Web API 2的简单使用

WebAPI project:

 

 UsersViewModel.cs

public class UsersViewModel
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string PWD { get; set; }
}

UsersController.cs

public class UsersController : ApiController
{
　　 // api/users
    public IHttpActionResult GetAllUsers()
    {
        IList<UsersViewModel> users = null;

        using (var ctx = new masterEntities())
        {
            users = ctx.UsersTables.Select(s => new UsersViewModel()
            {
                Id = s.Id,
                Name = s.Name,
                PWD = s.PWD
            }).ToList<UsersViewModel>();
        }

        if (!users.Any())
        {
            return NotFound();
        }

        return Ok(users);
    }
    // api/users?id=1
    public IHttpActionResult GetUserById(int id)
    {
        IList<UsersViewModel> users = null;

        using (var ctx = new masterEntities())
        {
            users = ctx.UsersTables.Where(i => i.Id == id).Select(s => new UsersViewModel()
            {
                Id = s.Id,
                Name = s.Name,
                PWD = s.PWD
            }).ToList<UsersViewModel>();
        }

        if (!users.Any())
        {
            return NotFound();
        }

        return Ok(users);
    }

    public IHttpActionResult GetUserByName(string name)
    {
        IList<UsersViewModel> users = null;

        using (var ctx = new masterEntities())
        {
            users = ctx.UsersTables.Where(i => i.Name == name).Select(s => new UsersViewModel()
            {
                Id = s.Id,
                Name = s.Name,
                PWD = s.PWD
            }).ToList<UsersViewModel>();
        }

        if (!users.Any())
        {
            return NotFound();
        }

        return Ok(users);
    }

    public IHttpActionResult GetUserByPWD(string pwd)
    {
        IList<UsersViewModel> users = null;

        using (var ctx = new masterEntities())
        {
            users = ctx.UsersTables.Where(i => i.PWD == pwd).Select(s => new UsersViewModel()
            {
                Id = s.Id,
                Name = s.Name,
                PWD = s.PWD
            }).ToList<UsersViewModel>();
        }

        if (!users.Any())
        {
            return NotFound();
        }

        return Ok(users);
    }

    public IHttpActionResult PostNewUser(UsersViewModel user)
    {
        if (!ModelState.IsValid)
            return BadRequest("Invalid data.");

        using (var ctx = new masterEntities())
        {
            ctx.UsersTables.Add(new UsersTable()
            {
                Id = user.Id,
                Name = user.Name,
                PWD = user.PWD
            });

            ctx.SaveChanges();
        }

        return Ok();
    }

    public IHttpActionResult Put(UsersViewModel user)
    {
        if (!ModelState.IsValid)
            return BadRequest("Not a valid model.");

        using(var ctx = new masterEntities())
        {
            var existuser = ctx.UsersTables.Where(u => u.Id == user.Id)
                                            .FirstOrDefault<UsersTable>();

            if(existuser != null)
            {
                existuser.Name = "NewName";

                ctx.SaveChanges();
            }
            else
            {
                return NotFound();
            }
        }

        return Ok();
    }

    public IHttpActionResult Delete(int id)
    {
        if (!ModelState.IsValid)
            return BadRequest("Not a valid model.");

        if (id <= 0)
            return BadRequest("Invalid id.");

        using(var ctx = new masterEntities())
        {
            var usertodelete = ctx.UsersTables.Where(u => u.Id == id)
                                                .FirstOrDefault();

            if(usertodelete != null)
            {
                ctx.Entry(usertodelete).State = System.Data.Entity.EntityState.Deleted;
                ctx.SaveChanges();
            }
            else
            {
                return NotFound();
            }
        }

        return Ok();
    }
}

---

在另一个项目中调用API，创建相应的Service类

UserService.cs

class UserService
{
    string url = @"https://localhost:44378";

    static UserService instance;
    public static UserService Instance
    {
        get { return instance ?? (instance = new UserService()); }
    }

    public IEnumerable<User> GetAllUsers()
    {
        IEnumerable<User> users = null;

        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri("https://localhost:44357/api/");
            var responseTask = client.GetAsync("users");
            try
            {
                responseTask.Wait();
            }
            catch
            {
                MessageBox.Show("connection failed");
                return Enumerable.Empty<User>();
            }

            var result = responseTask.Result;
            if (result.IsSuccessStatusCode)
            {
                var readTask = result.Content.ReadAsStringAsync();
                readTask.Wait();

                users = JsonConvert.DeserializeObject<List<User>>(readTask.Result);
            }
            else
            {
                users = Enumerable.Empty<User>();
            }
        }
        return users;
    }

    public void PostNewUsers(User user)
    {
        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri("https://localhost:44357/api/");

            string json = JsonConvert.SerializeObject(user);
            StringContent httpContent = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
            var postTask = client.PostAsync("users", httpContent);
            try
            {
                postTask.Wait();
            }
            catch
            {
                MessageBox.Show("connection failed");
            }

            var result = postTask.Result;
            if (result.IsSuccessStatusCode)
            {
                MessageBox.Show("User added");
            }
        }
    }

    public void UpdateUser(User user)
    {
        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri("https://localhost:44357/api/");

            string json = JsonConvert.SerializeObject(user);
            StringContent httpContent = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
            var putTask = client.PutAsync($"users?id={user.Id}", httpContent);

            try
            {
                putTask.Wait();
            }
            catch
            {
                MessageBox.Show("connection failed");
            }

            var result = putTask.Result;
            if (result.IsSuccessStatusCode)
            {
                MessageBox.Show("User updated");
            }
        }
    }

    public void DeleteUser(User user)
    {
        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri("https://localhost:44357/api/");

            var deleteTask = client.DeleteAsync($"users?id={user.Id}");
            try
            {
                deleteTask.Wait();
            }
            catch
            {
                MessageBox.Show("connection failed");
            }

            var result = deleteTask.Result;
            if (result.IsSuccessStatusCode)
            {
            }
        }
    }
}

通过Instance调用

void GetUsers()
{
    Users.Clear();
    UserService.Instance.GetAllUsers().ToList().ForEach(u => Users.Add(u));
}

void AddNewUser()
{
    User newuser = new User { Id = 999, Name = "King", PWD = "@1" };
    UserService.Instance.PostNewUsers(newuser);
}

void UpdateUser()
{
    User newuser = new User { Id = 999, Name = "Test", PWD = "123" };
    UserService.Instance.UpdateUser(newuser);
}

void DeleteUser()
{
    UserService.Instance.DeleteUser(SelectedUser);
    GetUsers();
}

 参考资料：ASP.NET Web API Tutorials (tutorialsteacher.com)