems = new List<BookItem>();
    XDocument doc = _db.GetXmlDb();
    List<BookItem> bookitems = doc.Descendants("book").Select(x => new BookItem()
    {
        Id = (string)x.Attribute("id"),
        Author = (string)x.Element("author"),
        Title = (string)x.Element("title"),
        Genre = (string)x.Element("genre"),
        Price = (decimal)x.Element("price"),
        Publish_date = (DateTime)x.Element("publish_date"),
        Description = (string)x.Element("description")
    }).ToList();
    return Ok(bookitems);
}

/// <summary>
/// Returns a Book item matching the given id.
/// </summary>
/// <param name="id">Id of item to be retrieved</param>
/// <returns>Book item</returns>
// GET: api/BooksXml/5
[HttpGet("{id}")]
public IActionResult GetBookItems(string id)
{
    XDocument doc = _db.GetXmlDb();
    XElement result = doc.Descendants("book").FirstOrDefault(el => el.Attribute("id") != null &&
                 el.Attribute("id").Value == id);
    List<BookItem> BookItems = new List<BookItem>();
    if (result != null)
    {
        BookItem Book = new BookItem();
        Book.Id = (string)result.Attribute("id");
        Book.Author = (string)result.Element("author");
        Book.Title = (string)result.Element("title");
        Book.Genre = (string)result.Element("genre");
        Book.Price = (decimal)result.Element("price");
        Book.Publish_date = (DateTime)result.Element("publish_date");
        Book.Description = (string)result.Element("description");
        BookItems.Add(Book);

    }
    return Ok(BookItems);
}

它們都是正確的 get 方法，我更想要的是有另一個帶有路線的 get，這樣我就可以在我的后端書籍數據庫中搜索書名。

像這樣：（BooksXmlController.cs）

 /** GET all books from server. */
  getBookItems(): Observable<BookItem[]> {
    return this.http.get<BookItem[]>(this.BookItemsUrl);
  }

  /** GET book by id. */
  getBookItem(id: string): Observable<BookItem[]> {
    const url = `${this.BookItemsUrl}/${id}`;
    return this.http.get<BookItem[]>(url);
  }

  /** GET book by title from server. */
  getBookByTitle(title: string): Observable<BookItem> {
    const url = `${this.BookItemsUrl}/${title}`;
    return this.http.get<BookItem>(url);
  }

注意getBookByTitle ，如何將“標題”映射到 ASP.NET 核心后端 [HttpGet]

Answer 1

在您的控制器中添加另一個接受字符串作為參數的操作：

[HttpGet]
public IActionResult GetBookItemsByTitle(string title)
{
}

如果你想調用這個動作，url 將是：

 const url = `${this.BookItemsUrl}?title=${title}`;

我建議查看ASP.NET Core 中的路由。

編輯：

如果要重用當前存在的代碼，請從路由中刪除{id}並添加標題：

[HttpGet]
public IActionResult GetBookItems(string id, string title)
{
}

之后，您可以使用這些 URL 調用您的方法：

const url = `${this.BookItemsUrl}?id=${id}`;
const url = `${this.BookItemsUrl}?title=${title}`;
const url = `${this.BookItemsUrl}?id=${id}&title=${title}`;

Answer 2

您可以通過定義路由約束來嘗試這個

int 約束，因此您的路線將只接受 int id

[HttpGet("{id:int}")]
public IActionResult GetBookItems(int id)

alpha 代表（只接受字母）

[HttpGet("{title:alpha}")]
public GetBookByTitle(string title)