小编rah*_*wla的帖子

我有使用实体框架的 c# WEB API - 我试图通过我的角度前端发出放置请求以模拟“签入”功能，但请求未通过。

这是我的 Web api 方法

   [HttpPut("checkin/{id}")]
    [AuthorizeRoles(Role.Administrator, Role.User)]
    public async Task<IActionResult> CheckIn(int id)
    {
        var reservation = await context.Reservations.FindAsync(id);
        var username = User.Identity.Name;

        if (reservation == null)
            return NotFound();

        // Ensure user is checking-in their own reservation and its not already checked-in
        if (reservation.UserName == username && reservation.CheckInDate == null)
        {
            reservation.CheckInDate = DateTime.Now;

            var count = await context.SaveChangesAsync();

            if (count < 1)
                return StatusCode((int)HttpStatusCode.InternalServerError);
        }

        return Ok();
    }

这是我的两个 .ts 文件，其中正在发起请求 - 注意：在第二种方法中，我决定手动传递 ID …

这是我的代码,我不确定为什么抛出错误 - 该方法应该在指针对象上操作并打印出它的值.

主要:

cout<<"Deleted item is: "<<displayRecord(tmp)/*tmp->entry*/<<endl;


void displayRecord(PRecord* pr) {
cout<<"Time: "<<pr->time<<"\tEntry data: \""<<pr->entry<<'"'<<endl;
}

header.h:

#include <iostream>
using namespace std;
struct PRecord {
long time;
string entry;
struct PRecord *link;
};

void displayRecord(PRecord* pr);

我收到此错误: error: no match for 'operator <<

 error: no match for 'operator<<' in 'std::operator<< [with _Traits = std::char_traits<char>](((std::basic_ostream<char, std::char_traits<char> >&)(& std::cout)), ((const char*)"Deleted item is: ")) << Priority_Queue::displayRecord(tmp)'
    /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:108: note: candidates are: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>& (*)(std::basic_ostream<_CharT, _Traits>&)) [with _CharT = char, …