Why this work :
public Form1()
{
InitializeComponent();
exCheckedListBox1.DataSource = Profiles;
this.exCheckedListBox1.DataBindings.Add(new System.Windows.Forms.Binding("Tag", this, "States", true));
}
CheckedBindingList Profiles = new CheckedBindingList();
public int States
{
get
{
return Profiles.States;
}
set
{
Profiles.States = value;
}
}
}
public class CheckedBindingList : List<string>
{
public int States { get; set; }
}
but when change binding to
this.exCheckedListBox1.DataBindings.Add(new System.Windows.Forms.Binding("Tag", this.Profiles, "States", true));
throw the Exception ?
Thanks all very very very. I try to bind filed from my custom list class that inherit form List.
Exception - Cannot bind to the property or column States on the DataSource.
Parameter name: dataMember
Seems System.Windows.Forms.Binding parameter dataSource cannot be a class that inherits from List< T >
This solves the problem:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Load += new EventHandler(Form1_Load);
}
CheckedBindingList Profiles = new CheckedBindingList();
SomeClass some_class = new SomeClass();
public int States
{
get
{
return Profiles.States;
}
set
{
Profiles.States = value;
}
}
private void Form1_Load(object sender, EventArgs e)
{
exCheckedListBox1.DataSource = Profiles;
exCheckedListBox1.DataBindings.Add(new System.Windows.Forms.Binding("Tag", some_class, "States", true));
}
}
public class CheckedBindingList : List<string>
{
public int States { get; set; }
}
public class SomeClass
{
public int States { get; set; }
}
Related
How to notify the modification of an interface that changes in a DLL on the bindings side.
To explain:
Dll code is not editable:
public interface IPlayer
{
int Id { get; }
string Name { get; }
Settings Settings { get; }
PlayerCategory Category { get; }
}
public class TennisPlayer: IPlayer
{
public virtual int Id { get; }
public virtual string Name { get; set; }
public Tennisman(int id, string name)
{
Id = id;
Name = name;
}
public Settings Settings { get; set; }
public PlayerCategory Category { get; set; }
}
My code:
public partial class PlayerItem : NotifyUserControl
{
private DispatcherTimer timer = new DispatcherTimer();
public static readonly DependencyProperty PlayerProperty =
DependencyProperty.Register("Player", typeof(IPlayer),
typeof(PlayerItem),
new PropertyMetadata(null, OnCaptionPropertyChanged));
public IPlayer Player
{
get { return (IPlayer)GetValue(PlayerProperty); }
set
{
SetValue(PlayerProperty, value);
}
}
public string PlayerName
{
get => Player != null ? Player.Name : "";
set => OnPropertyChanged();
}
public PlayerItem()
{
InitializeComponent();
timer.Interval = new TimeSpan(0, 0, 4);
timer.Tick += Timer_Tick;
timer.Start();
}
private void Timer_Tick(object sender, EventArgs e)
{
OnPropertyChanged(nameof(PlayerName));
}
The external dll gives me player classes( for example: tennisman, footballer...) based on the same interface.
But I don't know it and I don't have to do class by class.
I must be missing something huge, but I managed to find nothing in my research.
I'm new to WPF and MVVM and i've an applicaton that uses Entity Framework to connect to database and a datagrid to show the users of the application.
The users CRUD operations are made in a separate window and not in the datagrid.
My problems are related with the update of datagrid.
The insert operation is ok but the update is not.
View 1 (Users List):
<DataGrid Grid.Row="1"
ItemsSource="{Binding Users, Mode=TwoWay}"
SelectedItem="{Binding SelectedUser, Mode=TwoWay}"
AutoGenerateColumns="False"
CanUserAddRows="False">
</DataGrid>
ViewModel :
class UserListViewModel: NotificationClass
{
UserDBContext _db = null;
public UserListViewModel()
{
_db = new UserDBContext();
Users = new ObservableCollection<User>(_db.User.ToList());
SelectedUser = Users.FirstOrDefault();
}
private ObservableCollection<User> _users;
public ObservableCollection<User> Users
{
get { return _users; }
set
{
_users = value;
OnProprtyChanged();
}
}
private User _selectedUser;
public User SelectedUser
{
get
{
return _selectedUser;
}
set
{
_selectedUser = value;
OnProprtyChanged();
}
}
public RelayCommand Edit
{
get
{
return new RelayCommand(EditUser, true);
}
}
private void EditUser()
{
try
{
UserView view = new UserView();
view.DataContext = SelectedUser;
view.ShowDialog();
if (view.DialogResult.HasValue && view.DialogResult.Value)
{
if (SelectedUser.Id > 0){
User updatedUser = _db.User.First(p => p.Id == SelectedUser.Id);
updatedUser.Username = SelectedUser.Username; //this doesn't do nothing, object is already with the new username ?!
}
_db.SaveChanges();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
after _db.SaveChanges(), datagrid should not be updated ?
Model:
class UserDBContext: DbContext
{
public UserDBContext() : base("name=DefaultConnection")
{
}
public DbSet<User> User { get; set; }
}
View 2 (User detail)
public partial class UserView : Window
{
public UserView()
{
InitializeComponent();
}
private void SaveButton_Click(object sender, RoutedEventArgs e)
{
DialogResult = true;
}
}
User object
class User: NotificationClass
{
public int Id { get; set; }
public string Username { get; set; }
public string CreatedBy { get; set; }
public DateTime? CreatedOn { get; set; }
}
NotificationClass
public class NotificationClass : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged = delegate { };
public void OnProprtyChanged([CallerMemberName]string propertyName = null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
if i close and open view 1, the new username is updated..
could someone help ? thanks
Just implementing INotifyPropertyChanged isn't enough, you have to explicitly invoke PropertyChanged (or in your case OnPropertyChanged) when a property changed.
See also https://learn.microsoft.com/en-us/dotnet/framework/wpf/data/how-to-implement-property-change-notification
You can do it like so
class User : NotificationClass
{
private int _id;
private string _username;
private string _createdBy;
private DateTime? _createdOn;
public int Id
{
get => _id;
set
{
if (value == _id) return;
_id = value;
OnPropertyChanged();
}
}
public string Username
{
get => _username;
set
{
if (value == _username) return;
_username = value;
OnPropertyChanged();
}
}
public string CreatedBy
{
get => _createdBy;
set
{
if (value == _createdBy) return;
_createdBy = value;
OnPropertyChanged();
}
}
public DateTime? CreatedOn
{
get => _createdOn;
set
{
if (value.Equals(_createdOn)) return;
_createdOn = value;
OnPropertyChanged();
}
}
}
it worked ! many thanks #nosale !
what about the change made to SelectedUser being reflected in my context ?
if i do this :
SelectedUser.Username = "test";
User updatedUser = _db.User.First(p => p.Id == SelectedUser.Id);
i was thinking that SelectedUser object has the "test" username and updatedUser has the old username, but not .. updatedUser already have "test"
I'am new to WPF and MVVM and I was given the task to continue working on one of the unfinished project that is made using the said technology. I've written a sample code below that is similar to the structure of the project.
My concern is, the loop used in GetBookPages() to display the details on the grid might take some time to finish.
public class BookModel
{
public string BookTitle { get; set; }
public List<BookDetailModel> BookDetails { get; set; }
}
public class BookDetailModel
{
public int Pages { get; set; }
public string Others { get; set; }
// ....
}
public class BookViewModel : INotifyPropertyChanged
{
private BookModel _model;
private ObservableCollection<BookDetailViewModel> _bookDetailSource;
private BookService _service;
public BookViewModel()
{
_model = new BookModel();
_service = new BookService();
GetBookPages();
}
/// <summary>
/// This is the item source of datagrid that is located in view
/// </summary>
public ObservableCollection<BookDetailViewModel> BookDetailSource
{
get { return _bookDetailSource; }
set
{
if (value == _bookDetailSource)
return;
_bookDetailSource = value;
OnPropertyChanged();
}
}
private void GetBookPages()
{
BookModel bookModel = _service.GetBookData();
var listOf = new List<BookDetailViewModel>();
bookModel.BookDetails.ForEach(e =>
{
// This is were the system's bottle neck is.
// can someone please suggests me a good work around.
listOf.Add(
new BookDetailViewModel
{
Others = e.Others,
// ....
});
});
BookDetailSource = new ObservableCollection<BookDetailViewModel>(listOf);
}
public string BookTitle
{
get { return _model.BookTitle; }
set
{
if (value == _model.BookTitle)
return;
_model.BookTitle = value;
OnPropertyChanged();
}
}
#region Property Change
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
public class BookDetailViewModel : INotifyPropertyChanged
{
private BookDetailModel _model;
#region Constructor
public BookDetailViewModel()
{
_model = new BookDetailModel();
ViewPageDataCommand = new RelayCommand(x => ViewPageData());
RemovePageCommdand = new RelayCommand(x => RemovePage());
}
#endregion
#region Properties
public int Page
{
get { return _model.Pages; }
set
{
if (value == _model.Pages)
return;
_model.Pages = value;
OnPropertyChanged();
}
}
public string Others
{
get { return _model.Others; }
set
{
if (value == _model.Others)
return;
_model.Others = value;
OnPropertyChanged();
}
}
#endregion
// These are the button command inside the grid's row
public ICommand ViewPageDataCommand { get; private set; }
public ICommand RemovePageCommdand { get; private set; }
private void ViewPageData()
{
// view the page data by clicking the row button inside the grid
}
private void RemovePage()
{
// will remove the currently selected row inside the grid
}
#region Property Change
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
public class BookService
{
public BookModel GetBookData()
{
var data = GetBookData(99);
data.BookDetails = GetBookDetail(99);
return data;
}
private BookModel GetBookData(int bookId)
{
// return 1 row only
}
private List<BookDetailModel> GetBookDetail(int bookId)
{
// return List<BookDetailModel> that might consists of more than 100 index's
}
}
I hope you understand what I mean. Your suggestion will be much appreciated. Thanks in advance!
Trying to implement simple validation with caliburn. All I want is to enable/disable save button based on certain conditions.
View:
`<xctk:MaskedTextBox x:Name="pm_personId" cal:Message.Attach="[Event LostFocus] = [Action CanSave()]" Mask="00-000-000?"/>
<Button Content="Save" x:Name="Save" />`
Model:
public class PersonModel
{
public String personId { get; set; }
public PersonModel() {}
public PersonModel(String id)
{
this.id = personId;
}
}
ViewModel:
[ImplementPropertyChanged]
public class PersonViewModel : Screen
{
public PersonModel pm { get; set; }
public PersonViewModel()
{
pm = new PersonModel();
}
public bool CanSave()
{
MessageBox.Show(pm.personId);
if (pm.personId != null)
return true;
else return false;
}
}
The MessageBox is fired with the right value but button is not enable. Am I missing anything. Either am missing something with caliburn or it's doing too much magic. Am beginning to suspect that the time it may save you initially will be lost in debugging, just my exeprience.
Thanks #CCamilo but your answer was incomplete. For other people who encounter a similar problem, below is my final working code:
[ImplementPropertyChanged]
public class PersonModel
{
public String personId { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
public PersonModel() {}
public PersonModel(String id)
{
this.id = personId;
}
}
[ImplementPropertyChanged]
public class PersonViewModel : Screen
{
public PersonModel pm { get; set; }
public PersonViewModel()
{
pm = new PersonModel();
this.pm.PropertyChanged += pm_PropertyChanged;
}
void pm_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
NotifyOfPropertyChange(() => CanSave);
}
public bool CanSave
{
get { return pm.personId != null; }
}
}
The error you have is with CanSave() method.. It should be a property instead:
public bool CanSave
{
get
{
if (pm.personId != null)
return true;
else return false;
}
}
I'm trying to follow the MVVM pattern, however I spent some good time on this issue, googled a lot and checked stackoverflow as well... No working example found so far.
Basically, I've a simple application and want to retrieve and write data to SQL server. Here's my code:
//Model
public class Visitor
{
public string ID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
//ViewModel
public class VisitorViewModel : ViewModelBase
{
public ObservableCollection<Visitor> _visitorDataCollection = new ObservableCollection<Visitor>();
public ObservableCollection<Visitor> VisitorDataCollection
{
get { return _visitorDataCollection; }
set { _visitorDataCollection = value; }
}
private string _firstName = "";
private string _lastName = "";
public string FirstName
{
get { return _firstName; }
set
{
if (value != _firstName)
{
_firstName = value;
OnPropertyChanged("FirstName");
}
}
}
public string LastName
{
get { return _lastName; }
set
{
if (value != _lastName)
{
_lastName = value;
OnPropertyChanged("LastName");
}
}
}
public VisitorViewModel()
{
}
}
}
//VisitorContext class that represents a database context
public partial class VisitorContext : DbContext
{
public VisitorContext()
: base()
{
}
public DbSet<VISITOR> Visitors { get; set; }
}
}
Nothing really fancy. However, I cannot put it "together". How to complete that to retrieve all visitors and add a new one?
Could someone point me to the right direction?
Just a simple example how make it all to life.
Add some commands to VM:
public ICommand Add {get; private set;}
In constructor:
public VisitorViewModel()
{
using(var context = new VisitorContext())
{
//fill collection with initial data from DbContext
context.Visitors.ToList().ForEach(_visitorDataCollection.Add);
}
//setup add command, here I'm using MVVM Light like you
Add = new RelayCommand(()=> {
using(var context = new VisitorContext())
{
_visitorDataCollection.Add(context.Visitors.Add(new Visitor {
FirstName = this.FirstName,
LastName = this.LastName //read values from model properties
});
}
});
}
That's it, all you need to do is bind this ViewModel to appropriate View.