My ViewModel changes are not reflected in my UI - c#

I have two bound textboxes in my View.
<TextBox Text="{Binding BookingWizard.CustomerView.Email,Mode=TwoWay}" />
<TextBox Text="{Binding BookingWizard.CustomerView.ContactNo,Mode=TwoWay}" />
I can populate these fields when another textbox has lost its focus. the code behind for that bit is:
private void txtFirstName_LostFocus(object sender, RoutedEventArgs e)
{
LookUpEmailAndContactNo();
}
private void LookUpEmailAndContactNo()
{
var vm = this.DataContext as ApplicationViewModel;
var customer = vm.BookingWizard.LookUpEmailAndContactNo();
//etc
vm.BookingWizard.CustomerView.Email = customer.Email;
}
public Customer LookUpEmailAndContactNo()
{
var res= InformedWorkerBusinessService.Customer.GetEmailAndContactNo(CustomerView.FName, CustomerView.SName);
if (res!=null)
{
CustomerView.Email = res.Email;
CustomerView.ContactNo = res.ContactNo;
}
return CustomerView;
}
This is the screenshot of my data context when i set a break-point in the LookUpEmailAndContactNo event:
As you can see the data context does have these values but I cannot see what is wrong with my UI binding?
ADDITIONAL:
I set my view model at the App entry point:
public partial class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
ApplicationView app = new ApplicationView();
ApplicationViewModel context = new ApplicationViewModel();
context.ActiveRecord = new ActiveRecord();
context.CustomerSearch = new CustomerSearch();
context.BookingWizard = new BookingWizard();
context.BookingWizard.CustomerView = new InformedWorkerModel.Customer();
context.BookingWizard.JobView = new InformedWorkerModel.Job();
app.DataContext = context;
app.Show();
}
}
This is inside my BookingWizard class:
public class BookingWizard : ViewModelBase, IDataErrorInfo
{
Customer _Customer;
public bool IsExistingCustomer { get; set; }
public IEnumerable<string> FNames
{
get
{
if (CustomerView.SName == null)
{
CustomerView.SName = string.Empty;
}
return InformedWorkerBusinessService.Customer.GetFirstNames(CustomerView.SName);
}
}
public Customer LookUpEmailAndContactNo()
{
var res= InformedWorkerBusinessService.Customer.GetEmailAndContactNo(CustomerView.FName, CustomerView.SName);
if (res!=null)
{
CustomerView.Email = res.Email;
CustomerView.ContactNo = res.ContactNo;
}
return CustomerView;
}
public Customer CustomerView
{
get { return _Customer; }
set
{
_Customer = value; RaisePropertyChanged("CustomerView");
}
}
}
and in my Customer Class:
[Table("Customer")]
public class Customer
{
[AutoIncrement]
[PrimaryKey]
public int CustomerId { get; set; }
public string SName { get; set; }
public string FName { get; set; }
public string ContactNo { get; set; }
public string Email { get ; set; }
}

Related

Winforms ListBox with DataSource bound to dotted path of nested object crashes when intermediate object of dotted path is null

The ListBox's DataSource is bound to Detail.Tags.
When I select the first row, ListBox populates as expected.
When I select the second row, the expected (and desired) result is that the ListBox simply displays nothing, because ItemB's Detail property is purposely null for demonstration purposes, so ItemB's Detail.Tags doesn't exist.
Actual result is that program crashes to desktop with System.ArgumentException: 'Complex DataBinding accepts as a data source either an IList or an IListSource.'
Minimal reproducible example:
public partial class Form1 : Form
{
private readonly IList<Item> _items;
private BindingSource _bs = new BindingSource(){ DataSource = typeof(Item) };
public Form1()
{
InitializeComponent();
_items = GenerateSampleItems();
}
private void Form1_Load(object sender, EventArgs e)
{
dataGridView1.DataSource = _items;
listBox1.DataBindings.Add(new Binding("DataSource", _bs, "Detail.Tags", false, DataSourceUpdateMode.Never));
}
private void DataGridView1_SelectionChanged(object sender, EventArgs e)
{
if (dataGridView1.SelectedRows.Count == 1)
{
_bs.DataSource = dataGridView1.SelectedRows[0].DataBoundItem;
}
else
{
_bs.DataSource = typeof(Item);
}
}
private IList<Item> GenerateSampleItems()
{
return new List<Item>()
{
new Item()
{
Name = "ItemA"
,Detail = new Detail()
{
Expiration = new DateTime(2024,1,1)
,Tags = new BindingList<Tag>(new List<Tag>()
{
new Tag()
{
TagName = "FirstT"
,TagValue = "FirstV"
}
,new Tag()
{
TagName = "SecondT"
,TagValue = "SecondV"
}
})
}
}
,new Item()
{
Name = "ItemB"
// Detail purposely omitted
}
,new Item()
{
Name = "ItemC"
// Detail purposely omitted
}
};
}
}
class Item
{
public string Name { get; set; }
public Detail Detail { get; set; }
}
public class Detail
{
public DateTime Expiration { get; set; }
public BindingList<Tag> Tags { get; set; }
}
public class Tag
{
public string TagName { get; set; }
public string TagValue { get; set; }
}
You can solve this problem by Creating a BindingSource for each model:
Main BindingSource where its DataSource property is set to a list of Item. This one is the DataGridView.DataSource.
Second BindingSource to navigate the Detail data members of the main BindingSource.
Third one to navigate and display the Tags data members of the detail's BindingSource. This one is the ListBox.DataSource.
public partial class Form1 : Form
{
private IList<Item> _items;
private BindingSource _bsItems, _bsDetail, _bsTags;
public Form1()
{
InitializeComponent();
}
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
_items = GenerateSampleItems();
_bsItems = new BindingSource(_items, null);
_bsDetail = new BindingSource(_bsItems, "Detail");
_bsTags = new BindingSource(_bsDetail, "Tags");
dataGridView1.DataSource = _bsItems;
listBox1.DataSource = _bsTags;
}
protected override void OnFormClosed(FormClosedEventArgs e)
{
base.OnFormClosed(e);
_bsItems.Dispose();
_bsDetail.Dispose();
_bsTags.Dispose();
}
private IList<Item> GenerateSampleItems()
{
return new List<Item>()
{
new Item()
{
Name = "ItemA",
Detail = new Detail
{
Expiration = new DateTime(2024,1,1),
Tags = new BindingList<Tag>(new List<Tag>()
{
new Tag
{
TagName = "FirstT",
TagValue = "FirstV"
},
new Tag
{
TagName = "SecondT",
TagValue = "SecondV"
}
})
}
},
new Item()
{
Name = "ItemB"
// Detail purposely omitted
},
new Item()
{
Name = "ItemC"
// Detail purposely omitted
}
};
}
}
// Elsewhere within the project's namespace
public class Item
{
public string Name { get; set; }
public Detail Detail { get; set; }
// Optional: Change, remove as needed...
public override string ToString()
{
return $"Name: {Name} - Detail: {Detail}";
}
}
public class Detail
{
public DateTime Expiration { get; set; }
public BindingList<Tag> Tags { get; set; }
// Optional: Change, remove as needed...
public override string ToString()
{
var tags = $"[{string.Join(", ", Tags)}]";
return $"Expiration: {Expiration} - Tags: {tags}";
}
}
public class Tag
{
public string TagName { get; set; }
public string TagValue { get; set; }
// Optional: Change, remove as needed...
public override string ToString()
{
return $"{TagName}: {TagValue}";
}
}
That's all. No need to add DataBindings nor to handle the grid's SelectionChanged event as shown in your code snippet.
On the other hand, if you need to display the selected Item.Detail.Tags, then you need to flatten them in a list whenever the grid's selection changes and bind the result to the ListBox.
// +
using System.Linq;
public partial class Form1 : Form
{
private BindingSource _bsItems;
public Form1() => InitializeComponent();
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
_bsItems = new BindingSource(GenerateSampleItems(), null);
dataGridView1.DataSource = _bsItems;
}
protected override void OnFormClosed(FormClosedEventArgs e)
{
base.OnFormClosed(e);
_bsItems.Dispose();
}
private void dataGridView1_SelectionChanged(object sender, EventArgs e)
{
listBox1.DataSource = dataGridView1.SelectedCells
.Cast<DataGridViewCell>()
.Select(cell => cell.OwningRow).Distinct()
.Where(row => (row.DataBoundItem as Item)?.Detail != null)
.SelectMany(row => (row.DataBoundItem as Item).Detail.Tags)
.ToList();
}
}

UWP C# How to append .json file and to identify them in groups

I am trying to create a usercontrol to display groups of items from json file on windows iot core.
I have a "Create Group" button. Once pressed, it will create 64 usercontrols with respective details and display in a scrollviewer. susequently i can edit individual items in any of the 64 usercontrol then save the json file.
I have my class for the usercontrol as follow;
I have having an issue on how to create different groups of the 64 items and append all in a same json file and to subsequently display them from selection of the mentioned different groups.
Please help thanks.
Group Class
[DataContract]
public class DecoderGroup
{
[DataMember]
public int groupID{ get; set; }
[DataMember]
public string groupName{ get; set; }
[DataMember]
public int cardAddress { get; set; }
[DataMember]
public bool enabled { get; set; }
[DataMember]
public int z1label { get; set; }
[DataMember]
public int z2label { get; set; }
[DataMember]
public int z3label { get; set; }
[DataMember]
public int z4label { get; set; }
[DataMember]
public bool zone1 { get; set; }
[DataMember]
public bool zone2 { get; set; }
[DataMember]
public bool zone3 { get; set; }
[DataMember]
public bool zone4 { get; set; }
[DataMember]
public List<byte> txData { get; set; }
public DecoderGroup(int id, int address, int z1, int z2, int z3, int z4)
{
groupName = "Group";
zone1 = false;
zone2 = false;
zone3 = false;
zone4 = false;
z1label = z1;
z2label = z2;
z3label = z3;
z4label = z4;
}
}
MainPage.xaml.cs
private void AddGroup_Click(object sender, RoutedEventArgs e)
{
ZonesList_Panel.Children.Clear();
int groupid = 1;
int cardadr;
for (cardadr = 1; cardadr <= MAXCARDS; cardadr++)
{
var z4 = (4 * cardadr);
var z3 = (4 * cardadr) - 1;
var z2 = (4 * cardadr) - 2;
var z1 = (4 * cardadr) - 3;
DecoderGroupUserControl decoderGroupControl = new DecoderGroupUserControl(this, new DecoderGroup(groupid, cardadr, z1, z2, z3, z4));
ZonesList_Panel.Children.Add(decoderGroupControl);
}
}
private async void SaveGroup_Click(object sender, RoutedEventArgs e)
{
await saveGroupsToJSON(getGroups());
}
public async Task saveGroupsToJSON(List<DecoderGroup> groups)
{
var serializer = new DataContractJsonSerializer(typeof(List<DecoderGroup>));
using (var stream = await ApplicationData.Current.LocalFolder.OpenStreamForWriteAsync(DECODERGROUPS_FILE, CreationCollisionOption.OpenIfExists))
{
serializer.WriteObject(stream, groups);
}
}
public List<DecoderGroup> getGroups()
{
List<DecoderGroup> ret = new List<DecoderGroup>();
foreach (DecoderGroupUserControl u in ZonesList_Panel.Children)
{
//add condition for group ID
ret.Add(u.decoderGroup);
}
return ret;
}
UserControl
public DecoderGroupUserControl(MainPage page, DecoderGroup group)
{
this.InitializeComponent();
mainPage = page;
this.decoderGroup = group;
Z1Name.Text = group.z1label.ToString();
Z2Name.Text = group.z2label.ToString();
Z3Name.Text = group.z3label.ToString();
Z4Name.Text = group.z4label.ToString();
}
It is recommended to use UserControl as the DateTemplate of ListView so that you don’t need to create multiple usercontrol and add them to the page. Then you could read json file and convert json objects to a collection, and you could use the collection as the Itemsource of ListView.
By implementing the INotifyPropertyChanged interface, TwoWay data binding could reflect the UI changes to the collection. Finally, you could write the changed collection to the json file.
Note that you need to download the Newtonsoft.Json to parse the json object via Manage NuGet Packages. Please refer to the following code.
MyUserControl1.xaml:
<UserControl
..>
<Grid>
<!--customize the usercontrol style-->
<StackPanel>
<StackPanel Orientation="Horizontal" >
<TextBox Margin="0,0,20,0" Text="{Binding Name,Mode=TwoWay}" BorderThickness="0"/>
<TextBox Text="{Binding Job,Mode=TwoWay}" BorderThickness="0"/>
</StackPanel>
<TextBox Text="{Binding Age,Mode=TwoWay}" BorderThickness="0"/>
</StackPanel>
</Grid>
</UserControl>
MainPage.xaml:
<Page..>
<Grid>
<StackPanel>
<ListView ItemsSource="{x:Bind Results,Mode=TwoWay}">
<ListView.ItemTemplate>
<DataTemplate x:DataType="local:Person">
<local:MyUserControl1>
</local:MyUserControl1>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<Button x:Name="SaveButton" Content="Save" Click="SaveButton_Click"/>
</StackPanel>
</Grid>
</Page>
MainPage.xaml.cs:
namespace WriteJson
{
public sealed partial class MainPage : Page
{
public ObservableCollection<Person> Persons { get; set; }
public ObservableCollection<Person> Results { get; set; }
public string path;
public MainPage()
{
this.InitializeComponent();
CreateJsonFile();
path = ApplicationData.Current.LocalFolder.Path + "\\info.json";
Results = JsonConvert.DeserializeObject<ObservableCollection<Person>>(File.ReadAllText(path));
Debug.WriteLine("bind successfully");
}
public async void CreateJsonFile()
{
//check if info.json exists, if it doesn't exist, create it
StorageFolder folder = ApplicationData.Current.LocalFolder;
StorageFile file;
try
{
file = await folder.GetFileAsync("info.json");
}
catch
{
await folder.CreateFileAsync("info.json");
Persons = new ObservableCollection<Person>()
{
new Person(){Name="tom",Job="teacher",Age=24},
new Person(){Name="lily",Job="nurse",Age=20},
new Person(){Name="ming",Job="student",Age=26},
new Person(){Name="kiki",Job="lawyer",Age=28},
new Person(){Name="jack",Job="worker",Age=21},
};
path = ApplicationData.Current.LocalFolder.Path + "\\info.json";
File.WriteAllText(path, JsonConvert.SerializeObject(Persons));
Debug.WriteLine("create a json file successfully");
}
}
private void SaveButton_Click(object sender, RoutedEventArgs e)
{
File.WriteAllText(path, JsonConvert.SerializeObject(Results));
Debug.WriteLine("save successfully");
}
}
public class Person:INotifyPropertyChanged
{
private string name;
private string job;
private int age;
public string Name
{
get { return name; }
set
{
name = value;
RaisePropertyChanged("Name");
}
}
public string Job
{
get { return job; }
set
{
job = value;
RaisePropertyChanged("Job");
}
}
public int Age
{
get { return age; }
set
{
age = value;
RaisePropertyChanged("Age");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void RaisePropertyChanged(string propertyname=null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyname));
}
}
}

Xamarin Shell : Pass multiple arguments to another page

I have two pages in my Xamarin Forms Shell app.
One list page and another is the details page.
when I select the item in list page, the detail page will be shown. I was able to pass one parameter to the second page. I know how to pass the second value. But how should I receive the second value in the first property itself.
List Page:
async private void myLines_ItemTapped(object sender, ItemTappedEventArgs e)
{
var line = (Models.QLines)e.Item;
int pno = line.PageNo;
int lno = line.LineNo;
await Shell.Current.GoToAsync($"//mainTabs/pages?pageno={pno}&lineno={lno}");
}
Detail Page:
public int CurrentPage { get; set; }
public int CurrentLine { get; set; }
public bool IsFromSearchPage { get; set; }
public string PageNo
{
set
{
CurrentPage = Convert.ToInt32(Uri.UnescapeDataString(value));
IsFromSearchPage = true;
LoadPagesAsSingle();
}
}
public string LineNo
{
set
{
CurrentLine = Convert.ToInt32(Uri.UnescapeDataString(value));
}
}
public MyPages()
{
InitializeComponent();
conn = DependencyService.Get<ISQLiteMyConnection>().GetConnection();
IsFromSearchPage = false;
LoadPagesAsSingle();
}
As explained in https://learn.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/shell/navigation#pass-data you can use QueryProperty attribute to map between queryID and the target property:
[QueryProperty("Pageno", "pageno")]
[QueryProperty("Lineno", "lineno")]
public partial class DetailPage: ContentPage
{
private int _Pageno;
public int Pageno
{
get { return _Pageno; }
set { _Pageno = value; }
}
private int _Lineno;
public int Lineno
{
get { return _Lineno; }
set { _Lineno = value; }
}
As another solution you can pass parameters through static members of page. For example page may contain static ViewModel object, which will be initialized before page appears.
public class ViewModel : ViewModelBase
{
public string Text { get; set; }
public int Number { get; set; }
}
public class MyPage : Page
{
static ViewModel _viewModel = new ViewModel();
public MyPage()
{
BindingContext = _viewModel;
}
public static void InitPage(string text, int number)
{
_viewModel.Text = text;
_viewModel.Number = number;
}
}
}
Code inside caller
static async Task GotoPage()
{
MyPage.InitPage("Text", 123);
await Shell.Current.GoToAsync($"//mainTabs/pages");
}
you can use parameters in the detailPage
public DetailPage(string val1,string val2)
{
}
then call it in MyPage
Navigation.PushAsync(new DetailPage("parameter1","parameter2"));

Refresh datagrid when changes to database are made

I'm writing a wpf application, where I have music albums and corresponding songs. I can add albums and corresponding songs. But now I want to to refresh the view when a change to the database is made. I found many possible solutions, but as I'm new to wpf and c# I don't know which one would suite my code.
In my MainView have an album list and a add button which opens another window where I can add data with a textbox.
AlbumListViewModel
#region Constants
IWindowManager addAlbum = new WindowManager();
IWindowManager addSong = new WindowManager();
private AlbumViewModel _selectedAlbum;
private SongViewModel _selectedSong;
#endregion
#region Constructor
public AlbumListViewModel()
{
Albums = new ObservableCollection<AlbumViewModel>(GetAlbumList());
AddAlbumCommand = new RelayCommand(x => AddAlbum());
AddSongCommand = new RelayCommand(x => AddSong());
}
#endregion
#region Properties
public ICommand AddAlbumCommand { get; private set; }
public ICommand AddSongCommand { get; private set; }
public ObservableCollection<AlbumViewModel> Albums { get; set; }
public AlbumViewModel SelectedAlbum
{
get
{
return _selectedAlbum;
}
set
{
if (_selectedAlbum != value)
{
_selectedAlbum = value;
}
NotifyPropertyChanged("SelectedAlbum");
}
}
public SongViewModel SelectedSong
{
get
{
return _selectedSong;
}
set
{
if (_selectedSong != value)
{
_selectedSong = value;
}
NotifyPropertyChanged("SelectedSong");
}
}
#endregion
#region Methods
public List<AlbumViewModel> GetAlbumList()
{
var controller = new BandManagerController();
return controller.GetAlbumList()
.Select(a => new AlbumViewModel(a))
.ToList();
}
private void AddAlbum()
{
addAlbum.ShowDialog(new AlbumViewModel(new AlbumData()));
}
private void AddSong()
{
addSong.ShowDialog(new SongViewModel(new SongData { AlbumID = SelectedAlbum.AlbumID }));
}
It opens the AlbumView where I add albums to the database.
public class AlbumViewModel : Screen
{
#region Constants
private AlbumData _data;
#endregion
#region Constructor
public AlbumViewModel(AlbumData data)
{
_data = data;
SongListVM = new SongListViewModel(data.AlbumID);
SaveAlbumToDatabase = new RelayCommand(x => AlbumToDatabase(data));
}
#endregion
#region Properties
public SongListViewModel SongListVM { get; set; }
public ICommand SaveAlbumToDatabase { get; private set; }
public string AlbumName
{
get
{
return _data.AlbumName;
}
set
{
if (_data.AlbumName != value)
{
_data.AlbumName = value;
NotifyOfPropertyChange("AlbumName");
}
}
}
public int AlbumID
{
get
{
return _data.AlbumID;
}
set
{
if (_data.AlbumID != value)
{
_data.AlbumID = value;
NotifyOfPropertyChange("AlbumID");
}
}
}
public string AlbumYear
{
get
{
return _data.AlbumYear;
}
set
{
if (_data.AlbumYear != value)
{
_data.AlbumYear = value;
NotifyOfPropertyChange("AlbumYear");
}
}
}
#endregion
#region Methods
public AlbumData AddAlbumEntry(AlbumData albumData)
{
var controller = new BandManagerController();
return controller.AddAlbumEntry(albumData);
}
public void ExecuteCancelCommand()
{
(GetView() as Window).Close();
}
public void AlbumToDatabase(AlbumData data)
{
AddAlbumEntry(data);
ExecuteCancelCommand();
}
#endregion
}
The AddAlbumEntry Method in the ALbumView is in a different class which is the connections to my database. I already use an ObservableCollection but don't know how to tell it the Database was updated.
Thanks in advance!
Just want to answer my question. I just changed my AddAlbum method to use a Deactivated event, to reload the Collection after the Dialog closes like:
private void AddAlbum()
{
var vm = new AlbumViewModel(new AlbumData());
vm.Deactivated += (s, e) => GetAlbumList();
addAlbum.ShowDialog(vm);
}

Telerik RadComboBox WPF How to display list of values from database table?

I'm using MVVM with WPF and have a RadComboBox in my view that needs to be populated from my County table in my database. My viewmodel is as follows:
public class AddClientViewModel : BindableBase
{
private Client _client;
private Circuit _circuit;
private County _county;
private State _state;
private SubscriberSpecialty _subscriberSpecialty;
private IClientsRepository _repository = new ClientRepository();
private ICircuitRepository _circuitRepository = new CircuitRepository();
private ICountyRepository _countyRepository = new CountyRepository();
private IStateRepository _stateRepository = new StateRepository();
private ISubscriberSpecialty _subscriberSpecialtyRepository = new SubscriberSpecialtyRepository();
public AddClientViewModel()
{
SaveCommand = new RelayCommand(OnSave);
}
public event PropertyChangedEventHandler PropertyChanged = delegate { };
public Client Client
{
get { return _client; }
set
{
if (value != _client)
{
_client = value;
PropertyChanged(this, new PropertyChangedEventArgs("Client"));
}
}
}
public Circuit Circuit
{
get { return _circuit; }
set
{
if(value != _circuit)
{
_circuit = value;
PropertyChanged(this, new PropertyChangedEventArgs("Circuit"));
}
}
}
public County County
{
get { return _county;}
set
{
if (value != _county)
{
_county = value;
PropertyChanged(this, new PropertyChangedEventArgs("County"));
}
}
}
public State State
{
get { return _state; }
set
{
if (value != _state)
{
_state = value;
PropertyChanged(this, new PropertyChangedEventArgs("State"));
}
}
}
public SubscriberSpecialty SubscriberSpecialty
{
get { return _subscriberSpecialty; }
set
{
if (value != _subscriberSpecialty)
{
_subscriberSpecialty = value;
PropertyChanged(this, new PropertyChangedEventArgs("SubscriberSpecialty"));
}
}
}
public Guid ClientId { get; set; }
public Guid CircuitId { get; set; }
public Guid CountyId { get; set; }
public Guid StateId { get; set; }
public Guid SubscriberSpecialtyId { get; set; }
public ICommand SaveCommand { get; set; }
public event Action<Client> AddClient = delegate { };
public async void LoadClient()
{
Client = await _repository.GetClientAsync(ClientId);
}
public async void LoadCircuit()
{
Circuit = await _circuitRepository.GetCircuitAsync(CircuitId);
}
public async void LoadCounty()
{
County = await _countyRepository.GetCountyAsync(CountyId);
}
public async void LoadState()
{
State = await _stateRepository.GetStateAsync(StateId);
}
public async void LoadSubscriberSpecialty()
{
SubscriberSpecialty = await _subscriberSpecialtyRepository.GetSubscriberSpecialtyAsync(SubscriberSpecialtyId);
}
private void OnAddClient()
{
AddClient(new Client {ClientId = Guid.NewGuid()});
}
private async void OnSave()
{
try
{
Client = await _repository.AddClientAsync(new Client());
}
catch (Exception ex)
{
MessageBox.Show("A handled exception just occurred: " + ex.Message, "Exception", MessageBoxButton.OK,
MessageBoxImage.Warning);
}
}
}
The interface has the following:
Task<County> GetCountyAsync(Guid countyId);
The repository class calls the interface as:
public Task<List<County>> GetCountiesAsync()
{
return _context.Counties.ToListAsync();
}
My view then uses the following syntax:
<telerik:RadComboBox x:Name="Countycombo"
Grid.Column="1" Grid.Row="3"
ItemsSource="{Binding County.CountyName}"
DisplayMemberPath="CountyName" Width="120"/>
I defined a DataContext in the layout as follows:
<UserControl.DataContext>
<viewModels:AddClientViewModel />
</UserControl.DataContext>
When I run the application, the RadComboBox doesn't grab the values from the County table, into which I've loaded several values for CountyName. How do I correct the above code snippets to ensure my County Names are populated?
Update: When I remove County from County.CountyName, I receive the message stating Cannot resolve property CountyName in DataContext MySolution.ViewModels.MyViewModel What additional work is needed in the viewmodel either in LoadCounty or other sections?
I would suggest the following:
Introduce the ViewModel property that will hold a list of County objects:
private List<County> _counties;
public List<County> Counties
{
get { return _counties;}
set
{
if (value != _counties)
{
_counties = value;
PropertyChanged(this, new PropertyChangedEventArgs("Counties"));
}
}
}
Bind a ComboBox ItemsSource to the Counties property, and a ComboBox SelectedItem property to the County property.
<telerik:RadComboBox x:Name="Countycombo"
Grid.Column="1" Grid.Row="3"
ItemsSource="{Binding Counties}"
SelectedItem="{Binding County}"
DisplayMemberPath="CountyName" Width="120"/>
And you need to a place where you will load the counties with a repository call to a GetCountiesAsync. The result should be set to the ViewModel Counties property.
public async void LoadCounties()
{
Counties = await _countyRepository.GetCountiesAsync();
}
Not sure what is the best place to make that call.

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