Asp.net 500 内部服务器错误和 C# Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException

如何解决Asp.net 500 内部服务器错误和 C# Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException

当我尝试更新汽车时出现以下错误：

添加没有问题，但是更新没有完成。要更新的产品是打印控制台的时候来的，更新的时候就变了，但是后台报错，我得到了500internal服务器错误

C# Dberror

500 and name length error

汽车更新组件代码：

import { Component,OnInit } from '@angular/core';
import { FormBuilder,FormGroup,Validators } from '@angular/forms';
import { ActivatedRoute } from '@angular/router';
import { ToastrService } from 'ngx-toastr';
import { Car } from 'src/app/models/car';
import { CarService } from 'src/app/services/car.service';

@Component({
  selector: 'app-car-update',templateUrl: './car-update.component.html',styleUrls: ['./car-update.component.css']
})
export class CarUpdateComponent implements OnInit {

  constructor(private carService:CarService,private formBuilder:FormBuilder,private toastrService:ToastrService,private activetedRoute:ActivatedRoute) { }

  car:Car[];
  carId:number;
  carUpdateForm:FormGroup;

  ngOnInit(): void {
    this.activetedRoute.params.subscribe(params=>{
      if(params["carId"]){
        this.carId=params["carId"];
        this.createCarUpdateForm(params["carId"]);
        this.getCarDetails(params["carId"]);
      }
    })

  }

getCarDetails(carId:number)
  {
    this.carService.getCarDetail(carId).subscribe(response => {
      this.car = response.data;
      console.log(response);
    })
  }

  createCarUpdateForm(carId:number){
    this.carUpdateForm=this.formBuilder.group({
        carName:["",Validators.required],brandId:["",colorId:["",unitPrice:["",Validators.required]
    })      
  }
  
  
  update(){
    if(this.carUpdateForm.valid){
      let car = Object.assign({},this.carUpdateForm.value)
      car.carId=this.carId;
      console.log(car)
      this.carService.update(car).subscribe(data=>{
        this.toastrService.success(data.message,"Başarılı")
      },dataError=>{
        if(dataError.error.Errors.length>0){
          for (let i = 0; i < dataError.error.Errors.length; i++) {
            
              this.toastrService.error(dataError.error.Errors[i].ErrorMessage,"Doğrulama Hatası")
          }
        }
      })
    }else{
      this.toastrService.error("Formunuz eksik","Dikkat")
    }
  }
  

}

汽车更新-HTML代码

<div class="content" style="width: 300px;">


    <div class="col-md-12">
        <div class="card">
            <div class="card-header"><h5 class="title">araba Güncelle</h5></div>
            <div  class="card-body">
                <form [formGroup]="carUpdateForm">
  
                   
  
                    <div class="mb-3">
                        <label  for="carName">araba Adı</label>
  
                         <div  class="form-group">
                             <input type="text" id="carName" formControlName="carName" class="form-control" placeholder="carName"/>  <!--ilişkilendirme formControlName ile yapılır-->
                         </div>
                    </div>
                   
                    <div class="mb-3">
                        <label for="brandId">Marka numarası</label>
  
                        <div class="form-group">
                            <input type="number" id="brandId" formControlName="brandId" class="form-control" placeholder="colorId"/>  <!--ilişkilendirme formControlName ile yapılır-->
                        </div>
                    </div>
                   
                    <div class="mb-3">
                        <label for="colorId">Renk numarası</label>
  
                        <div class="form-group">
                            <input type="number" id="colorId" formControlName="colorId" class="form-control" placeholder="colorName"/>  <!--ilişkilendirme formControlName ile yapılır-->
                        </div>
                    </div>
                    
                    <div class="mb-3">
                        <label for="unitPrice">Birim Fiyatı</label>
  
                        <div class="form-group">
                            <input type="number" id="unitPrice" formControlName="unitPrice" class="form-control" placeholder="unitPrice"/>  <!--ilişkilendirme formControlName ile yapılır-->
                        </div>
                    </div>
                   
  
                </form>
  
            </div>
            <div class="card-footer">
  
                <button class="btn btn-fill btn-primary" (click)="update()">Güncelle</button>
  
            </div>
        </div>
  
  
    </div>
  
   
  
  </div>
  

汽车服务

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs';
import { Car } from '../models/car';
import { ListResponseModel } from '../models/listResponseModel';
import { ResponseModel } from '../models/responseModel';

@Injectable({
  providedIn: 'root'
})
export class CarService {
  
  apiUrl = "https://localhost:44352/api/";

  constructor(private httpClient: HttpClient) { }

  getCars():Observable<ListResponseModel<Car>> {
    let newPath = this.apiUrl + "cars/getcardetails"
    return this.httpClient.get<ListResponseModel<Car>>(newPath);
  }

  getCarsByBrand(brandId:number):Observable<ListResponseModel<Car>> {
    let newPath = this.apiUrl + "cars/getcardetailsbybrand?brandId="+brandId;

    return this.httpClient.get<ListResponseModel<Car>>(newPath);
  }
  getCarsByColor(colorId:number):Observable<ListResponseModel<Car>>{
    let newPath = this.apiUrl + "cars/getcardetailsbycolor?colorId="+colorId;

    return this.httpClient.get<ListResponseModel<Car>>(newPath);
  }

  getCarsByColorAndBrand(colorId:number,brandId:number):Observable<ListResponseModel<Car>>{

    let newPath = this.apiUrl + "cars/getcarsbycolorandbrand?brandId="+brandId+"colorId="+colorId;

    return this.httpClient.get<ListResponseModel<Car>>(newPath);
  }

  getCarDetail(carId:number):Observable<ListResponseModel<Car>>{
    let newPath = this.apiUrl + "cars/getcardetail?carId=" + carId;
    return this.httpClient.get<ListResponseModel<Car>>(newPath);
  }
  
  add(car:Car):Observable<ResponseModel>{
    return this.httpClient.post<ResponseModel>(this.apiUrl+"cars/add",car)
  }

  update(car:Car):Observable<ResponseModel>{
    console.log(car)
    return this.httpClient.post<ResponseModel>(this.apiUrl+"cars/update",car)
  }
}

汽车控制器

 [HttpPost("update")]
        public IActionResult Update(Car car)
        {
            var result = _carService.Update(car);
            if (result.Success)
            {
                return Ok(result);
            }

            return BadRequest(result.Message);
        }