I write new WPF MVVM app.
I new in WPF.
I have problem with binding value to StageControl from MainPageModelView.
StageControl is in MainPage.
I know how binding value to element in MainPage, but I can't binding value to StageControl in this same way.
How can I binding value from MainPageModelView to StageControl?
Code:
MainPage.xaml
<my:StageControl x:Name="stageControl1" StageIsActive="true" StageName="{Binding Stage.Name}" Grid.Row="0" Grid.Column="0"/>
...
<Label x:Name="lbTest" Content="{Binding Test}" HorizontalAlignment="Left" Margin="104,10,0,0" VerticalAlignment="Top" Height="56" Width="68"/>
StageControl.xaml.cs
public partial class StageControl : UserControl
{
string stageName;
bool stageIsActive;
public StageControl()
{
InitializeComponent();
}
public bool StageIsActive
{
get { return this.stageIsActive; }
set { this.stageIsActive = SetStageControlStatus(value); }
}
public string StageName
{
get { return this.stageName; }
set { this.stageName = SetStageName(value); }
}
private bool SetStageControlStatus(bool value)
{
if (value)
{
this.outRing.Visibility = Visibility.Visible;
return true;
}
else
{
this.outRing.Visibility = Visibility.Hidden;
return false;
}
}
private string SetStageName(string value)
{
this.text.Text = value;
return this.text.Text;
}
}
MainPageViewModel.cs
class MainPageViewModel
{
public List<Stage> Stages = new List<Stage>();
public Stage stage = new Stage(0, "Test", true);
public MainPageViewModel()
{
Stages = Stage.GetStages();
}
public string Test
{
get { return "Testowy Label"; }
set { }
}
}
Edit:
MainPage.xaml.css
public MainPage()
{
InitializeComponent();
MainPageViewModel viewModel = new MainPageViewModel();
this.DataContext = viewModel;
}
I solved the problem.
First I add dependency property to StageControl.xaml.cs, then I add binding to StageControl.xaml
...
x:Name="Stage"
...
<TextBlock x:Name="text" TextWrapping="Wrap" Text="{Binding ElementName=Stage, Path=StageName}" TextAlignment="Center" FontSize="12" HorizontalAlignment="Center" VerticalAlignment="Center"/>
public Stage Stage {get;set;} = new Stage(0,"Test",true);
u need to make property instead of public variable
Related
I have a Parent ViewModel which contains a child view model object inside with some enum,
When I open the UI I see that the enum value not renders as expected from the RaisePropertyChanged event on first time loading, however, after setting a value from the UI the value changes and renders as expected.
Parent VM xaml
<UserControl x:Class="RemoteDebugger.App.Views.ConfigurationControl"
d:DataContext="{d:DesignInstance viewModels:ConfigurationViewModel}">
<Grid>
//Some properties...
<local:ProjectEditor Grid.Row="5" Grid.Column="1" BorderBrush="#FFCFCBCB" BorderThickness="0,1,0,1" Grid.ColumnSpan="3" DataContext="{Binding MainProject,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" ></local:ProjectEditor>
</Grid>
Parent VM cs
using RemoteDebugger.App.Utils;
using System.Collections.Generic;
using System.IO;
using System.Windows.Input;
using Microsoft.Win32;
using RemoteDebugger.Model;
using RemoteDebugger.Model.DataStructures;
namespace RemoteDebugger.App.ViewModels
{
public class ConfigurationViewModel : BaseViewModel
{
private ICommand _saveConfiguration;
private ICommand _loadConfiguration;
private Configuration _configuration;
private ProjectViewModel _mainProject;
private ExtraProjectsViewModel _extraProjects;
public ConfigurationViewModel()
{
_configuration = RemoteDebuggerManager.Instance.Configuration;
_mainProject = new ProjectViewModel(_configuration.MainProject);
_extraProjects = new ExtraProjectsViewModel(_configuration.ExtraProjectsToCopy);
}
public ICommand SaveConfiguration
{
get
{
return _saveConfiguration ??= new Command(o =>
{
_configuration.MainProject = _mainProject.Project;
_configuration.ExtraProjectsToCopy = _extraProjects.Projects;
RemoteDebuggerManager.Instance.SaveConfigurations();
});
}
}
public ICommand LoadConfiguration
{
get
{
return _loadConfiguration ??= new Command(o =>
{
var fd = new OpenFileDialog
{
Multiselect = false,
Filter = "XML Files (*.xml)|*.xml",
InitialDirectory = ConfigurationHandler.ConfigurationFolder
};
var path = fd.ShowDialog();
if (path == null || !File.Exists(fd.FileName))
return;
_configuration = RemoteDebuggerManager.Instance.LoadConfigurations(fd.FileName);
UpdateView();
});
}
}
private void UpdateView()
{
OsBits = _configuration.OsBits;
VisualStudioVersion = _configuration.VisualStudioVersion;
CopyExtraPaths = _configuration.CopyExtraPaths;
Ip = _configuration.ControllerIp;
_mainProject.Project = _configuration.MainProject;
_extraProjects.Projects = _configuration.ExtraProjectsToCopy;
}
public string VisualStudioVersion
{
get => _configuration.VisualStudioVersion;
set
{
_configuration.VisualStudioVersion = value;
RaisePropertyChanged(nameof(VisualStudioVersion));
}
}
public string OsBits
{
get => _configuration.OsBits;
set
{
_configuration.OsBits = value;
RaisePropertyChanged(nameof(OsBits));
}
}
public string Ip
{
get => _configuration.ControllerIp;
set
{
_configuration.ControllerIp = value;
RaisePropertyChanged(nameof(Ip));
}
}
public string WaitForDebugFileDestination
{
get => _configuration.WaitForDebugFileDestination;
set
{
_configuration.WaitForDebugFileDestination = value;
RaisePropertyChanged(nameof(WaitForDebugFileDestination));
}
}
public bool CopyExtraPaths
{
get => _configuration.CopyExtraPaths;
set
{
_configuration.CopyExtraPaths = value;
RaisePropertyChanged(nameof(CopyExtraPaths));
}
}
public ProjectViewModel MainProject
{
get => _mainProject;
set
{
_mainProject = value;
RaisePropertyChanged(nameof(MainProject));
}
}
public ExtraProjectsViewModel ExtraProjects
{
get => _extraProjects;
set
{
_extraProjects = value;
RaisePropertyChanged(nameof(ExtraProjects));
}
}
public List<string> VisualStudioSupportedVersions => EnvironmentValues.VisualStudioVersions;
public List<string> OsBitsTypes => EnvironmentValues.OsBits;
}
}
Child VM xaml
<UserControl x:Class="RemoteDebugger.App.Views.ProjectEditor"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:viewModels="clr-namespace:RemoteDebugger.App.ViewModels"
xmlns:local="clr-namespace:RemoteDebugger.App.Views"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance viewModels:ProjectViewModel}"
>
<Grid>
<Grid.RowDefinitions>
...
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
...
</Grid.ColumnDefinitions>
<ComboBox Grid.Row ="1" Grid.Column="1" ItemsSource="{Binding ProjectTypes}" VerticalAlignment="Center" SelectedItem="{Binding ProjectType,UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" FontSize="14" />
<TextBlock Grid.Row ="1" Grid.Column="0" Text="Project type" TextWrapping="Wrap"/>
<TextBlock Grid.Row ="5" Grid.Column="0" Text="Local project path" VerticalAlignment="Center" TextWrapping="Wrap"/>
<TextBox Grid.Row ="5" Grid.Column="1" Height="30" Text="{Binding LocalDllDirRoot,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />
<TextBlock Grid.Row ="7" Grid.Column="0" Text="Remote project path" VerticalAlignment="Center" TextWrapping="Wrap"/>
<TextBox Grid.Row ="7" Grid.Column="1" Height="30" Text="{Binding RemoteDllDirRoot,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />
<TextBlock Grid.Row ="9" Grid.Column="0" Text="Arguments" VerticalAlignment="Center" TextWrapping="Wrap"/>
<TextBox Grid.Row ="9" Grid.Column="1" Height="30" Text="{Binding Arguments,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />
<TextBlock Grid.Row ="3" Grid.Column="0" Text="Executable name" VerticalAlignment="Center" TextWrapping="Wrap"/>
<TextBox Grid.Row ="3" Grid.Column="1" Height="30" Text="{Binding ExecutableName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />
</Grid>
Child VM cs file
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using IntelGenericUIFramework.Common;
using RemoteDebugger.Model.DataStructures;
namespace RemoteDebugger.App.ViewModels
{
public class ProjectViewModel : BaseViewModel,ICloneable
{
private ProjectDescriptor _project;
public ProjectViewModel()
{
_project = new ProjectDescriptor();
}
public ProjectViewModel(ProjectDescriptor projectDescriptor)
{
_project = projectDescriptor == null ? new ProjectDescriptor() :
(ProjectDescriptor)projectDescriptor.Clone() ;
UpdateProperties();
}
private void UpdateProperties()
{
foreach (var prop in this.GetType().GetProperties())
{
RaisePropertyChanged(nameof(prop.Name));
}
}
#region Main project values
public string LocalDllDirRoot
{
get => _project.LocalDllDirRoot;
set
{
Project.LocalDllDirRoot = value;
RaisePropertyChanged(nameof(LocalDllDirRoot));
RaisePropertyChanged(nameof(Project));
}
}
public string RemoteDllDirRoot
{
get => _project.RemoteDllDirRoot;
set
{
_project.RemoteDllDirRoot = value;
RaisePropertyChanged(nameof(RemoteDllDirRoot));
RaisePropertyChanged(nameof(Project));
}
}
public string ExecutableName
{
get => Project.ExecutableName;
set
{
_project.ExecutableName = value;
RaisePropertyChanged(nameof(ExecutableName));
RaisePropertyChanged(nameof(Project));
}
}
public string Arguments
{
get => Project.Arguments;
set
{
_project.Arguments = value;
RaisePropertyChanged(nameof(Arguments));
RaisePropertyChanged(nameof(Project));
}
}
public bool IsService
{
get => Project.IsService;
set
{
_project.IsService = value;
RaisePropertyChanged(nameof(IsService));
RaisePropertyChanged(nameof(Project));
}
}
public ProjectType ProjectType
{
get => Project.ProjectType;
set
{
_project.ProjectType = value;
RaisePropertyChanged(nameof(ProjectType));
RaisePropertyChanged(nameof(Project));
}
}
#endregion
public void Clear()
{
LocalDllDirRoot = string.Empty;
RemoteDllDirRoot = string.Empty;
ExecutableName = string.Empty;
IsService = false;
Arguments = string.Empty;
ProjectType = ProjectType.None;
}
public ProjectDescriptor Project
{
get => _project;
set
{
if (value == null)
return;
_project = (ProjectDescriptor)value.Clone();
UpdateProperties();
}
}
public object Clone()
{
return Project.Clone();
}
public List<string> ProjectTypes => Enum.GetNames(typeof(ProjectType)).ToList();
}
}
Example of the broken binding
the marked field not loading the correct selected enum value and show a blank selection, while the other properties are shown as expected.
The problem is that 'ProjectType' property in Child VM cs file
not renders on startup in UI in Parent VM xaml
Thanks ahead!
ProjectTypes is a List<string> and ProjectType is a ProjectType.
The types should match so either change the type of the source collection:
public List<ProjectType> ProjectTypes =>
Enum.GetValues(typeof(ProjectType)).OfType<ProjectType>().ToList();
...or the type of the SelectedItem source property to string.
I am relatively new to MVVM and I want to bind my view to the view model. I have a lot of code to move from the CodeBehind into the ViewModel class.
What I would like to do is binding the ComboBox Events to the corresponding ViewModel ICommand methods. I want the ComboBox to show "CompanyB" when the view loads and when I make a selection, the ComboBox should give me "CompanyA", "CompanyB" and "CompanyC" as options to select from.
After a company was selected, the values of the 2 textboxes below
Nachbest.Empf_Ansprechpartner
Nachbest.Empfaenger_Mail
must change accordingly.
The problem is with my code both the ComboBox and the textboxes remain empty and there is also nothing to choose from inside the combobox.
Could you please help me find what I am missing here? Thanks in advance for any help!
XAML (neueNachbestellung.xaml):
<Window xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity">
<Grid>
<StackPanel Grid.Column="0" Margin="25,25,0,0" x:Name="leftStPnl">
<ComboBox x:Name="cboxEmpfaenger"
ItemsSource="{Binding Empf}"
Text="{Binding Empfaenger}"
FontSize="12" Width="150" Margin="118,0,0,0"
SelectedItem="{Binding SelValue}">
</ComboBox>
<TextBox x:Name="txtEmpfAnsprechpartner" Text="{Binding Empf_Ansprechpartner}" FontSize="12" IsEnabled="False" Width="150" Margin="50,0,0,0"/>
<TextBox x:Name="txtEmpfMail" Text="{Binding Empfaenger_Mail}" FontSize="12" IsEnabled="False" Width="150" Margin="73,0,0,0"/>
</StackPanel>
</Grid>
</Window>
Code Behind (neueNachbestellung.xaml.cs):
public neueNachbestellung(string someId)
{
InitializeComponent();
this.DataContext = new neueNachbestellungViewModel(someId);
}
View Model(neueNachbestellungViewModel.cs):
public class neueNachbestellungViewModel: INotifyPropertyChanged
{
public ICommand LoadCombobox => new DelegateCommand<object>(ExecuteLoadCombobox);
public ICommand ComboboxSelectionChanged => new DelegateCommand<object>(ExecuteComboboxSelectionChanged);
public Nachbestellung Nachbest { get; set; }
private object someObject;
private ObservableCollection<string> _empf;
public ObservableCollection<string> Empf
{
get { return _empf; }
set
{
_empf = value;
OnPropertyChanged("Empf");
}
}
private string _selValue = "12";
public string SelValue
{
get { return _selValue; }
set
{
_selValue = value;
OnPropertyChanged("SelValue");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public virtual void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
public neueNachbestellungViewModel(string id)
{
this.Artikel = new ArtikelViewModel();
this.ArtikelList = new ObservableCollection<Artikel>();
InitializeReorderModel(id);
ExecuteComboboxSelectionChanged(someObject);
}
public void InitializeReorderModel(string id)
{
//set the MODEL
this.Nachbest = new Nachbestellung();
//Retrieve and set some values on *VIEW LOAD*!
var dbOracle = new Datenbank();
this.Nachbest.Bv = dbOracle.GetBauvorhaben(hv);
this.Nachbest.Hv = hv;
this.Nachbest.Bauleiter = dbOracle.GetBauleiter(hv);
this.Nachbest.Projektleiter = dbOracle.GetProjektleiter(hv);
}
private void ExecuteLoadCombobox(object param)
{
Empf = new ObservableCollection<string>()
{
"CompanyA",
"CompanyB",
"CompanyC"
};
//Company B is the standard selection on combobox load
Nachbest.Empf_Ansprechpartner = "CompanyB";
Nachbest.Empfaenger_Mail = "orders#companyB.com";
}
private void ExecuteComboboxSelectionChanged(object param)
{
Empf = new ObservableCollection<string>()
{
"CompanyA",
"CompanyB",
"CompanyC"
};
switch (SelValue)
{
case "CompanyA":
{
Nachbest.Empf_Ansprechpartner = "CompanyA";
Nachbest.Empfaenger_Mail = "service#companyA.com";
}
break;
case "CompanyB":
{
Nachbest.Empf_Ansprechpartner = "CompanyB";
Nachbest.Empfaenger_Mail = "orders#companyB.com";
}
break;
case "CompanyC":
{
Nachbest.Empf_Ansprechpartner = "CompanyC";
Nachbest.Empfaenger_Mail = "info#companyC.com";
}
break;
default:
MessageBox.Show("Something went wrong with the company selection!");
break;
}
}
}
View Fragment:
This is my quick & dirty solution. It does what it needs to and I don't have these click_button, selection_changed events inside my code behind anymore but inside my view model. That is all I need for now. Obviously not an elegant solution but it is working. I hope I can help some developers with it in the future who run into similar problems. Just a side note: The ICommand properties inside the view model are not necessary in this scenario but I am using them to handle button click events in the view. You can replace them with your own properties if you don't need the DelegateCommand class in your application.
XAML (neueNachbestellung.xaml):
<Window>
<Grid>
<StackPanel Grid.Column="0" Margin="25,25,0,0" x:Name="leftStPnl">
<ComboBox x:Name="cboxEmpfaenger"
ItemsSource="{Binding Empf}"
Text="{Binding Empfaenger}"
FontSize="12" Width="150" Margin="118,0,0,0"
SelectedItem="{Binding SelValue}">
</ComboBox>
<TextBox x:Name="txtEmpfAnsprechpartner" DataContext="{Binding Nachbest}" Text="{Binding Empf_Ansprechpartner}" FontSize="12" IsEnabled="False" Width="150" Margin="50,0,0,0"/>
<TextBox x:Name="txtEmpfMail" DataContext="{Binding Nachbest}" Text="{Binding Empfaenger_Mail}" FontSize="12" IsEnabled="False" Width="150" Margin="73,0,0,0"/>
</StackPanel>
</Grid>
</Window>
Code Behind (neueNachbestellung.xaml.cs):
public neueNachbestellung(string someId)
{
InitializeComponent();
this.DataContext = new neueNachbestellungViewModel(someId);
}
neueNachbestellungViewModel.cs:
public class neueNachbestellungViewModel: INotifyPropertyChanged
{
//public ICommand LoadCombobox => new DelegateCommand<object>(ExecuteLoadCombobox);
public ICommand ComboboxSelectionChanged => new DelegateCommand<object>(ExecuteComboboxSelectionChanged);
public Nachbestellung Nachbest { get; set; }
private object someObject; //DelegateCommand.cs requires an argument
private ObservableCollection<string> _empf;
public ObservableCollection<string> Empf
{
get { return _empf; }
set
{
_empf = value;
OnPropertyChanged("Empf");
}
}
private string _selValue = "CompanyB"; //default value
public string SelValue
{
get { return _selValue; }
set
{
_selValue = value;
OnPropertyChanged("SelValue");
switch (SelValue)
{
case "CompanyA":
{
Nachbest.Empf_Ansprechpartner = "CompanyA";
Nachbest.Empfaenger_Mail = "service#companyA.com";
}
break;
case "CompanyB":
{
Nachbest.Empf_Ansprechpartner = "CompanyB";
Nachbest.Empfaenger_Mail = "orders#companyB.com";
}
break;
case "CompanyC":
{
Nachbest.Empf_Ansprechpartner = "CompanyC";
Nachbest.Empfaenger_Mail = "info#companyC.com";
}
break;
default:
MessageBox.Show("Something went wrong with the company selection!");
break;
}
//setting the Empfaenger property here with the current selected value is necessary for the database insert later on!
Nachbest.Empfaenger = SelValue;
}
}
public event PropertyChangedEventHandler PropertyChanged;
public virtual void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
public neueNachbestellungViewModel(string id)
{
this.Artikel = new ArtikelViewModel();
this.ArtikelList = new ObservableCollection<Artikel>();
InitializeReorderModel(id);
ExecuteComboboxSelectionChanged(someObject);
}
public void InitializeReorderModel(string id)
{
//set the MODEL
this.Nachbest = new Nachbestellung();
//Retrieve and set some values on *VIEW LOAD*!
var dbOracle = new Datenbank();
this.Nachbest.Bv = dbOracle.GetBauvorhaben(hv);
this.Nachbest.Hv = hv;
this.Nachbest.Bauleiter = dbOracle.GetBauleiter(hv);
this.Nachbest.Projektleiter = dbOracle.GetProjektleiter(hv);
}
private void ExecuteComboboxSelectionChanged(object param)
{
Empf = new ObservableCollection<string>()
{
"CompanyA",
"CompanyB",
"CompanyC"
};
Nachbest.Empf_Ansprechpartner = "CompanyB";
Nachbest.Empfaenger_Mail = "orders#companyB.com";
Nachbest.Empfaenger = SelValue; //if this is left out and there is no selection (just the default remaining unchanged!), Nachbest.Empfaenger will be null!
}
}
I'm just getting used to MVVM and want to do without the code-behind and define everything in the view-models.
the combobox represents several selection options (works). I would like to query the elements that have been checked.
Unfortunately I can't access them. The textbox should display all selected elements as concatenated string.
View-Model
class MainViewModel : BaseViewModel
{
#region Fields
private ObservableCollection<EssayTypeViewModel> _essayTypes;
private EssayTypeViewModel _selectedEssayTypes;
#endregion
public ObservableCollection<EssayTypeViewModel> EssayTypes
{
get => _essayTypes;
set
{
if (_essayTypes == value) return;
_essayTypes = value; OnPropertyChanged("EssayTypes");
}
}
public EssayTypeViewModel SelectedEssayTypes
{
get => _selectedEssayTypes;
set { _selectedEssayTypes = value; OnPropertyChanged("SelectedEssayTypes"); }
}
public MainViewModel()
{
// Load Essay Types
EssayTypeRepository essayTypeRepository = new EssayTypeRepository();
var essayTypes = essayTypeRepository.GetEssayTypes();
var essayTypeViewModels = essayTypes.Select(m => new EssayTypeViewModel()
{
Text = m.Text
});
EssayTypes = new ObservableCollection<EssayTypeViewModel>(essayTypeViewModels);
}
}
XAML
<ListBox x:Name="Listitems" SelectionMode="Multiple" Height="75" Width="200" ItemsSource="{Binding EssayTypes}" >
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Content="{Binding Text}" IsChecked="{Binding Checked}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<TextBox Text="{Binding Path=SelectedEssayTypes}" Grid.Column="0" Width="160" Height="25" Margin="0,140,0,0"/>
You could hook up an event handler to the PropertyChanged event of all EssayTypeViewModel objects in the EssayTypes collection and raise the PropertyChanged event for a read-only property of the MainViewModel that returns all selected elements as concatenated string:
public MainViewModel()
{
// Load Essay Types
EssayTypeRepository essayTypeRepository = new EssayTypeRepository();
var essayTypes = essayTypeRepository.GetEssayTypes();
var essayTypeViewModels = essayTypes.Select(m =>
{
var vm = EssayTypeViewModel()
{
Text = m.Text
};
vm.PropertyChanged += OnPropertyChanged;
return vm;
});
EssayTypes = new ObservableCollection<EssayTypeViewModel>(essayTypeViewModels);
}
private void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == "Checked")
OnPropertyChanged("SelectedItems");
}
public string SelectedItems => string.Join(",", EssayTypes.Where(x => x.Checked).ToArray());
This requires the EssayTypeViewModel class to implement the INotifyPropertyChanged interface (by for example deriving from your BaseViewModel class).
You can apply Mode = Two way on the checkbox binding.
<CheckBox Content="{Binding Text}" IsChecked="{Binding Checked, Mode=TwoWay}"/>
then you can iterate through the essay types collection to check if the item entry was checked.
For ex. Sample code can be:
foreach (var essayTypeInstance in EssayTypes)
{
if(essayTypeInstance.Checked)
{
// this value is selected
}
}
Hope this helps.
mm8 answer works. In the meantime i came up with another approach. Not 100% MVVM compatible but it works and is quite simple.
XAML
<ListBox x:Name="ListItems" SelectionMode="Multiple" Height="75" Width="200" ItemsSource="{Binding CollectionOfItems}" >
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Content="{Binding Name}" IsChecked="{Binding Checked, Mode=TwoWay}" Unchecked="GetCheckedElements" Checked="GetCheckedElements" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<TextBox Text="{Binding SelectedItemsString, UpdateSourceTrigger=PropertyChanged}" Grid.Column="0" Width="160" Height="25" Margin="0,140,0,0"/>
Code Behind
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
}
private void GetCheckedElements(object sender, RoutedEventArgs e)
{
(DataContext as MainViewModel)?.FindCheckedItems();
(DataContext as MainViewModel)?.ConcatSelectedElements();
}
}
Model
public class Items
{
public bool Checked { get; set; }
public string Name { get; set; }
}
ItemsViewModel (BaseViewModel only implements INotifyPropertyChanged)
class ItemsViewModel : BaseViewModel
{
private bool _checked;
private string _name;
public bool Checked
{
get => _checked;
set
{
if (value == _checked) return;
_checked = value;
OnPropertyChanged("Checked");
}
}
public string Name
{
get => _name;
set
{
if (value == _name) return;
_name = value;
OnPropertyChanged("Name");
}
}
}
MainViewModel
public class MainViewModel : BaseViewModel
{
private string _selectedItemsString;
private ObservableCollection<Items> _selectedItems;
public ObservableCollection<Items> CollectionOfItems { get; set; }
public ObservableCollection<Items> SelectedItems
{
get => _selectedItems;
set
{
_selectedItems = value;
OnPropertyChanged("SelectedItems");
}
}
public string SelectedItemsString
{
get => _selectedItemsString;
set
{
if (value == _selectedItemsString) return;
_selectedItemsString = value;
OnPropertyChanged("SelectedItemsString");
}
}
public MainViewModel()
{
CollectionOfItems = new ObservableCollection<Items>();
SelectedItems = new ObservableCollection<Items>();
CollectionOfItems.Add(new Items { Checked = false, Name = "Item 1" });
CollectionOfItems.Add(new Items { Checked = false, Name = "Item 2" });
CollectionOfItems.Add(new Items { Checked = false, Name = "Item 3" });
}
public void FindCheckedItems()
{
CollectionOfItems.Where(x => x.Checked).ToList().ForEach(y => SelectedItems.Add(y));
}
public void ConcatSelectedElements()
{
SelectedItemsString = string.Join(", ", CollectionOfItems.Where(x => x.Checked).ToList().Select(x => x.Name)).Trim();
}
}
I am trying to use Prism in a C# to but I seem to have set it up so that it binds to items in my model and not my viewmodel. It is a short program that is more of a learning tool that anything. When I move the items to the Viewmodel the SetProperty's don't seem to notify the view of the change.
Any thoughts as to how I have this setup backwards?
Model:
namespace XMLValueModifier_Threaded_WPF.Models
{
public class XMLReadFileModel : BindableBase
{
private string _XMLMasterFile2 = "0";
public string XMLGetFileName()
{
if (_XMLMasterFile2 != "1")
{
Microsoft.Win32.OpenFileDialog _XMLMasterFileDialog = new Microsoft.Win32.OpenFileDialog();
_XMLMasterFileDialog.DefaultExt = "xml";
_XMLMasterFileDialog.Filter = "xml Files (*.xml; *.XML) | *.xml; *.XML";
Nullable<bool> result = _XMLMasterFileDialog.ShowDialog();
if (result == true)
{
return _XMLMasterFileDialog.FileName;
}
return "";
}
else
{
return "";
}
}
}
}
ViewModel:
namespace XMLValueModifier_Threaded_WPF.ViewModels
{
public class MainDialogueViewModel : BindableBase
{
private string _XMLMasterFile;
public ICommand MasterFileLocation
{
get;
set;
}
public ICommand XMLFileLocation
{
get;
set;
}
public string XMLMasterFile
{
get
{
return _XMLMasterFile;
}
set
{
SetProperty(ref _XMLMasterFile, value);
}
}
private XMLReadFileModel xmlReadFileModel = new XMLReadFileModel();
public MainDialogueViewModel()
{
XMLReadFileModel xmlReadFileModel = new XMLReadFileModel();
Message = "example message";
XMLMasterFile = "example File";
this.MasterFileLocation = new DelegateCommand(chooseFile, canChooseFile);
this.XMLFileLocation = new DelegateCommand(chooseFile, canChooseFile);
}
public void masterfilelocation()
{
MessageBox.Show("i am here");
return;
}
private void chooseFile()
{
XMLMasterFile = xmlReadFileModel.XMLGetFileName();
}
private bool canChooseFile()
{
if (XMLMasterFile != null)
{
return true;
}
else
{
return true;
}
}
}
}
XAML:
<Window x:Class="XMLValueModifier_Threaded_WPF.Views.MainDialogue"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:XMLValueModifier_Threaded_WPF.ViewModels" Width="625" Height="452"
>
<Grid Margin="0,-24,0,-3">
<TextBox x:Name="Textbox1" Text="{Binding MainDialogueViewModel.XMLMasterFile,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Height="23" Margin="25,120,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="425"/>
<TextBox x:Name="Textbox2" Text="{Binding MainDialogueViewModel.XMLFiles,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Height="23" Margin="25,188,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="425" RenderTransformOrigin="0.506,1.565"/>
<Label Content="Location of Master XML File" HorizontalAlignment="Left" Margin="25,89,0,0" VerticalAlignment="Top"/>
<Label Content="Location of XML File(s)" HorizontalAlignment="Left" Margin="25,157,0,0" VerticalAlignment="Top"/></GRID>
Assuming you have your DataContext setup correctly to an instance of MainDialogueViewModel; you don't need to include MainDialogueViewModel in your binding. Simply bind to the property name XMLMasterFile. Also keep in mind that if the value isn't different, then nothing will be updated.
I am just starting with MVVM and have hit a hurdle that I hope someone can help me with. I am trying to create a simple View with 2 listboxes. A selection from the first listbox will populate the second list box. I have a class created that stores the information I want to bind to.
MyObject Class (Observable Object is just a base class that implements INotifyPopertyChanged)
public class MyObject : ObservableObject
{
String _name = String.Empty;
ObservableCollection<MyObject> _subcategories;
public ObservableCollection<MyObject> SubCategories
{
get { return _subcategories; }
set
{
_subcategories = value;
RaisePropertyChanged("SubCategories");
}
}
public String Name
{
get { return _name; }
set
{
_name = value;
RaisePropertyChanged("Name");
}
}
public MyObject()
{
_subcategories = new ObservableCollection<EMSMenuItem>();
}
}
In my viewmodel I have two ObservableCollections created
public ObservableCollection<EMSMenuItem> Level1MenuItems { get; set; }
public ObservableCollection<EMSMenuItem> Level2MenuItems { get; set; }
In my constructor of the ViewModel I have:
this.Level1MenuItems = new ObservableCollection<EMSMenuItem>();
this.Level2MenuItems = new ObservableCollection<EMSMenuItem>();
this.Level1MenuItems = LoadEMSMenuItems("Sample.Xml");
That works fine for the Level1 items and they correctly show in the View. However I have a command that gets called when the user clicks an item in the listbox, which has the following:
Level2MenuItems = ClickedItem.SubCategories;
For some reason this does not update the UI of the second listbox. If I put a breakpoint at this location I can see that Level2MenuItems has the correct information stored in it. If I write a foreach loop and add them individually to the Level2MenuItems collection then it does display correctly.
Also as a test I added the following to the constructor:
Level2MenuItems = Level1MenuItems[0].SubCategories;
And that updated correctly.
So why would the code work as expected in the constructor, or when looping through, but not when a user clicks on an item in the listbox?
You need to raise the change notification on the Level2MenuItems property.
Instead of having
public ObservableCollection<EMSMenuItem> Level2MenuItems { get; set; }
you need
private ObservableCollection<EMSMenuItem> _level2MenuItems;
public ObservableCollection<EMSMenuItem> Level2MenuItems
{
get { return _level2MenuItems; }
set
{
_level2MenuItems = value;
RaisePropertyChanged(nameof(Level2MenuItems));
}
}
The reason the former works in the constructor is that the Binding has not taken place yet. However since you are changing the reference via a command execute which happens after the binding you need to tell view that it changed
You need to make your poco class within the ObservableCollection implement INotifyPropertyChanged.
Example:
<viewModels:LocationsViewModel x:Key="viewModel" />
.
.
.
<ListView
DataContext="{StaticResource viewModel}"
ItemsSource="{Binding Locations}"
IsItemClickEnabled="True"
ItemClick="GroupSection_ItemClick"
ContinuumNavigationTransitionInfo.ExitElementContainer="True">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Name}" Margin="0,0,10,0" Style="{ThemeResource ListViewItemTextBlockStyle}" />
<TextBlock Text="{Binding Latitude, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Style="{ThemeResource ListViewItemTextBlockStyle}" Margin="0,0,5,0"/>
<TextBlock Text="{Binding Longitude, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Style="{ThemeResource ListViewItemTextBlockStyle}" Margin="5,0,0,0" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
public class LocationViewModel : BaseViewModel
{
ObservableCollection<Location> _locations = new ObservableCollection<Location>();
public ObservableCollection<Location> Locations
{
get
{
return _locations;
}
set
{
if (_locations != value)
{
_locations = value;
OnNotifyPropertyChanged();
}
}
}
}
public class Location : BaseViewModel
{
int _locationId = 0;
public int LocationId
{
get
{
return _locationId;
}
set
{
if (_locationId != value)
{
_locationId = value;
OnNotifyPropertyChanged();
}
}
}
string _name = null;
public string Name
{
get
{
return _name;
}
set
{
if (_name != value)
{
_name = value;
OnNotifyPropertyChanged();
}
}
}
float _latitude = 0;
public float Latitude
{
get
{
return _latitude;
}
set
{
if (_latitude != value)
{
_latitude = value;
OnNotifyPropertyChanged();
}
}
}
float _longitude = 0;
public float Longitude
{
get
{
return _longitude;
}
set
{
if (_longitude != value)
{
_longitude = value;
OnNotifyPropertyChanged();
}
}
}
}
public class BaseViewModel : INotifyPropertyChanged
{
#region Events
public event PropertyChangedEventHandler PropertyChanged;
#endregion
protected void OnNotifyPropertyChanged([CallerMemberName] string memberName = "")
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(memberName));
}
}
}
Your Subcategories property should be read-only.