I have a master-detail relationship in some custom entities. Say I have the following structure:
class Master : INotifyPropertyChanged
{
public int Id { get; set; } // + property changed implementation
public string Name { get; set; } // + property changed implementation
public ObservableCollection<Detail> Details { get; }
public long sumValue{get{return Details.Sum(x=>x.value -x.discount );}}
}
class Detail : INotifyPropertyChanged
{
public int Id { get; private set; }
public string Description { get; set; }
public double Discont{ get; set; } // + property changed implementation
public double Value { get; set; } // + property changed implementation
}
if i change row 5 in detail discount Or value How can refresh sumValue?
i add row 1 and set amount 1 and row sum row is 2000
and add new row 2 set amount 5 and row sum is 10000
but sum in master frezz on last row 2000!
if i call
NotifyPropertyChange("sumValue");
from master ui updated sumvalue Property!
how can i use
NotifyPropertyChange("sumValue");
from master Property in Detail Property
like this:
public double Discont{ get{ return _discount } set{_discount = value; NotifyPropertyChange("sumValue");} }
You need to listen on the CollectionChanged of your Details and on any PropertyChanged event of the details in the list.
The CollectionChanged event will tell you when objects are added, removed, moved or replaced in the list. But the ObservableCollection does not listen on PropertyChanged events on its content, so you need to do it on your own.
See this answer as a reference how you can do that
Related
Good day!
I'm having an issue with the DevExpress LookUpEdit I can't figure out what the problem is.
I'm use Entity Framework list as a datasource.
public partial class provider_scheme : BaseEntity
{
public provider_scheme()
{
}
public int Provider_Scheme_RowID { get; set; }
public int Currency_RowID { get; set; }
public string Provider_Scheme_Name { get; set; }
public virtual currency currency { get; set; }
}
public partial class currency : BaseEntity
{
public currency()
{
provider_scheme = new HashSet<provider_scheme>();
}
public int Currency_RowID { get; set; }
public string Currency_ISOCode { get; set; }
public virtual ICollection<provider_scheme> provider_scheme { get; set; }
}
I'm setting the Datasource property of the LookUpEdit to IEnumerable<provider_scheme>, and setting up two column field names in my LookUpEdit. One for 'Provider_Scheme_Name' and one for 'currency.Currency_ISOCode'. But for some reason only the 'Provider_Scheme_Name' column values are showing. I've also checked and the 'currency' navigation property is being loaded.
Thanks in advance for your help
A bit late for an answer, but you might consider using the GridLookupEdit control instead. It permits adding all the columns you want
I feel like I'm missing something obvious here; I'm using .Net 5 with Entity Framework Core. The problem is that the foreign key is correct, but the associated navigation property is always empty and has no data. Do I have to do something with the fluent framework, or do something special with my includes?
I have 3 simplified entities and a database context method in this example, the project is much too large to include entirely. In the method, CalendarEvents is a DbSet:
public class CalendarEvent: IJsonSerializable
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
/// <summary>
/// Gets the personnel associated with this event
/// </summary>
public virtual List<SchedulePerson> SchedulePeople { get; set; } = new List<SchedulePerson>();
}
public class SchedulePerson : IJsonSerializable, ICloneable
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public int EmployeeId { get; set; }
public virtual Employee Employee { get; set; }
public virtual CalendarEvent AssociatedCalendarEvent { get; set; }
}
public class Employee : IJsonSerializable
{
[Key]
public int Id { get; set; }
public virtual List<SchedulePerson> AssociatedSchedulePeople { get; set; } = new List<SchedulePerson>();
}
public class DbContext : DbContext
{
public DbSet<CalendarEvent> CalendarEvents { get; set; }
public DbSet<SchedulePerson> SchedulePeople { get; set; }
public DbSet<Employee> Employees { get; set; }
public DbContext(DbContextOptions<VibrationContext> options): base(options)
{
}
public CalendarEvent GetEvent(int calendarEventId)
{
var currentCalEvent = this.CalendarEvents.Where(x => x.Id == calendarEventId);
var dummy1 = currentCalEvent.FirstOrDefault();
var dummy2 = currentCalEvent.Include(calEvent => calEvent.SchedulePeople).ToList();
var dummy3 = currentCalEvent.Include(calEvent => calEvent.SchedulePeople).ThenInclude(people => people.Employee).ToList();
return currentCalEvent.FirstOrDefault();
}
}
In this case Employee is the associated navigation property, and the associated key EmployeeId, is correct. For the moment I've added extra logic that will populate each employee per schedule person separately, manually based on the foreign key EmployeeId, when I get the event, but I'd rather not have to add logic like that each time. If that's something unavoidable then that's fine, but I'd like to do things properly and let Entity Framework Core handle as much as possible.
For additional context:
SchedulePerson -> CalendarEvent is a many-to-one relationship
Employee -> SchedulePerson is a many-to-one relationship
In other words a calendar event can contain many schedule persons, but a schedule person can only be associated with one calendar event.
Employee can be associated with many schedule persons, but each schedule person is only associated with one employee.
There should only be one employee for each real person, but there can be multiple SchedulePersons for each real person.
Thank you for your help and let me know if there is any more information I can provide.
Also if anything else looks bad or wrong in these code snippets please let me know.
Edit, this is what I have to do if I want to get the employees in my request:
private void UpdateEmployeeContents(CalendarEvent calendarEvent)
{
foreach (SchedulePerson person in calendarEvent.SchedulePeople)
{
person.Employee = this.Employees.Where(x => x.Id == person.EmployeeId).FirstOrDefault();
}
}
Overview
I am designing a mechanism for generating dynamic controls in an ASP.NET MVC application that uses ADO.NET Entity Framework. However, my question has nothing to do with MVC and a little to do with the Entity Framework. It is about comparing two object models.
Problem Statement
In my app, a user must have the ability to interact with Web page A to specify that he wants to add such and such HTML controls to Web Page B.
When he browses Web Page B next, he must see those controls and be able to use them.
What Is Not The Challenge
I have written the code to generate the controls. That was the easy part. I used the Tag Builder, Partial Views, HtmlHelper extensions and Display & Editor templates.
The Challenge
The challenge is in arriving at a database design and an object model generated by Entity Framework to hold the metadata about the controls that need to be generated.
I have come up with a database design as shown below:
You may ignore the User and Permissions tables. They are not relevant to our discussion.
Entity Framework generates the following entities based on the above database design.
Let's call my database design as Design Option A.
I would have wanted a design that looked more like this:
Let's call this second design as Design Option B.
The code (stripped down version) for this second option would look like this:
namespace DynamicControls
{
public class DynamicControlGroup
{
public long Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public string Controller { get; set; }
public IEnumerable<string> Actions { get; set; }
public DateTime StartDate { get; set; }
public DateTime? EndDate { get; set; }
public User CreatedByUser { get; set; }
public DateTime CreationDateTime { get; set; }
public User LastModifiedBy { get; set; }
public DateTime ModificationDateTime { get; set; }
// Navigational
public ICollection<DynamicControl<T>> DynamicControls { get; set; }
}
public class DynamicControl<T>
{
public long Id { get; set; } //db Id
public string HtmlId { get; set; }
public bool ValueRequired { get; set; }
public virtual ControlType ControlType { get; protected set; }
// Every control is capable of having a default value but of a different
// type. Most controls have default values of type text (string). The
// multi-select ones (checkboxes, multi-select lists, etc.) have a default
// value of type IEnumerable<string>. So, I want to leave this generic.
// But I am not that hung-up on this. I am fine if I am required to move
// this property DefaultValue from the base class and make it a concrete
// (not generic) property for each individual child class.
// Mostly I just want the heirarchy. And before that, I want to know
// if it is a good idea to model this heirarchy. Or is it better to just
// work with what my Entity Framework produced for my db?
// Should I change my db? I can because I thought-up the design for
// those tables.
public virtual T DefaultValue { get; set; }
// Navigational
public DynamicControlGroup DynamicControlGroup { get; set; }
}
public class TextBox : DynamicControl<string>
{
public override ControlType ControlType
{
get
{
return DynamicControls.ControlType.TextBox;
}
}
public string Label { get; set; }
public int MaxLength { get; set; }
}
public class PasswordControl : TextBox
{
public override ControlType ControlType
{
get
{
return DynamicControls.ControlType.Password;
}
}
}
public class TextArea : TextBox
{
public override ControlType ControlType
{
get
{
return DynamicControls.ControlType.TextArea;
}
}
public int Rows { get; set; }
}
public class DropDownList: DynamicControl<string>
{
public override ControlType ControlType
{
get
{
return ControlType.DropDownList;
}
}
// I want something like this. That I should be able to say
//
// myDropDownListObject.Options...
//
// You'll notice that given my current database design, I have
// no direct way of accessing the options of a, say, drop down list.
// To do that, I have to make a round-about Linq query.
public ICollection<DynamicControlOption> Options { get; set; }
}
public class DynamicControlOption
{
public long Id { get; set; } // db Id
public string OptionHtmlId { get; set; }
public string OptionValue { get; set; }
public string OptionText { get; set; }
// Navigational property
public DynamicControl<IEnumerable<string>> TheControlWhoseOptionIAm { get; set; }
}
public class User
{
}
public class Permission
{
}
public enum ControlType
{
TextBox,
TextArea,
Password,
RadioButton,
Checkbox,
DropDownList,
MultiSelectList,
DatePicker,
TimePicker,
DateTimePicker
}
}
My Question
1) I feel that I'd like Design Option B better. Am I feeling right?
2) I know I can work with Design Option A just as fine but it'll involve a little round-about way to do some things. For example, to get all the options for a drop down list, there's not navigational property on the DropDownList class in Design Option A. I'll have to write a round-about Linq query to do that.
3) Is it possible to have Entity Framework come close to generating Design Option B? How? What changes will I need to make to my database design to achieve that?
Now we are working on a Project like this at our company...
If I got your meaning correctly and If I were you...I implemented inherited structure as my database design like below.
Now you Classes are inheritance but your database design is not.
I have removed Id in TextBox and I have put ControlId as PK and FK in the same time. (not just FK).
in fact,ControlId is both PK for TextBox and FK from DynamicControl
and also this way for PasswordControl and TextArea
and Now ControlId in TextBox is not Identity. It gets it's ControlId from DynamicControl
I also accept Design Option B .I'm always more comfortable than using Design Option A.in my idea It's true and main structure
I'm using Entity Framework for the first time (database first, entity framework 5) in a windows forms application (vs2010, .net 4). I am having trouble with the binding between my entity object and the windows forms controls. I have textbox, datetimepicker and combobox controls. When I open a window with the bound controls, the correct data is displayed in the controls. However, when I change the value in one of my controls and tab off the control, the value reverts to the original value in the control as if the value is not getting pushed to the object. Here are code exerpts:
My entity object:
namespace Entities
{
using System;
using System.Collections.Generic;
public partial class ExternalDocument
{
public int ExternalDocumentID { get; set; }
public bool Active { get; set; }
public bool Closed { get; set; }
public Nullable<int> CompanyID { get; set; }
public Nullable<int> ContactID { get; set; }
public string DocumentNbr { get; set; }
public Nullable<System.DateTime> DocumentDate { get; set; }
public Nullable<System.DateTime> DateReceived { get; set; }
public virtual Company Company { get; set; }
public virtual Contact Contact { get; set; }
}
}
The data binding:
private void SetDataBindings()
{
LoadComboBoxValues();
this.textDocumentNbr.DataBindings.Add("Text", this.document, "DocumentNbr");
this.textDocumentNbr.Leave += new EventHandler(textDocumentNbr_Leave);
this.dateDocument.DataBindings.Add(new Binding("Value", this.document, "DocumentDate"));
this.dateReceived.DataBindings.Add("Value", this.document, "DateReceived");
this.comboCompanyID.DataBindings.Add("SelectedValue", document, "CompanyID");
}
I have wondered if there is an entity framework error when the object property is set but I have not been able to figure out a good way to trap any such errors. My entity framework object does not have the On< PropertyName >Changing methods that are created for earlier versions of entity framework. I have been trying to trap errors when focus leaves the control but think this can't be the best method:
private void dateDocument_Leave(object sender, EventArgs e)
{
string errorString = this.entitiesController.GetValidationErrors();
this.errorDocumentDate.SetError(this.dateDocument, errorString);
}
public string GetValidationErrors()
{
string errorString = "";
List<DbEntityValidationResult> errorList = (List<DbEntityValidationResult>)this.finesse2Context.GetValidationErrors();
if (errorList.Count > 0)
{
foreach(var eve in errorList)
{
errorString += "Entity of type " + eve.Entry.Entity.GetType().Name + " in state" + eve.Entry.State + " has the following validation errors:"; ;
foreach (var ve in eve.ValidationErrors)
{
errorString += "- Property: " + ve.PropertyName + " Error: " + ve.ErrorMessage;
}
}
}
return errorString;
}
Any help would be appreciated. Thanks!
It turns out that an exception is received when the binding pushes a non nullable value to a nullable property in the object unless "formattingEnabled" is specified on the binding.
So, binding like this works:
this.dateDocument.DataBindings.Add(new Binding("Value", this.document, "DocumentDate", true));
whereas this does not:
this.dateDocument.DataBindings.Add(new Binding("Value", this.document, "DocumentDate"));
I am still unclear how I could trap that type of error since the Binding simply catches the error and replaces the value in the control with the original value.
I am having problems databinding to EF code first. I need to be using Eager Loading, but I am running into some issues with databinding. I have the following classes:
public class Context : DbContext
{
DbSet<A> As;
DbSet<B> Bs;
DbSet<C> Cs;
}
public class A
{
public ICollection<B> Bs { get; set; }
public string Name { get; set; }
}
public class B
{
public ICollection<C> Cs { get; set; }
public string Name { get; set; }
}
public class C
{
public string Name { get; set; }
}
I am data binding Context.As to a Treeview, using the below code:
Context.As.Load();
tvItems.ItemsSource = Context.As.Local;
This works as expected, however, it does not automatically load the child properties, Bs, and subsequently, Cs. So, I found that lazy loading can help with this, like so:
Context.As.Load();
tvItems.ItemsSource = Context.As.Include(u=>u.Bs);
From my reading, this should automatically load at least the first level of child properties. However, this will not data bind, as I did not use .Local
.Include() returns IQueryable, which does not support .Local. I can use .ToList(), but this will not automatically update when I add items.
So, how the hell am I supposed to be doing this?
You could try this:
Context.As.Include(a => a.Bs).Load();
tvItems.ItemsSource = Context.As.Local;