在 MVC 中实现 CRUD

Question

我还是 MVC 的新手。现在在我的控制器中，我想执行基本的 CRUD，例如创建、编辑、详细信息。

我使用MySql作为数据库。

当我在调试模式下运行程序时，它没有显示错误。但是，在创建页面中，当我单击“提交”按钮时，输入的新数据不会在索引中更新。我想知道为什么在这里需要帮助。

你们能告诉我在创建和编辑中哪里做错了吗？提前致谢。

控制器：

    //GET UserActivity/Details/5
    public ActionResult Details(int id)
    {
        string sqlQuery = @"
          SELECT ua.Id
            ,ua.CreatedBy
            ,ua.CreatedOn
            ,ua.ModifiedBy
            ,ua.ModifiedOn
            ,ua.ContactId
            ,ua.EntityName
            ,ua.EntityId
            ,ua.StatusCode
            ,ua.StateCode
            ,ua.ActivityType
            ,ua.ActivityStatus
            ,ua.DueDate
            ,ua.ActualEndDate
            ,ua.MasqueradeOn
            ,ua.MasqueradeBy 

            FROM UserActivity ua
            INNER JOIN Contact c ON c.Id = ua.ContactId
            WHERE ua.id = @UserActivityId
        ";

        UserActivityModels userActivity = null;

        using (IDbConnection db = new MySqlConnection
            (ConfigurationManager.ConnectionStrings["CRMPORTALSQLCONN"].
            ConnectionString))
        {
            userActivity = (UserActivityModels)db.Query<UserActivityModels>(sqlQuery
               , new
               {
                   @UserActivityId = id
               }).FirstOrDefault();

        }
        return View(userActivity);
    }

    /* // POST: /UserActivity/Details
    [HttpPost]
    public ActionResult Details(FormCollection collection)
    {
        try
        {
            // TODO: Add insert logic here

            return RedirectToAction("Details");
        }
        catch
        {
            return View();
        }
    }
    */


    //----------------------------------------------------------------------------------------------------//


    //GET /UserActivity/Create
    public ActionResult Create()
    {

        return View();
    }


    //
    // POST: /UserActivity/Create
    [HttpPost]
    public ActionResult Create(FormCollection collection)
    {
        try
        {
            /*
            if (ModelState.IsValid)
            {
                userActivity.Add(useractivity);
                */
            UserActivityModels useractivity = new UserActivityModels();

            int Id = Convert.ToInt32(collection["Id"]);
            int CreatedBy = Convert.ToInt32(collection["Created By"]);
            DateTime CreatedOn = Convert.ToDateTime(collection["Created On"]);
            int ModifiedBy = Convert.ToInt32(collection["Modified By"]);
            DateTime ModifiedOn = Convert.ToDateTime(collection["Modified On"]);
            string ContactId = collection["Contact Id"];
            int StatusCode = Convert.ToInt32(collection["Status Code"]);
            int StateCode = Convert.ToInt32(collection["State Code"]);
            string EntityName = collection["Entity Name"];
            int EntityId = Convert.ToInt32(collection["Entity Id"]);
            DateTime DueDate = Convert.ToDateTime(collection["Due Date"]);
            DateTime ActualEndDate = Convert.ToDateTime(collection["Actual EndDate"]);
            DateTime MasqueradeOn = Convert.ToDateTime(collection["Masquerade On"]);
            DateTime MasqueradeBy = Convert.ToDateTime(collection["Masquerade By"]);
            string ContactName = collection["Contact Name"];

            userActivity.Add(useractivity);


            return RedirectToAction("Index");

        }

        catch
        {
            return View();
        }

    }




    //---------------------------------------------------------------------//



    // GET: /UserActivity/Edit/5
    public ActionResult Edit(int id)
    {
        //ConfigurationManager.ConnectionStrings["CRMPORTALSQLCONN"].ConnectionString);
        string query = @"
          SELECT ua.Id
            ,ua.CreatedBy
            ,ua.CreatedOn
            ,ua.ModifiedBy
            ,ua.ModifiedOn
            ,ua.ContactId
            ,ua.EntityName
            ,ua.EntityId
            ,ua.StatusCode
            ,ua.StateCode
            ,ua.ActivityType
            ,ua.ActivityStatus
            ,ua.DueDate
            ,ua.ActualEndDate
            ,ua.MasqueradeOn
            ,ua.MasqueradeBy 
    ,concat(c.FirstName, ' ', c.LastName) AS ContactName
            FROM UserActivity ua
            INNER JOIN Contact c ON c.Id = ua.ContactId
            WHERE ua.id = @userActivityId

        ";

        UserActivityModels userActivity = null;

        using (IDbConnection db = new MySqlConnection(ConfigurationManager.
            ConnectionStrings["CRMPORTALSQLCONN"].ConnectionString))
        {
            // userActivity = (UserActivityModels)db.Query<UserActivityModels>(query);


            userActivity = db.Query<UserActivityModels>(query
                , new
                {
                    @UserActivityId = id
                }).FirstOrDefault();
        }
        return View(userActivity);
    }

    // POST: /UserActivity/Edit/
    [HttpPost]
    public ActionResult Edit()
    {
        if (ModelState.IsValid)
        {

            // TODO: Add update logic here

            return RedirectToAction("Index");
        }
        return View(userActivity);

    }


    //------------------------------------------------------------------------//


    // GET: /UserActivity/Delete/
    public ActionResult Delete(int? id)
    {
        return View();
    }

    // POST: /SavedCar/Delete/5
    [HttpPost]
    public ActionResult Delete(int id, FormCollection collection)
    {


        try
        {
            // TODO: Add delete logic here

            return RedirectToAction("Index");
        }
        catch
        {
            return View();
        }
    }
}

用户活动模型：

 public class UserActivityModels
{
    [Display(Name = "Id")]
    public int Id { get; set; }

    [Display(Name = "Created By")]
    public int CreatedBy { get; set; }

    [Display(Name = "Created On")]
    [DataType(DataType.DateTime)]
    public DateTime CreatedOn { get; set; }

    [Display(Name = "Modified By")]
    public int ModifiedBy { get; set; }

    [Display(Name = "Modified On")]
    [DataType(DataType.DateTime)]   
    public DateTime ModifiedOn { get; set; }

    [Display(Name = "Contact Id")]
    public string ContactId { get; set; }

    [Display(Name = "Entity Name")]
    public string EntityName { get; set; }

    [Display(Name = "Entity Id")]
    public int EntityId { get; set; }

    [Display(Name = "Status Code")]
    public int StatusCode { get; set; }

    [Display(Name = "State Code")]
    public int StateCode { get; set; }

    [Display(Name = "Activity Type")]
    public int ActivityType { get; set; }

    [Display(Name = "Activity Status")]
    public string ActivityStatus { get; set; }

    [Display(Name = "DueDate")]
    [DataType(DataType.DateTime)]
    public DateTime DueDate { get; set; }

    [Display(Name = "Actual EndDate")]
    [DataType(DataType.DateTime)]
    public DateTime ActualEndDate { get; set; }

    [Display(Name = "Masquerade On")]
    [DataType(DataType.DateTime)]
    public DateTime MasqueradeOn { get; set; }

    [Display(Name = "Masquerade By")]
    public int MasqueradeBy { get; set; }

    [Display(Name = "Contact Name")]
    public string ContactName { get; set; }

Answer 1

在 Create Post Controller 你有

int Id = Convert.ToInt32(collection["Id"]);

如果 Id 是自增的，你只需输入 int Id=0 或者你不需要提供它。如果您自己提供Id，它可能会重复并且无法完成插入。 关于编辑视图，隐藏 Id 很重要，这样您才能真正更新正确的 Id。请检查以下内容： - 你的mysql表结构 - 在创建视图中删除 ID 字段 - 在编辑视图中添加隐藏的 ID 字段 - 检查你的控制器。

Answer 2

在您的更新方法中，您应该获取模型然后将其提供给数据库。

这里有几个简单的例子：

[Post]
public ActionResult Add(User u) {
     // Need to define 'db' as a Data connection
     db.Users.Add(u);
     db.SubmitChanges();
     return View(u);
}


[Post]
public ActionResult Update(User u) {
     // Need to define 'db' as a Data connection
     var updatedUser = db.Users.Where(k=>k.Id == u.Id).FirstOrDefault();
     updatedUser = u;
     db.SubmitChanges();
     return View(updatedUser);
}

Answer 3

仅将元素添加到 userActivity 不会更新 数据库。因此，每次您尝试显示页面时，它都会重新创建一个 新控制器 和一个new userActivity。要解决这个问题，在Create Action 中，您必须将新的用户活动添加到数据库中，而不是添加到userActivity。