this is mine model
public class QMSRejection
{
public string Date { get; set; }
public string Grade { get; set; }
public string Resd { get; set; }
public string Remarks { get; set; }
}
this is mine firstpage.xaml.cs from where I am passing a data to another page !
List<QMSRejection> DataToSave = new List<QMSRejection>();
var rej = new QMSRejection();
rej.Date = DateTime.Now.ToShortDateString();
rej.Grade = GradeID;
rej.Resd = ResdId;
DataToSave.Add(rej);
await Navigation.PushAsync(new Rejection2ndForm(DataToSave));
now on the second page I am receiving it, data is coming everything working fine !
public partial class Page2 : ContentPage
{
List<QMSRejection> DataToSave = new List<QMSRejection>();
public Rejection2ndForm(List<QMSRejection> models)
{
InitializeComponent ();
DataToSave = models;
}
}
var rej = new QMSRejection();
rej.Remarks = ent3.Text.ToString();
DataToSave.add(rej);
I have a fields Remarks which I am trying to add to existing data coming from page 1.But these lines are creating another IEnumerable in the datatoSave List and remarks field not getting added to previous data ! What should I do in place of these lines to do ?
As I have to add remarks field through page2.xaml.cs !
this creates a new QMSRejection object and adds it to your list
var rej = new QMSRejection();
rej.Remarks = ent3.Text.ToString();
DataToSave.add(rej);
if you instead want to modify an existing QMSRejection object
// [0] means the first object in the list
DataToSave[0].Remarks = ent3.Text.ToString();
Related
How to solve one to many relational issue in asp.net?
I have Topic which contain many playlists.
My code:
public class Topic
{
public int Id { get; set; }
public String Name { get; set; }
public String Image { get; set; }
---> public virtual List<Playlist> Playlist { get; set; }
}
and
public class Playlist
{
public int Id { get; set; }
public String Title { get; set; }
public int TopicId { get; set; }
---> public virtual Topic Topic { get; set; }
}
My controller function
[Route("data/binding/search")]
public JsonResult Search()
{
var search = Request["term"];
var result= from m in _context.Topics where m.Name.Contains(search) select m;
return Json(result, JsonRequestBehavior.AllowGet);
}
When I debug my code I will see an infinite data because Topics will call playlist then playlist will call Topics , again the last called Topic will recall playlist and etc ... !
In general when I just use this relation to print my data in view I got no error and ASP.NET MVC 5 handle the problem .
The problem happens when I tried to print the data as Json I got
Is there any way to prevent an infinite data loop in JSON? I only need the first time of data without call of reference again and again
You are getting the error because your entity classes has circular property references.
To resolve the issue, you should do a projection in your LINQ query to get only the data needed (Topic entity data).
Here is how you project it to an anonymous object with Id, Name and Image properties.
public JsonResult Search(string term)
{
var result = _context.Topics
.Where(a => a.Name.Contains(term))
.Select(x => new
{
Id = x.Id,
Name = x.Name,
Image = x.Image
});
return Json(result, JsonRequestBehavior.AllowGet);
}
If you have a view model to represent the Topic entity data, you can use that in the projection part instead of the anonymous object
public class TopicVm
{
public int Id { set;get;}
public string Name { set;get;}
public string Image { set;get;}
}
public JsonResult Search(string term)
{
var result = _context.Topics
.Where(a => a.Name.Contains(term))
.Select(x => new TopicVm
{
Id = x.Id,
Name = x.Name,
Image = x.Image
});
return Json(result, JsonRequestBehavior.AllowGet);
}
If you want to include the Playlist property data as well, you can do that in your projection part.
public JsonResult Search(string term)
{
var result = _context.Topics
.Where(a => a.Name.Contains(term))
.Select(x => new
{
Id = x.Id,
Name = x.Name,
Image = x.Image,
Playlist = x.Playlist
.Select(p=>new
{
Id = p.Id,
Title = p.Title
})
});
return Json(result, JsonRequestBehavior.AllowGet);
}
In my application i will have dynamic rss feed url saved by users. so i want to know that how can i read that xml which will be returned by rss feed. what will be the structure of that xml ? I have reviewed some feed url and i noticed that most of them have title and description tags but i am not sure to this. if i get these two tags then i will parse xml but if they are not always available then how can i parse xml in that case.
these two contains title and description tag
http://rss.news.yahoo.com/rss/entertainment
http://xml.weather.yahoo.com/forecastrss?p=USCA1116
At first you need to read a XML file for that I recommend you to use XPath or Linq to XML, and as you already said there are three main elements that make up a feed; "title", "link" and "description".
Not a very long time ago I wrote a code to do that, I hope this works for you.
I created this two entities.
public class RssFeed
{
public string Title { get; set; }
public string Link { get; set; }
public string Description { get; set; }
public string PubDate { get; set; }
public string Language { get; set; }
public ObservableCollection<RssItem> RssItems { get; set; }
}
public class RssItem
{
public string Title { get; set; }
public string Description { get; set; }
public string Link { get; set; }
}
Then on this method I read every element from the XML file by using Linq to XML
private static void ReadFeeds()
{
string uri = #"http://news.yahoo.com/rss/entertainment";
WebClient client = new WebClient();
client.DownloadStringAsync(new Uri(uri, UriKind.Absolute));
client.DownloadStringCompleted += (s, a) =>
{
if (a.Error == null && !a.Cancelled)
{
var rssReader = XDocument.Parse(a.Result);
var feed = (from rssFeed in rssReader.Descendants("channel")
select new RssFeed()
{
Title = null != rssFeed.Descendants("title").FirstOrDefault() ?
rssFeed.Descendants("title").First().Value : string.Empty,
Link = null != rssFeed.Descendants("link").FirstOrDefault() ?
rssFeed.Descendants("link").First().Value : string.Empty,
Description = null != rssFeed.Descendants("description").FirstOrDefault() ?
rssFeed.Descendants("description").First().Value : string.Empty,
PubDate = null != rssFeed.Descendants("pubDate").FirstOrDefault() ?
rssFeed.Descendants("pubDate").First().Value : string.Empty,
Language = null != rssFeed.Descendants("language").FirstOrDefault() ?
rssFeed.Descendants("language").First().Value : string.Empty
}).Single();
var rssFeeds = (from rssItems in rssReader.Descendants("item")
select new RssItem()
{
Title = null != rssItems.Descendants("title").FirstOrDefault() ?
rssItems.Descendants("title").First().Value : string.Empty,
Link = null != rssItems.Descendants("link").FirstOrDefault() ?
rssItems.Descendants("link").First().Value : string.Empty,
Description = null != rssItems.Descendants("description").FirstOrDefault() ?
rssItems.Descendants("description").First().Value : string.Empty,
}).ToList();
feed.RssItems = new ObservableCollection<RssItem>(rssFeeds);
}
};
}
And finally you have your feed to be displayed wherever you want.
If I had a class defined with this attributes
public class GestionesDataSet
{
public DateTime GestionInicio { get; set; }
public DateTime GestionFin { get; set; }
public Nullable<DateTime> LlamadaInicio { get; set; }
public Nullable<DateTime> LlamadaFin { get; set; }
public string Login { get; set; }
public string Tipificacion { get; set; }
public List<CamposGestion> campoValor { get; set; }
}
And the class called CamposGestion is defined like this
public class CamposGestion
{
public string Nombre { get; set; }
public string Valor { get; set; }
}
How can I Defined a report where I can use the field that refers to the list of the other elements?
I tried to used one dataset where I can set this linq as object data source
var gestiones = (from G in db.Gestion
where
G.IDTipificacion == idTipificacion
&& (from T in db.Tipificacion where T.IdTipificacion == G.IDTipificacion select T.Servicio.IDServicio).AsEnumerable().Contains(idServicio)
select G).AsEnumerable().Select(xx => new GestionesDataSet()
{
GestionInicio = xx.HoraInicio,
GestionFin = xx.HoraFin,
#Tipificacion = ((from T in db.Tipificacion select T).Where(x => x.IdTipificacion == xx.IDTipificacion).Count() > 0 ?
(from T in db.Tipificacion where T.IdTipificacion == xx.IDTipificacion select T.Nombre).FirstOrDefault() : ""),
LlamadaInicio = xx.Llamada.HoraInicio,
LlamadaFin = xx.Llamada.HoraFin,
Login = xx.Llamada.Sesion.Usuario.Nombre,
campoValor = xx.CampoValor.Select(aux => new CamposGestion() {
Nombre = aux.ConfiguracionCampo.Campo.Nombre,
Valor = aux.Valor
}).ToList()
}).ToList();
But what I want to see the report the field that contains the List show's an error like this
Any help would be appreciate.
I would rewrite the query like this:
var gestiones =
from xx in db.Gestion
where
xx.IDTipificacion == idTipificacion
&& (from T in db.Tipificacion
where T.IdTipificacion == xx.IDTipificacion select T.Servicio.IDServicio).AsEnumerable().Contains(idServicio)
select new GestionesDataSet()
{
GestionInicio = xx.HoraInicio,
GestionFin = xx.HoraFin,
#Tipificacion = (from T in db.Tipificacion where T.IdTipificacion == xx.IDTipificacion select T.Nombre).FirstOrDefault() ?? "",
LlamadaInicio = xx.Llamada.HoraInicio,
LlamadaFin = xx.Llamada.HoraFin,
Login = xx.Llamada.Sesion.Usuario.Nombre,
campoValor = xx.CampoValor.Select(aux => new CamposGestion()
{
Nombre = aux.ConfiguracionCampo.Campo.Nombre,
Valor = aux.Valor
}).ToList()
}).ToList();
When you call a projection (Select) after the AsEnumerable was called, LINQ will try to get the navigation objects first from the already loaded ones. If no object is loaded, then will execute a select SQL command for each navigation property used in the projection. If the [DeferredLoadingEnabled][1] property is set to false it won't execute any query and if no object is loaded already (they can be loaded "apriori" with [LoadWith][2]) it will give a NullReferenceException. So, in some situations, calling AsEnumerable might hurt performance. All these things are not valid when AsEnumerable is used in the where parts.
For giving a default value, when no Tipificacion doesn't exist, it can be used the null-coalescing operator, from C#, instead of using the Count method, which creates an extra lookup on the the table.
Now.. to your problem.
SSRS doesn't support binding to a list of items. The column campoValor tries to bind to a list of objects, which is not allowed. So either you create a subreport (there is a section which describes this) or you flatten your data (having the all the properties on one single object) and then use the HideDuplicates property
I've just learnt how to upload pictures and bring them in view Model.
Now I'm trying to Add comments to the pictures. That means a picture can have more comments.
So I created 2 Tables, called "Gallery" and "Comment". They are related by 'One to Many'..
My model looks like that..
public class GalleryEntries
{
public List Entries { get; set; }
}
public class GalleryEntry
{
public Gallery GalleryImage { get; set; }
public List Comments { get; set; }
}
And the controller looks so..
GalleryDataContext GalleryDB = new GalleryDataContext();
public ActionResult Index()
{
GalleryEntries model = new GalleryEntries();
GalleryEntries galleryentries = new GalleryEntries();
foreach (Gallery gallery in GalleryDB.Galleries)
{
GalleryEntry galleryentry = new GalleryEntry();
galleryentry.Comments = GalleryDB.Comments.Where(c => c.BildID == gallery.ImageID).ToList();
galleryentry.GalleryImage = gallery;
galleryentries.Entries.Add(galleryentry);
}
return View(model);
}
But it doesn't work. :(
It displays "Object reference not set to an instance of an object" at the line where "galleryentries.Entries.Add(galleryentry) stands.. How can I solve this problem?
I think the problem is that you don't initialize the GalleryEntries.Entries property anywhere ... so you're attempting to add galleryentry to a List that does not exist yet, hence the NullReferenceException.
You could initialize Entries in the constructor:
public class GalleryEntries
{
public IList<GalleryEntry> Entries { get; set; }
public GalleryEntries() {
Entries = new List<GalleryEntry>();
}
}
I need simple DropDownList in form and I don't want to create something like ViewModel.
I have two models(tables) in relation 1:n:
public class Course
{
public int ID { get; set; }
public string Name { get; set; }
}
and
public class Project
{
public int ID { get; set; }
public int CourseId { get; set; }
public int ProjectNo { get; set; }
public string Name { get; set; }
public DateTime Deadline { get; set; }
}
In the 'Create Project' I want to have DropDownList with Id (as value) and Name(as text) from Course table(model). In the new project will be insert chosen CourseId. How can I do that as simple as possible?
Any particular reason why you don't want to use a ViewModel? They're very helpful for this type of problem.
If you don't want to use a ViewModel, then you can construct a specific class in your controller that is an aggregate of the properties you need from both classes:
public ActionResult Show(int id)
{
Course course = repository.GetCourse(id); // whatever your persistence logic is here
Project project = projectRepository.GetProjectByCourseId(id);
string CourseName = from c in course where
c.ID == project.courseID
select c.Name;
IEnumerable<SelectListItem> selectList =
from c in course
select new SelectListItem
{
Selected = (c.ID == project.CourseId),
Text = c.Name,
Value = project.CourseId.ToString()
};
//add the selectList to your model here.
return View(); //add the model to your view and return it.
}
It would be far easier to have a ViewModel for this, so you could have a strongly typed view. Let me show you:
public class ProjectCourseViewModel
{
public SelectList ProjectCourseList {get; private set; }
public Project Project {get; private set; }
public Course Course {get; private set; }
public ProjectCourseViewModel(Project project, Course course)
{
ProjectCourseList = GetProjectCourseSelectList(project, course)
Project = project;
Course = course;
}
private SelectList GetProjectCourseSelectList(Project project, Course course)
{
IEnumerable<SelectListItem> selectList =
from c in course
select new SelectListItem
{
Selected = (c.ID == project.CourseId),
Text = c.Name,
Value = project.CourseId.ToString()
};
}
}
And then your controller would be really simple:
public ActionResult Show(int id)
{
Course course = repository.GetCourse(id);
Project project = projectRepository.GetProjectByCourseId(id);
ProjectCourseViewModel pcvm = new ProjectCourseViewModel(project, course)
return View(pcvm);
}
And then your view takes in a strongly typed model, and you don't have to rely on ViewData, which is a Good Thing.
Note: I haven't compiled this, just written it. There are probably compilation bugs.
probably you could solve it using the following example:
in your controller include a Viewbag
{
Viewbag.Course = db.course.ToList();
var project = new project.....
}
And in your View use the following pattern:
#Html.DropDownList("CourseId",
new SelectList(ViewBag.Course as System.Collections.IEnumerable,
"CourseId", "Name", Model.ID))
where each field represent:
•The name of the form field (CourseId)
•The list of values for the dropdown, passed as a SelectList
•The Data Value field which should be posted back with the form
•The Data Text field which should be displayed in the dropdown list
•The Selected Value which is used to set the dropdown list value when the form is displayed
more info at: http://www.asp.net/mvc/tutorials/mvc-music-store-part-5
brgds.
In the Controler:
var CourseName = from c in course where
c.ID == project.courseID
select c.Name;
SelectList sl = new SelectList(CourseName);
ViewBag.names= sl;
in the view :
#Html.DropDownList("Name", (SelectList)ViewBag.names)