Crud operations in angular 7 using web API

Introduction :

Before going to perform the curd operation we have to learn about $http services in Angular now we will perform Crud operations in angular 7 using web API for employee and department.

Step 1: Creating tables for Employee and Department in SQL Server

Crud operations in angular 7 using web API

Step 2: Create ADO.NET Entity Data model & Create API’s

Step 3: Creating API’s using entity framework and Add Filename as given below for departments

File: ManageDepartmentController.cs

public class ManageDepartmentController : ApiController
    {
        EmpDeptDBEntities context = new EmpDeptDBEntities();
        // GET: api/ManageDepartment
        public IEnumerable<Department> Get()
        {
            return context.Departments;
        }
        // GET: api/ManageDepartment/5
        public Department Get(int id)
        {
            return context.Departments.Find(id);
        }
        // POST: api/ManageDepartment
        public IEnumerable<Department> AddDepartment([FromBody]Department dept)
        {
            context.Departments.Add(dept);
            context.SaveChanges();
            return Get();
        }

        // PUT: api/ManageDepartment/5
        public IEnumerable<Department> Put([FromBody]Department dept)
        {
            Department oldDept = context.Departments.Find(dept.DeptId);
            context.Entry(oldDept).CurrentValues.SetValues(dept);
            context.SaveChanges();
            return Get();
        }
        // DELETE: api/ManageDepartment/5
        public IEnumerable<Department> Delete(int id)
        {
            context.Departments.Remove(Get(id));
            context.SaveChanges();
            return Get();
        }
    }

• Add API controller name As given below for employee

File: ManageEmployeeController.cs

public class ManageEmployeeController : ApiController
    {
        EmpDeptDBEntities context = new EmpDeptDBEntities();
        public List<Employee> Get()
        {
            List<Employee> lstEmp = context.Employees.ToList();
            return lstEmp;
        }
        public Employee Get(int id)
        {
            return context.Employees.Find(id);
        }
        public List<Employee> AddEmployee(Employee emp)
        {
            context.Employees.Add(emp);
            context.SaveChanges();
            return Get();
        }
        public List<Employee> Put([FromBody]Employee emp)
        {
            Employee oldEmp = Get(emp.EmpId);
            context.Entry(oldEmp).CurrentValues.SetValues(emp);
            context.SaveChanges();
            return Get();
        }
        public List<Employee> Delete(int id)
        {
            context.Employees.Remove(Get(id));
            context.SaveChanges();
            return Get();
        }
    }

Step4: Set up the application with quick start files from GitHub, for installation please refer introduction.

Step5: Create a directory structure for angular application

Step6: Creating models for Employee and Department file name as given below

File: app.models.ts

export class Department {
    DeptId: number;
    DeptName: string;
}

export class Employee {
    EmpId: number;
    EmpName: string;
    EmpSalary: number;
    FKDeptId: number;
    Department: Department;
    constructor() {
    }
}

• Creating a root component with selector “File: app.component.ts“

import { Component,OnInit,Input } from '@angular/core';
@Component({
    selector: 'my-app',
    templateUrl: './template.html',
   })
export class AppComponent{  }

File: template.html

<div class="clearfix"> </div>
<div class="container">
    <h1>Employee Management</h1>
    <nav>
        <button class="btn btn-warning" routerLink="emp">Employees</button>
        <button class="btn btn-warning" routerLink="dept">Departments</button>
    </nav>
    <router-outlet></router-outlet>
</div>

Step 7: Creating component, service and template for Department

app.DeptService.ts

import { Http, Response,RequestOptions,Headers } from '@angular/http';
import { Injectable } from '@angular/core';
import 'rxjs/add/operator/map';
import { Observable } from 'rxjs/observable';
import { Department } from './../app.models';

@Injectable()
export class DeptService {
    departments: Department[];
    constructor(private http: Http) {
    }
    GetDepartments(): Observable<Department[]> {
        return this.http.get("/api/ManageDepartment").map((res: Response) => res.json());
    }
    GetDepartment(deptId: any): Observable<Department> {
        const url = `${'/api/ManageDepartment'}/${deptId}`;
        return this.http.get(url).map((res: Response) => res.json());
    }
    AddDepartment(dept: Department): Observable<Department[]>{
        let data = JSON.stringify(dept);
        let headers: Headers = new Headers({ "content-type": "application/json" });
        let options: RequestOptions = new RequestOptions({ headers: headers });
       return this.http.post("/api/ManageDepartment/AddDepartment", data, options).map((res: Response) => res.json());
    }
    UpdateDepartment(dept: Department): Observable<Department[]> {
        const url = `${'/api/ManageDepartment'}/${dept.DeptId}`;
        let data = JSON.stringify(dept);
        let headers: Headers = new Headers({ "content-type": "application/json" });
        let options: RequestOptions = new RequestOptions({ headers: headers });
        return this.http.put(url, data, options).map((res: Response) => res.json());
    }
    DeleteDepartment(deptId: any): Observable<Department[]> {
        debugger;
        const url = `${'/api/ManageDepartment'}/${deptId}`;
        return this.http.delete(url).map((res: Response) => res.json());
    }
}

File: dept.component.ts

import { Component, OnInit, Input } from '@angular/core';
import { DeptService } from './app.DeptService';
import { Department } from './../app.models';
import { CommonModule } from '@angular/common';

@Component({
    templateUrl: './DeptTemplate.html',
    providers: [DeptService]
})
export class DeptComponent implements OnInit {
    departments: Department[];
    department: Department = new Department();
    action: string = "Add";
    constructor(private deptService: DeptService) { }
    ngOnInit() {
        this.GetDepartments();
    }
    Add() {
        this.action = "Add";
        this.department = new Department();
        this.GetDepartments();
    }
    GetDepartments() {
        this.deptService.GetDepartments().subscribe(depts => this.departments = depts);
    }
    GetDepartment(deptId: any) {
        this.deptService.GetDepartment(deptId).subscribe(dept => this.department = dept);
    }
    AddDepartment() {
        this.deptService.AddDepartment(this.department).subscribe(depts => this.departments = depts);
    }
    EditDepartment(deptId: any) {
        this.GetDepartment(deptId);
        this.action = "Edit";
    }
    UpdateDepartment() {
        this.deptService.UpdateDepartment(this.department).subscribe(depts => this.departments = depts);
    }
    DeleteDepartment(deptId: any) {
        debugger;
        this.deptService.DeleteDepartment(deptId).subscribe(depts => this.departments = depts);
    }
}

File: dept.routing.ts

Here we are maintaining separate routing for department to make this module lazy-loaded.

import { ModuleWithProviders } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { DeptComponent } from './dept.component';
const routes: Routes = [
    { path: '', component: DeptComponent }
];
export const routing: ModuleWithProviders = RouterModule.forChild(routes);

File: dept.module.ts

Here we must import CommonModule to use NgModel in lazy loaded module, and no need to import BrowserModule because we have already imported that in root NgModule.

import { NgModule } from '@angular/core';
import { DeptComponent } from './dept.component';
import { HttpModule } from '@angular/http';
import { FormsModule } from '@angular/forms';
import { routing } from './dept.routing';
import { CommonModule } from '@angular/common';

@NgModule({
    imports: [CommonModule, HttpModule, FormsModule, routing],
    declarations: [DeptComponent],
    bootstrap: [DeptComponent]
})
export class DeptModule { }

File: DeptTemplate.html

<div class="clearfix"> </div>
<div class="container">
    <button class="btn btn-primary" data-toggle="modal" data-target="#myModal" (click)="Add()">Add New</button>
    <div class="clearfix"> </div>
    <table class="table table-striped table-bordered" style="width:50%">
        <thead>
            <tr>
                <th>Department Name</th>                
                <th></th>
                <th></th>
            </tr>
        </thead>
        <tbody>
            <tr *ngFor="let dept of departments">
                <td>{{dept.DeptName}}</td>                
                <td><button type="button" class="btn btn-info" (click)="EditDepartment(dept.DeptId)" data-toggle="modal" data-target="#myModal">Edit</button> </td>
                <td><button type="button" class="btn btn-danger" (click)="GetDepartment(dept.DeptId)" data-toggle="modal" data-target="#deleteModal">Delete</button> </td>
            </tr>
        </tbody>
    </table>
    <div id="myModal" class="modal fade" role="dialog">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal">×</button>
                    <h4 class="modal-title">Add/Edit Department</h4>
                </div>
                <div class="modal-body">
                    <form name="addEditForm">
                        <div class="form-group">
                            <label for="empName">Department Name</label>
                            <input type="text" class="form-control" name="empName" id="empName" [(ngModel)]="department.DeptName" required />
                        </div>                       
                        <div class="form-group">
                            <button type="submit" class="btn btn-info" (click)="AddDepartment()" *ngIf="action=='Add'" data-dismiss="modal">Add</button>
                            <button type="submit" class="btn btn-info" (click)="UpdateDepartment()" *ngIf="action=='Edit'" data-dismiss="modal">Update</button>
                            <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                        </div>
                    </form>
                </div>
            </div>
        </div>
    </div>


    <div id="deleteModal" class="modal fade" role="dialog">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal">×</button>
                    <h4 class="modal-title">Are you sure want to delete?</h4>
                </div>
                <div class="modal-body">
                    Department Name: <b>{{department.DeptName}}</b>
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-danger" (click)="DeleteDepartment(department.DeptId)" data-dismiss="modal">Yes</button>
                    <button type="button" class="btn btn-default" data-dismiss="modal">No</button>
                </div>
            </div>
        </div>
    </div>
</div>

Step 8: Creating component, service and template for Employee

ts File: app.EmpService.ts

import { Http, Response,RequestOptions,Headers } from '@angular/http';
import { Injectable } from '@angular/core';
import 'rxjs/add/operator/map';
import { Observable } from 'rxjs/observable';
import { Employee } from './../app.models';

@Injectable()
export class EmpService {
    employees: Employee[];
    constructor(private http: Http) {
    }

    GetEmployees(): Observable<Employee[]> {
        return this.http.get("/api/ManageEmployee").map((res: Response) => res.json());
    }
    GetEmployee(empId: any): Observable<Employee> {
        const url = `${'/api/ManageEmployee'}/${empId}`;
        return this.http.get(url).map((res: Response) => res.json());
    }
    AddEmployee(emp: Employee): Observable<Employee[]>{
        let data = JSON.stringify(emp);
        let headers: Headers = new Headers({ "content-type": "application/json" });
        let options: RequestOptions = new RequestOptions({ headers: headers });
       return this.http.post("/api/ManageEmployee/AddEmployee", data, options).map((res: Response) => res.json());
    }
    UpdateEmployee(emp: Employee): Observable<Employee[]> {
        const url = `${'/api/ManageEmployee'}/${emp.EmpId}`;
        let data = JSON.stringify(emp);
        let headers: Headers = new Headers({ "content-type": "application/json" });
        let options: RequestOptions = new RequestOptions({ headers: headers });
        return this.http.put(url, data, options).map((res: Response) => res.json());
    }
    DeleteEmployee(empId: any): Observable<Employee[]> {
        const url = `${'/api/ManageEmployee'}/${empId}`;
        return this.http.delete(url).map((res: Response) => res.json());
    }
}

File Name: emp.component.ts

import { Component, OnInit, Input } from '@angular/core';
import { EmpService } from './app.EmpService';
import { DeptService } from './../Department/app.DeptService';
import { Employee, Department } from './../app.models';

@Component({
    templateUrl: './EmpTemplate.html',
    providers: [EmpService, DeptService]

})
export class EmpComponent implements OnInit {
    employees: Employee[];
    action: string = "Add";
    employee: Employee = new Employee();

    departments: Department[];
    department: Department = new Department();

    constructor(private empService: EmpService, private deptService: DeptService) { }
    ngOnInit() {
        this.GetEmployees();
    }
    Add() {
        this.action = "Add";
        this.employee = new Employee();
        this.GetDepartments();
    }
    GetEmployees() {
        this.empService.GetEmployees().subscribe(emps => this.employees = emps);
    }
    GetDepartments() {
        this.deptService.GetDepartments().subscribe(depts => this.departments = depts);
    }
    GetEmployee(empId: any) {
        this.empService.GetEmployee(empId).subscribe(emp => this.employee = emp);
    }
    AddEmployee() {
        this.empService.AddEmployee(this.employee).subscribe(emps => this.employees = emps);
    }
    EditEmployee(empId: any) {
        this.GetEmployee(empId);
        this.GetDepartments();
        this.action = "Edit";
    }
    UpdateEmployee() {
        this.empService.UpdateEmployee(this.employee).subscribe(emps => this.employees = emps);
    }
    DeleteEmployee(empId: any) {
        this.empService.DeleteEmployee(empId).subscribe(emps => this.employees = emps);
    }
}

File: EmpTemplate.html

<div class="clearfix"> </div>
<div class="container">
    <button class="btn btn-primary" data-toggle="modal" data-target="#myModal" (click)="Add()">Add New</button>
    <div class="clearfix"> </div>
    <table class="table table-striped table-bordered" style="width:50%">
        <thead>
            <tr>
                <th>Employee name</th>
                <th>Employee Salary</th>
               <!-- <th>Department</th>-->
                <th></th>
                <th></th>
            </tr>
        </thead>
        <tbody>
            <tr *ngFor="let emp of employees">
                <td>{{emp.EmpName}}</td>
                <td>{{emp.EmpSalary}}</td>
                <!--<td>{{emp.Department.DeptName}}</td>-->
                <td><button type="button" class="btn btn-info" (click)="EditEmployee(emp.EmpId)" data-toggle="modal" data-target="#myModal">Edit</button> </td>
                <td><button type="button" class="btn btn-danger" (click)="GetEmployee(emp.EmpId)" data-toggle="modal" data-target="#deleteModal">Delete</button> </td>
            </tr>
        </tbody>
    </table>
    <div id="myModal" class="modal fade" role="dialog">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal">×</button>
                    <h4 class="modal-title">Add/Edit Employee</h4>
                </div>
                <div class="modal-body">
                    <form name="addEditForm">
                        <div class="form-group">
                            <label for="empName">Employee Name</label>
                            <input type="text" class="form-control" name="empName" id="empName" [(ngModel)]="employee.EmpName" required />
                        </div>
                        <div class="form-group">
                            <label for="empSal">Employee Salary</label>
                            <input type="text" class="form-control" name="empSal" id="empSal" [(ngModel)]="employee.EmpSalary" required />
                        </div>
                        <div class="form-group">
                            <label for="dept">Department</label>
                            <select name="selectDepartment" class="form-control" id="dept" [(ngModel)]="employee.FKDeptId">
                                <option *ngFor="let dept of departments" value="{{dept.DeptId}}">{{dept.DeptName}}</option>
                            </select>
                        </div>
                        <div class="form-group">
                            <button type="submit" class="btn btn-info" (click)="AddEmployee()" *ngIf="action=='Add'" data-dismiss="modal">Add</button>
                            <button type="submit" class="btn btn-info" (click)="UpdateEmployee()" *ngIf="action=='Edit'" data-dismiss="modal">Update</button>
                            <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                        </div>
                    </form>
                </div>
            </div>
        </div>
    </div>

    <div id="deleteModal" class="modal fade" role="dialog">
        <div class="modal-dialog">

            <!-- Modal content-->
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal">×</button>
                    <h4 class="modal-title">Are you sure want to delete?</h4>
                </div>
                <div class="modal-body">
                    Employee Name: <b>{{employee.EmpName}}</b>
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-danger" (click)="DeleteEmployee(employee.EmpId)" data-dismiss="modal">Yes</button>
                    <button type="button" class="btn btn-default" data-dismiss="modal">No</button>
                </div>
            </div>
        </div>
    </div>
</div>

Step 9: Configuring the application to use Http service in root NgModule

File: app.module.ts

Here default routing is navigated to EmpComponent in app.routing

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { CommonModule } from '@angular/common';
import { AppComponent } from './app.component';  //importing app.component module
import { EmpComponent } from './Employee/emp.component';
import { HttpModule } from '@angular/http';
import { FormsModule } from '@angular/forms';
import { routing } from './app.routing';

@NgModule({
    imports: [BrowserModule, HttpModule, FormsModule,routing],
    declarations: [AppComponent, EmpComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }


File: app.routing.ts
As we are considering this app.routing as root module we have configured routes in forRoot.
import { ModuleWithProviders } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { EmpComponent } from './Employee/emp.component';
import { DeptComponent } from './Department/dept.component';
const routes: Routes = [
    { path: '', redirectTo: 'emp', pathMatch: 'full' },
    { path: 'emp', component: EmpComponent },
    { path: 'dept', loadChildren: './app/EmpDept/Department/dept.module#DeptModule' }
];

export const routing: ModuleWithProviders = RouterModule.forRoot(routes);

Step 10: Now create HTML file and use your component selector

<script>
        System.import('app/EmpDept/main.js').catch(function (err) { console.error(err); });
    </script>
<body>
    <my-app>Loading...</my-app>
</body>

Output: You can perform all the crud operations.

Aslso See link Different types of cursors in SQL server