Recently I have faced with an issue in mvc. My problem is about how increment a value of field which is unique,primary and int. For example , I have a customerCode as int and I want to increment a value of that after saving new customer . I get that mvc first check id and if its equal to zero ,then increment it to max+1. But the issue is here: if I want to increment it like Max+4, how can I handle it?
this is my code:
public ActionResult Save(Customers customer)
{
if (!ModelState.IsValid)
{
var _Customer = new CreatnewCustomerViewModel()
{
Customer = customer,
membershiptype = _context.membershiptype.ToList()
};
return View("CustomerForm", _Customer);
}
if (customer.CustomerID==0)
{
//int id = _context.customers.Max(m => m.CustomerID);
//customer.CustomerID = id + 1;
_context.customers.Add(customer);
}
else
{
var CustomerIndb = _context.customers.Single(c => c.CustomerID == customer.CustomerID);
{
CustomerIndb.Name = customer.Name;
CustomerIndb.birthday = customer.birthday;
CustomerIndb.IsSubscribedToNewsletter = customer.IsSubscribedToNewsletter;
// CustomerIndb.MembershipType = customer.MembershipTypeID;
CustomerIndb.MembershipTypeID = customer.MembershipTypeID;
}
}
_context.SaveChanges();
return RedirectToAction("index", "Customer");
}
Write your Customers model class as follows:
public class Customers
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int CustomerID { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int CustomerCode { get; set; }
public string Name { get; set; }
// Other properties
}
Now generate a new migration and update the database accordingly!
Now if you want to set Identity Increment more than 1, then go to the database with SQL Server Management Studio, open the the Customers table. Right click on CustomerCode column and then select properties. Now set the Identity Increment value (default is 1) to your desired value.
you can easily solve that problem with the help of DatabaseGeneratedOption.Identity and Sql() method in the Up() .
If you new to both of above concepts , Here is the links with clear instructions
https://forums.asp.net/t/2062551.aspx?Entity+Framework+How+to+set+a+start+value+for+an+Auto+Incremented+Column+
Addtional:
How to set initial value for auto incremented property (DatabaseGeneratedOption.Identity)
Hope it will help to get rid of the problem, let me know your status.
Thanks
Related
Store update, insert, or delete statement affected an unexpected
number of rows (0). Entities may have been modified or deleted since
entities were loaded. See
http://go.microsoft.com/fwlink/?LinkId=472540 for information on
understanding and handling optimistic concurrency exceptions.
In the following function (MVC action):
// POST: api/Day
public void Post(int bed, DateTime date, float operatingTime)
{
Day currentDay = new Day()
{
Date = date,
BedId = bed,
OperatingTime = operatingTime
};
db.Entry(currentDay).State = EntityState.Modified;
db.SaveChanges();
}
The Day class looks like this:
using System;
using System.Collections.Generic;
public partial class Day
{
public int Id { get; set; }
public float OperatingTime { get; set; }
public System.DateTime Date { get; set; }
public int BedId { get; set; }
public virtual Bed Bed { get; set; }
}
In the action, the particular Day may or may not already exist. I intend for a new Day to be created if it doesn't exist or an existing one be updated. The Day table has Date and BedId as a composite primary key.
I also tried "attaching" the entity first.
Am I mistaken in assuming that my code will create a new entry if one with a matching (composite) key doesn't exist?
Thanks!
Your logic will not create a new entry if one is not found. EntityState.Modified will create an UPDATE statement. If you want to insert if not found, then you'll need to query the db first. I don't like the idea of doing an insert OR an update inside a method called Post, but if you prefer that, you could try something like:
// POST: api/Day
public void Post(int bed, DateTime date, float operatingTime)
{
Day currentDay = new Day()
{
Date = date,
BedId = bed,
OperatingTime = operatingTime
};
var dayExists = db.Day.FirstOrDefault(d => d.Date == date && d.BedId == bed);
if (dayExists != null)
{
// you have a record, so update it
db.Entry(currentDay).State = EntityState.Modified;
}
else
{
// no record found, insert one
db.Entry(currentDay).State = EntityState.Added;
}
db.SaveChanges();
}
I searched hours and hours for this without any luck. I'm trying to create a lambda expression to fetch data from two tables Schedule and Request. But i'm outputting a bool here. How can i do a proper left outer join to fix this?
this is the best i could come up with
ViewBag.RequestList = db.Requests
.Include(r => r.Department)
.Select(r => db.Schedules.Any(s => s.RequestId == r.RequestId));
but its a bool not a list.
Assume my table models are as follows
public class Request{
public virtual int RequestId { get; set; }
public virtual string Remarks { get; set; }
}
public class Schedule{
public virtual int ScheduleId{ get; set; }
public virtual string Name{ get; set; }
public virtual Request Request { get; set; }
}
I'm trying to see if each and every request has one or more schedules associated with it or not. so if i could attach schedule object to request and output it as a list then thats all i need.
But I want to do it using LINQ and lambda expressions and I've seen queries as below;
var leftList = (from emp in db.Requests
join d in db.Schedules
on emp.RequestId equals d.RequestId into output
from j in output.DefaultIfEmpty()
select new { RequestId = emp.RequestId,
name = emp.Department.Name,
route = emp.Route.Name });
But that's not what i want, because i have to specify every field i need in new { RequestId = emp.RequestId, name = emp.Department.Name, route = emp.Route.Name }
Thanks a lot!
just list what you want like this:
var leftList = from emp in db.Requests
join d in db.Schedules
on emp.RequestId equals d.RequestId into output
from j in output.DefaultIfEmpty()
select new
{
RequestId = emp.RequestId,
name = emp.Department.Name,
route = emp.Route.Name,
ScheduleId=j==null?0:j.ScheduleId,
SName=j==null?""j.Name,
};
Let's say I have two models:
public class User
{
[Key]
public int UserId { get; set; }
public string Name { get; set; }
}
and
public class Friend
{
[Key]
public int FriendId { get; set; }
public User A { get; set; }
public User B { get; set; }
}
Let's say I only have 2 users in my database (ids: 1 (Jon) and 2 (Sam)). Now I insert into table friend like this:
db.Friends.Add(new Friend()
{
A = db.Users.Find(1),
B = db.Users.Where(u => u.UserId == 2).First()
});
db.SaveChanges();
Suddenly, I find a user (3, Sam) in a table user. What is the reasoning behind this? Not completely sure if relevant or not, but note that even if I make A and B fields virtual, nothing changes.
UPDATE
Finally found how to reproduce my problem. Apparently the problem isn't exactly the same as I described.
User a, b;
using (var db = new DbConnection())
{
a = db.Users.First(u => u.UserId == 1);
b = db.Users.First(u => u.UserId == 2);
}
using (var db = new DbConnection())
{
db.Friends.Add(new Friend()
{
A = a,
B = b
});
db.SaveChanges();
}
Now users will have 4 users. Does it mean that if I step out of transaction, I can no longer access the entities as if they were exactly the same items in the current transaction? Or maybe there is a way to make the program know that I am referring to the same item (because the ID is the same)?
Honestly tried the same steps as you described and everything work well.. Anyway my steps
Created a db context class derived from `DbContext'
public class EFContext : DbContext
{
public DbSet<Friend> Friends { get; set; }
public DbSet<User> Users { get; set; }
public EFContext(string connectionString)
: base(connectionString)
{
}
}
I use MSQL2008 Express with win auth so I created the Users table
using (var db = new EFContext(#"Data Source=yourMachineName\SQLEXPRESS2008;Initial Catalog=DBName;Integrated Security=True;MultipleActiveResultSets=True"))
{
db.Users.Add(new User()
{
UserId = 1,
Name = "John"
});
db.Users.Add(new User()
{
UserId = 2,
Name = "Sam"
});
db.SaveChanges();
}
I checked my db and found 2 records
After I created the Friends table
using(var db = new EFContext(#"Data Source=yourMachineName\SQLEXPRESS2008;Initial Catalog=DBName;Integrated Security=True;MultipleActiveResultSets=True"))
{
db.Friends.Add(new Friend()
{
A = db.Users.Find(1),
B = db.Users.Where(u => u.UserId == 2).First()
});
db.SaveChanges();
}
Again I got 1 record in the Friends table with columns FriendId=1, A_UserId=1, B_UserId=2.
I checked the Users table and I still have 2 records.
If I were you I would try my code in a separate app. If it works then please post here all steps which led you to this problem.
I'm using jqGrid to display some data on a page. Within the controller action, we're using an anonymous object to represent the data that the jqGrid needs. My question is, is there a way we can create a strongly typed object to represent the jqGrid data that we are sending with Json()?
Main reason for this is so that we can do unit testing with the objects that are being sent to it.
Thanks!
EDIT:
[AcceptVerbs(HttpVerbs.Post)]
public JsonResult GridData(FormCollection form, string alias, string location, string state)
{
int pageSize = Convert.ToInt32(form["rows"]);
int pageIndex = Convert.ToInt32(form["page"]) - 1;
var deviceList = this._device.GetList(CreateFilter(location,alias,state),this._securityCache.GetSecurityContext(),pageSize,pageIndex);
int totalResults = deviceList.TotalRecords;
int totalPages = (int)Math.Ceiling((float)totalResults / (float)pageSize);
var jsonData = new {
total = totalPages,
page = pageIndex + 1,
records = totalResults,
rows = (from device in deviceList.Data
select new {i = device.Alias,cell = new string[]{device.Alias,device.Location,device.RatePlan,device.State,device.DateCreated.ToString()}}).ToArray()
};
return Json(jsonData);
This above here works, but we can't unit test the data that is being passed into the Json() method.
var newJsonData = new JsonJQGridReturnData();
newJsonData.total = totalPages;
newJsonData.page = pageIndex + 1;
newJsonData.records = totalResults;
List<JsonJQGridRow> list = new List<JsonJQGridRow>();
foreach (var device in deviceList.Data)
{
list.Add(new JsonJQGridRow(device.Alias, new string[] { device.Alias, device.Location, device.RatePlan, device.State, device.DateCreated.ToString() }));
}
newJsonData.rows = list.ToArray();
_cookieHelper.SaveCookie("DeviceListIndex", this._securityCache.GetSecurityContext().UserID.ToString(), COOKIE_PAGE_SIZE_KEY, pageSize.ToString());
return Json(newJsonData);
}
Here is my poor attempt at trying to wrap these into strongly typed objects. Unfortunately, running this gives me a "u is undefined" in the jqGrid file. I suspect that this is because the json being passed in is not correctly formatted. Here are the classes....
[DataContract]
public class JsonJQGridReturnData
{
[DataMember]
public int total { get; set; }
[DataMember]
public int page { get; set; }
[DataMember]
public int records { get; set; }
[DataMember]
public JsonJQGridRow[] rows { get; set; }
}
[DataContract]
public class JsonJQGridRow
{
public JsonJQGridRow(string i, string[] columns)
{
this.i = i;
this.cells = columns;
}
[DataMember]
public string i { get; set; }
[DataMember]
public string[] cells { get; set; }
}
If I understand your question you can use Generics to do this:
Model:
// represents one row in the JQGrid
class Customer
{
public string firstname { get; set; }
public string lastname { get; set; }
}
JQGrid class:
class JQGridData<TModel>
{
// add in whatever other properties you want for JQGrid
public int responseTime {get; set; };
public List<TModel> rows = new List<TModel>();
}
Controller Action :
public JsonResult GridData(int page)
{
var gridData = new JQGridData<Customer>();
// Populate your data here, this is just an example:
gridData.rows.Add(new Customer()
{
firstname = "fred", lastname = "pharkas"
});
// return the result
return Json(gridData, JsonRequestBehavior.AllowGet);
}
Result:
{
responseTime: 0
rows: [
{
firstname: "fred"
lastname: "pharkas"
}
]
}
Is that what you were asking?
David,
Here's the kinda thing i use in an app i'm working on at the moment for this type of thing. I know it doesn't provide a strongly typed object as such, but the 'list' could be a part of the model that is then sent ToArray() at the end of the piece.
public JsonResult GridData(int id)
{
// get our messages based on id
var bookingmessagesList = _repository.Find(x => x.ID == id);
var list = new ArrayList();
foreach (var bookingmessage in bookingmessagesList) //populate data containers with read data
{
list.Add(new
{
bookingmessage.ClassRowVersionDate,
bookingmessage.ID,
bookingmessage.BookingID,
bookingmessage.AssignedFrom,
bookingmessage.AssignedTo,
bookingmessage.AssignedDate,
bookingmessage.CompletedDate,
bookingmessage.MessageType,
bookingmessage.Notes
});
}
int totalOjectCount = list.Count;
return Json(new { dataitems = list.ToArray(), totalItems = totalOjectCount });
}
hope it gives you some ideas.. Will be interested to see the suggestions made.
Here's a quick take on a strongly-typed JQGridResult.
public class JQGridResult<T> : JsonResult where T : class
{
public T Model
{
get { return (T)this.Data; }
set { this.Data = value; }
}
}
Used as...
return new JQGridResult<JsonModel> {
Model = new GridModel { ... initialize model here ... }
});
where GridModel is basically a container class holding the strongly typed properties for the grid.
I feel really silly. I had a misspelling in the GridRow that was causing jqGrid to blow up. After I fixed that, I was able to get the jqGrid to work with my strongly typed object...
Now in my unit tests, I can just do...
var result = controllerToTest.GridData(form, null, null, null) as JsonResult;
var data = result.Data as JsonJQGridReturnData;
and now I can access the fields :D
I would like to use Linq and strongly typed views in the right way. at the moment I do the following:
Make a Model to verify agianst:
public class Menu
{
public int Id { get; private set; }
public string Text { get; private set; }
public string Action { get; private set; }
public string Controller { get; private set; }
public string Parameter { get; private set; }
public string Langue { get; private set; }
public Menu(int id, string controller, string action, string parameter, string text)
{
Id = id;
Controller = controller;
Action = action;
Text = text;
Parameter = parameter;
}
Use Linq to get the data from the database into the model:
public static List<Menu> GetTabListForMenu(string langue)
{
Page_dbEntities entity = new Page_dbEntities();
var tabList = (from ml in entity.wpmenulangue
where ml.Langue == langue
from m in entity.wpmenu
where ml.Menu == m.Id
from l in entity.wplangue
where ml.Langue == l.Langue
from p in entity.wppage
where p.Id == m.Page
select new { m.Id, p.Controller, p.Action, p.Parameter, ml.Text}).ToList();
List<Menu> menu = new List<Menu>();
foreach (var item in tabList)
{
menu.Add(new Menu(item.Id, item.Controller, item.Action, item.Parameter, item.Text));
}
return menu;
}
I am pretty convinced that this is not the optimal way to do this and have 2 questions:
When I get the data from the database I first use a var and then have to move it to the object with a foreach. this seems like a waste of both my time and less effeicent then getting it with sql.
I have been told that I can just verify up agianst the entitymodel. Even if i use multiple entities in a view. is this true? (the one telling me this wes not able to get it to work and I have not been able to find anything about it online).
I will try to look back on this post in the next couple of hours, but might have to wait 24 hours.
public static List<Menu> GetTabListForMenu(string langue)
{
Page_dbEntities entity = new Page_dbEntities();
return (from ml in entity.wpmenulangue
where ml.Langue == langue
from m in entity.wpmenu
where ml.Menu == m.Id
from l in entity.wplangue
where ml.Langue == l.Langue
from p in entity.wppage
where p.Id == m.Page
select new Menu(m.Id, p.Controller, p.Action, p.Parameter, ml.Text)
).ToList();
}
As for the validation is concerned you shouldn't use multiple entities in the view. You should use a single entity which is called ViewModel. This ViewModel is a class that represents the data on the view. If you are using DataAnnotations for validation you could decorate this view model properties with attributes that indicate how to be validated.