new to WPF and programming here I am trying to update an item in a ListView when a button is pushed if the item already exists in that ListView, for example a user inputs CAR and CAR is already in the ListView the CAR count should go from 1 to 2.
This is my InventoryItem class:
public class InventoryItem
{
public string Name { get; set; }
public int Count { get; set; }
}
Here is my ViewModel
public class ViewModel : ViewModelBase
{
private InventoryItem _item;
private int _count;
private ObservableCollection<InventoryItem> _inventoryItems;
private ICommand _addItem;
public InventoryItem Item
{
get
{
return _item;
}
set
{
_item = value;
NotifyPropertyChanged("Item");
}
}
public int Count
{
get { return _count; }
set { _count = value; NotifyPropertyChanged("Count"); }
}
public ObservableCollection<InventoryItem> InventoryItems
{
get
{
return _inventoryItems;
}
set
{
_inventoryItems = value;
NotifyPropertyChanged("Items");
}
}
public ICommand AddItem
{
get
{
if (_addItem == null)
{
_addItem = new RelayCommand(ParamArrayAttribute => this.Submit(), null);
}
return _addItem;
}
}
public ViewModel()
{
Item = new InventoryItem();
InventoryItems = new ObservableCollection<InventoryItem>();
InventoryItems.CollectionChanged += new NotifyCollectionChangedEventHandler(InventoryItems_CollectionChanged);
}
void InventoryItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
NotifyPropertyChanged("Items");
NotifyPropertyChanged("Count");
}
private void Submit()
{
if (InventoryItems.Any(p => p.Name == Item.Name))
{
InventoryItems.First(x => x.Name == Item.Name).ItemCount++;
}
else
{
InventoryItems.Add(Item);
}
}
}
Here is my View
<ListView x:Name="listBox" ItemsSource="{Binding InventoryItems}" Grid.Row="0" HorizontalAlignment="Stretch" Height="Auto" Margin="10,10,10,60" VerticalAlignment="Stretch">
<ListView.Resources>
<Style TargetType="GridViewColumnHeader">
<Setter Property="Visibility" Value="Collapsed"/>
</Style>
</ListView.Resources>
<ListView.View>
<GridView>
<GridViewColumn DisplayMemberBinding="{Binding Name}" Width="Auto"/>
<GridViewColumn DisplayMemberBinding="{Binding ItemCount}" Width="Auto"/>
</GridView>
</ListView.View>
</ListView>
Whenever an item that exists in the list is typed in it appears that the InventoryItems ObservableCollection is being updated however InventoryItems_CollectionChanged event is not being fired so the ListView is not being updated. Isn't the collection changing so that event should be fired to update the ListView or am I not understanding the Binding and the event?
You need to notify about property changes in the InventoryItem class to update the changes of ItemCount in the ListView.
Quick solution:
public class InventoryItem : ViewModelBase
{
public string Name
{
get { return _name; }
set
{
if (_name != value)
{
_name = value;
NotifyPropertyChanged(nameof(Name));
}
}
}
private string _name;
public int ItemCount
{
get { return _itemCount; }
set { _itemCount = value; NotifyPropertyChanged(nameof(ItemCount));
}
}
private int _itemCount;
}
}
The ObservableCollection class already contains handling of INotifyCollectionChanged.
You only need this line for the ObservableCollection. You can remove everything else that has to do with "InventoryItems" and the collection in your ViewModel.
public ObservableCollection<InventoryItem> InventoryItems { get; } = new ObservableCollection<InventoryItem>();
Also: When you add an item to the collection you need to create a new item. Otherwise you are adding the same object, that will not work.
This is my reduced ViewModel to how I think you want it to work:
public class ViewModel : ViewModelBase
{
private ICommand _addItem;
public string InputName
{
get { return _inputName; }
set
{
if (_inputName != value)
{
_inputName = value;
NotifyPropertyChanged(nameof(InputName));
}
}
}
private string _inputName;
public ObservableCollection<InventoryItem> InventoryItems { get; } = new ObservableCollection<InventoryItem>();
public ICommand AddItem
{
get
{
if (_addItem == null)
{
_addItem = new RelayCommand(ParamArrayAttribute => this.Submit(), null);
}
return _addItem;
}
}
private void Submit()
{
if (InventoryItems.Any(p => p.Name == InputName))
{
InventoryItems.First(x => x.Name == InputName).ItemCount++;
}
else
{
InventoryItems.Add(new InventoryItem() { Name = InputName, ItemCount = 1 });
}
}
}
To complete the picture, I have added following XAML for test:
<TextBox Text="{Binding InputName}" MinWidth="100" Margin="5"/>
<Button Content="Add" Command="{Binding AddItem}" Margin="5"/>
Related
Avalonia.UI ComboBox doesn't have SelectedValuePath & DisplayMemberPath and I'm not skilled enough to implement them.
I have experimented with a TemplatedControl as a work-around because I'm using a TemplatedControl anyway and I don't want to have extra Properties on the ViewModel to handle it.
What I'm trying to archive is to show the items in the ComboBox by DisplayMember but loading/saving by Id. In this test case by Project.ManagerId. It's working but it would be nice not to have to hard-code the Type in that TemplatedControl code behind, like I do right now with "LookupItem". It should be possible to get around that by setting x:DataType="viewModels:LookupItem" or something.
Any ideas?
I have removed most not relevant code.
<Styles xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:controls="using:ChangeTrackingHeaderControls.Controls">
<Design.PreviewWith>
<controls:ChangeTrackingHeaderComboBox />
</Design.PreviewWith>
<Style Selector="controls|ChangeTrackingHeaderComboBox">
<!-- Set Defaults -->
<Setter Property="Template">
<ControlTemplate>
<ComboBox Items="{TemplateBinding Items, Mode=OneWay}"
SelectedItem="{TemplateBinding SelectedItem, Mode=TwoWay}"
SelectedIndex="{TemplateBinding SelectedIndex, Mode=TwoWay}"
ItemTemplate="{TemplateBinding ItemTemplate}"
HorizontalAlignment="Stretch" />
</ControlTemplate>
</Setter>
</Style>
</Styles>
public class ChangeTrackingHeaderComboBox : TemplatedControl
{
private object? _selectedItem;
private int? _selectedValue;
public static readonly DirectProperty<ChangeTrackingHeaderComboBox, object?> SelectedItemProperty =
AvaloniaProperty.RegisterDirect<ChangeTrackingHeaderComboBox, object?>(nameof(SelectedItem),
o => o.SelectedItem,
(o, v) => o.SelectedItem = v,
defaultBindingMode: BindingMode.TwoWay,
enableDataValidation: true);
public static readonly DirectProperty<ChangeTrackingHeaderComboBox, int?> SelectedValueProperty =
AvaloniaProperty.RegisterDirect<ChangeTrackingHeaderComboBox, int?>(nameof(SelectedValue),
o => o.SelectedValue,
(o, v) => o.SelectedValue = v,
defaultBindingMode: BindingMode.TwoWay,
enableDataValidation: true);
public static readonly StyledProperty<IEnumerable> ItemsProperty = AvaloniaProperty
.Register<ChangeTrackingHeaderComboBox, IEnumerable>(nameof(Items));
public static readonly StyledProperty<int> SelectedIndexProperty = AvaloniaProperty
.Register<ChangeTrackingHeaderComboBox, int>(nameof(SelectedIndex));
public static readonly StyledProperty<IDataTemplate> ItemTemplateProperty = AvaloniaProperty
.Register<ChangeTrackingHeaderComboBox, IDataTemplate>(nameof(ItemTemplate));
public object? SelectedItem
{
get => _selectedItem;
set
{
SetAndRaise(SelectedItemProperty, ref _selectedItem, value);
OnSelectedItemChanged();
}
}
public int? SelectedValue
{
get => _selectedValue;
set
{
SetAndRaise(SelectedValueProperty, ref _selectedValue, value);
OnSelectedValueChanged();
}
}
public IEnumerable Items
{
get => GetValue(ItemsProperty);
set => SetValue(ItemsProperty, value);
}
public int SelectedIndex
{
get => GetValue(SelectedIndexProperty);
set => SetValue(SelectedIndexProperty, value);
}
public IDataTemplate ItemTemplate
{
get => GetValue(ItemTemplateProperty);
set => SetValue(ItemTemplateProperty, value);
}
protected override void UpdateDataValidation(AvaloniaProperty property, BindingValueType state, Exception? error)
{
base.UpdateDataValidation(property, state, error);
if (property == SelectedItemProperty)
{
DataValidationErrors.SetError(this, error);
}
if (property == SelectedValueProperty)
{
DataValidationErrors.SetError(this, error);
}
}
private void OnSelectedItemChanged()
{
// LookupItem should not be hard coded
if (SelectedItem is LookupItem selectedItem)
{
if (SelectedValue == selectedItem.Id) return;
if (Items is IEnumerable<LookupItem> items)
{
var selectedItemDisplayMember = selectedItem.DisplayMember;
SelectedValue = items.SingleOrDefault(x => x.DisplayMember == selectedItemDisplayMember).Id;
}
}
}
private void OnSelectedValueChanged()
{
// LookupItem should not be hard coded
if (Items is IEnumerable<LookupItem> items)
{
if (SelectedItem == null)
{
SelectedItem = items.SingleOrDefault(x => x.Id == SelectedValue);
return;
}
if (SelectedItem is LookupItem selectedItem)
{
if (selectedItem.Id == SelectedValue) return;
SelectedItem = items.SingleOrDefault(x => x.Id == SelectedValue);
}
}
}
}
// App.axaml
<Application xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:controls="clr-namespace:ChangeTrackingHeaderControls.Controls"
xmlns:viewModels="clr-namespace:ChangeTrackingHeaderControls.ViewModels"
x:Class="ChangeTrackingHeaderControls.App">
<Application.Resources>
<DataTemplate x:Key="LookupItemItemTemplate" x:DataType="viewModels:LookupItem">
<ComboBoxItem Content="{CompiledBinding DisplayMember}"
HorizontalContentAlignment="Left"
VerticalContentAlignment="Center" />
</DataTemplate>
</Application.Resources>
<Application.Styles>
<FluentTheme Mode="Light" />
<StyleInclude Source="/Controls/ChangeTrackingHeaderComboBox.axaml" />
</Application.Styles>
</Application>`
// MainWindow
<controls:ChangeTrackingHeaderComboBox Items="{CompiledBinding Managers}"
SelectedValue="{CompiledBinding Project.ManagerId}"
ItemTemplate="{StaticResource LookupItemItemTemplate}" />
// ViewModel
public sealed class MainViewModel : ViewModelBase
{
private Project _project;
public MainViewModel()
{
Managers = new ObservableCollection<LookupItem>();
// Simulating loading Managers from database
for (var i = 1; i < 12; i++)
{
Managers.Add(new LookupItem
{
Id = i,
DisplayMember = $"Manager {i}"
});
}
// One single Project loaded from database
Project = new Project
{
Id = 1,
Name = "Project 1",
ManagerId = Managers.LastOrDefault()?.Id
};
}
public ObservableCollection<LookupItem> Managers { get; }
public Project Project
{
get => _project;
private set
{
if (value == _project) return;
_project = value;
OnPropertyChanged();
}
}
}
// Models
public sealed class Project
{
public int Id { get; set; }
public string Name { get; set; }
public int? ManagerId { get; set; }
}
public sealed class LookupItem
{
public int Id { get; init; }
public string DisplayMember { get; init; }
}```
I have tried to use x:DataType="viewModels:LookupItem" and also implemented StyledProperty<Type> but no succcess.
On the ViewModel instances bound to the ComboBox's Items property, override ToString() and return the value you want displayed in the open drop down.
I have a simple ListBox and a TextBox as under.I want to display the selectedvalue property of Listbox in the textbox,but my ViewModel's selected object is always null.
What am i missing here?
My XAML
<StackPanel>
<Canvas>
<TextBox x:Name="TxtMail" Width="244" FontSize="14" Canvas.Left="36" Canvas.Top="34" Height="20" Text="{Binding CurrentRec.Name,Mode=OneWay}" />
<ListBox x:Name="AllMatching" Width="{Binding ElementName=TxtMail,Path=Width}" Height="100" Canvas.Top="54" Canvas.Left="36" DisplayMemberPath="Name" SelectedItem="{Binding CurrentRec,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" SelectedValue="Name" SelectedValuePath="Name" ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.HorizontalScrollBarVisibility="Auto" />
<Button Content="Test" x:Name="cmdtest" Click="cmdtest_Click"/>
</Canvas>
My ViewModel:
public class VM_Data : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public int p_ID;
public double p_SP, p_CP;
public string p_Name;
public List<DM_Data> AllData;
public DM_Data CurrentRec;
public VM_Data()
{
LoadData();
}
public int ID
{
get { return p_ID; }
set
{
if (p_ID != value)
{
RaisePropertyChangedEvent("ID");
p_ID = value;
}
}
}
public double SP
{
get { return p_SP; }
set
{
if (p_SP != value)
{
RaisePropertyChangedEvent("SP");
p_SP = value;
}
}
}
public double CP
{
get { return p_CP; }
set
{
if (p_CP != value)
{
RaisePropertyChangedEvent("CP");
p_CP = value;
}
}
}
public string Name
{
get { return p_Name; }
set
{
if (p_Name != value)
{
RaisePropertyChangedEvent("Name");
p_Name = value;
}
}
}
private void LoadData()
{
AllData = new List<DM_Data>();
string[] strNames = "Jatinder;Shashvat;shashikala;shamsher;shahid;justin;jatin;jolly;ajay;ahan;vijay;suresh;namita;nisha;negar;zenith;zan;zen;zutshi;harish;hercules;harman;ramesh;shashank;mandeep;aman;amandeep;amarjit;asim;akshay;amol;ritesh;ritivik;riz;samana;samaira;bhagwandass;bhagwan;bhawna;bhavna".Split(';');
for(int i=0;i<=strNames.GetUpperBound(0);i++)
{
DM_Data NewRec = new DM_Data();
NewRec.CP = new Random().Next(200, 400);
NewRec.SP = new Random().Next(1, 10);
NewRec.ID = i + 1;
NewRec.Name = strNames[i];
AllData.Add(NewRec);
}
AllData = AllData.OrderBy(item => item.Name).ToList();
}
private void RaisePropertyChangedEvent(string Property)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(Property));
}
}
}
My DataModel
public class DM_Data
{
public int p_ID;
public double p_SP, p_CP;
public string p_Name;
public int ID
{
get { return p_ID; }
set { p_ID = value; }
}
public double SP
{
get { return p_SP; }
set { p_SP = value; }
}
public double CP
{
get { return p_CP; }
set { p_CP = value; }
}
public string Name
{
get { return p_Name; }
set { p_Name = value; }
}
MainWindow.Xaml.cs
public partial class MainWindow : Window
{
VM_Data ViewModel;
public MainWindow()
{
InitializeComponent();
ViewModel = new VM_Data();
this.DataContext = ViewModel;
AllMatching.ItemsSource = ViewModel.AllData;
}
private void cmdtest_Click(object sender, RoutedEventArgs e)
{
DM_Data crec = ViewModel.CurrentRec;
}
}
CurrentRec must be a property that raises the PropertyChanged event:
private DM_Data _currentRec;
public DM_Data CurrentRec
{
get { return _currentRec; }
set { _currentRec = value; RaisePropertyChangedEvent("CurrentRec"); }
}
In the code you have posted, it is a field and you cannot bind to fields:
public DM_Data CurrentRec;
You can't bind to fields! CurrentRec must be a property. At now it is a field.
Why do you set ItemsSource in code-behind? Set it in XAML.
You should call RaisePropertyChangedEvent after you've changed backing field, not before.
It is not right pattern for events raising: if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(Property)); } You need to save event delegate to variable first or use ?.Invoke.
Don't create new instances of Random on every iteration of loop because you will get equal values. Create the only one outside of the loop and use it.
What you are doing is kind of MVVM, but not really.
Here is a quick fix anyway:
Please take a look at the Bindings.
<StackPanel>
<Canvas>
<TextBox x:Name="TxtMail" Width="244" FontSize="14" Canvas.Left="36" Canvas.Top="34" Height="20" Text="{Binding ElementName=AllMatching, Path=SelectedItem.Name}" />
<ListBox x:Name="AllMatching"
Width="{Binding ElementName=TxtMail,Path=Width}"
Height="100"
Canvas.Top="54"
Canvas.Left="36"
DisplayMemberPath="Name"
SelectedItem="{Binding CurrentRec,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollBarVisibility="Auto" />
<Button Content="Test" x:Name="cmdtest" Click="cmdtest_Click"/>
</Canvas>
</StackPanel>
I think you get the idea at: Text="{Binding ElementName=AllMatching, Path=SelectedItem.Name}".
Aditional Information
First:
You fire to early dude. Please first assign the value and then say its changed.
if (p_Name != value)
{
RaisePropertyChangedEvent("Name");
p_Name = value;
}
Second:
Use a ObservableCollection<DM_Data> to let your ListBox know about changes.
Third:
Use the posibility of Binding
Remove AllMatching.ItemsSource = ViewModel.AllData; and go like
<ListBox x:Name="AllMatching"
ItemsSource="{Binding Path=AllData}"
...
/>
And after all of this - please man check out some tutorials. And also refactor your code from VM_Data to DataViewModel thank you sir.
I am trying to write a simple application where I display a listview using databinding containing multiple objects that lists their properties and a check box. I let the user check all of the boxes they want removed then press a button that removes the selected elements.
public partial class MainWindow : Window
{
ObservableCollection<User> Users = new ObservableCollection<User>();
public MainWindow()
{
System.Console.WriteLine("main window");
Users.Add(new User() { Name = "John Doe", Age = 42, Height = "6ft", Checked = false});
Users.Add(new User() { Name = "Jane Doe", Age = 39, Height = "6ft", Checked = false });
Users.Add(new User() { Name = "Sammy Doe", Age = 7, Height = "5ft", Checked = false });
drawFolderView();
}
private void drawFolderView()
{
InitializeComponent();
lvUsers.ItemsSource = Users;
}
private void button_Click(object sender, RoutedEventArgs e)
{
if (Users.Count > 0)
{
List<User> itemsToRemove = new List<User>();
foreach (User person in Users)
{
if (person.Checked)
{
itemsToRemove.Add(person);
}
}
foreach (User person in itemsToRemove)
{
Users.Remove(person);
}
}
else
{
System.Console.WriteLine("nothing in list");
}
drawFolderView();
}
private void CheckBox_Checked(object sender, RoutedEventArgs e)
{
}
private void CheckBox_Unchecked(object sender, RoutedEventArgs e)
{
}
}
public class User
{
public string Name { get; set; }
public int Age { get; set; }
public string Height { get; set; }
public bool Checked { get; set; }
public bool Equals(User other) {
if (Name.Equals(other.Name))
{
return true;
}
else
{
return false;
}
}
}
From reading the other questions I made the CheckBox_Checked and Unchecked methods, but I have no idea how to implement them.
Window x:Class="WpfApplication6.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApplication6"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Grid>
<ListView Margin="10,10,10,98" Name="lvUsers">
<ListView.View>
<GridView>
<GridViewColumn Header="Name" Width="120" DisplayMemberBinding="{Binding Name}" />
<GridViewColumn Header="Age" Width="50" DisplayMemberBinding="{Binding Age}" />
<GridViewColumn Header="Height" Width="150" DisplayMemberBinding="{Binding Height}" />
<GridViewColumn Width="60">
<GridViewColumn.CellTemplate>
<DataTemplate>
<CheckBox Margin="-4,0,-4,0" IsChecked="{Binding MyBoolProperty}" Checked="CheckBox_Checked" Unchecked="CheckBox_Unchecked" DataContext="{Binding Checked}" />
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
</GridView>
</ListView.View>
</ListView>
<Button x:Name="button" Content="Delete" HorizontalAlignment="Left" Margin="353,243,0,0" VerticalAlignment="Top" Width="75" Click="button_Click" />
</Grid>
Is this a reasonable approach? Many of the concepts surrounding databinding in WPF still confuse me.
The Checkbox should be changed to this:
<CheckBox Margin="-4,0,-4,0" IsChecked="{Binding Checked}" />
The DataContext for the Checkbox is the User (like it is for the other columns). The IsChecked property of the Checkbox is bound to the Checked property on the User.
There is no need to call drawFolderView in the button_click method. The lvUsers.ItemsSource is already set to Users. Since Users is an ObservableCollection, it will raise events to tell WPF that items were removed/added and your listview will update itself automatically.
To work best with WPF, your User class should implement INotifyPropertyChanged. When the properties of User objects change, your bindings will get updated automatically. Right now, only the listview can change the User objects so you won't get any real benefit from INPC. But, if you added a button that looped through the Users and set User.Checked = true then you would need the INPC interface to tell WPF that the Checked property on the User objects changed so it could update the GUI.
Also, InitializeComponent() should be moved back to the top of the constructor. You only want that called when the window is being created.
Here is an updated version of your code with a few changes:
public partial class MainWindow : Window
{
ObservableCollection<User> Users = new ObservableCollection<User>();
public MainWindow()
{
InitializeComponent();
System.Console.WriteLine("main window");
Users.Add(new User() { Name = "John Doe", Age = 42, Height = "6ft", Checked = false });
Users.Add(new User() { Name = "Jane Doe", Age = 39, Height = "6ft", Checked = false });
Users.Add(new User() { Name = "Sammy Doe", Age = 7, Height = "5ft", Checked = false });
lvUsers.ItemsSource = Users;
}
private void button_Click(object sender, RoutedEventArgs e)
{
if (Users.Count > 0)
{
List<User> itemsToRemove = new List<User>();
foreach (User person in Users)
{
if (person.Checked)
{
itemsToRemove.Add(person);
}
}
foreach (User person in itemsToRemove)
{
Users.Remove(person);
}
}
else
{
System.Console.WriteLine("nothing in list");
}
}
}
public class User : System.ComponentModel.INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OPC(string propertyName) // OPC = OnPropertyChanged; a helper that raises the PropertyChanged event
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private string _name;
public string Name
{
get { return _name; }
set
{
if (_name != value)
{
_name = value;
OPC("Name");
}
}
}
private int _age;
public int Age { get { return _age; } set { if (_age != value) { _age = value; OPC("Age"); } } }
private string _height;
public string Height { get { return _height; } set { if (_height != value) { _height = value; OPC("Height"); } } }
private bool _checked;
public bool Checked { get { return _checked; } set { if (_checked != value) { _checked = value; OPC("Checked"); } } }
public bool Equals(User other)
{
if (Name.Equals(other.Name))
{
return true;
}
else
{
return false;
}
}
}
My previous post about detecting property changes in the VM wasn't in depth enough, so I'm posting this
I have a grid of Jobs. Each job can have one or more employees.
The DataGrid's RowDetailsTemplate contains another grid to show the employees. So to parent grid is bound to a list of Jobs. The inner grid is bound to a list of Employees that is on the Job model.
The Job Model:
public class Job : _Base
{
private string _JobName = string.Empty;
public string JobName
{
get { return _JobName; }
set
{
if (_JobName != value)
{
_JobName = value;
RaisePropertyChanged("JobName");
}
}
}
private string _JobNumber = string.Empty;
public string JobNumber
{
get { return _JobNumber; }
set
{
if (_JobNumber != value)
{
_JobNumber = value;
RaisePropertyChanged("JobNumber");
}
}
}
private ObservableCollection<Employee> _Employees;
public ObservableCollection<Employee> Employees
{
get { return _Employees; }
set
{
if (_Employees != value)
{
if (_Employees != value)
{
_Employees = value;
RaisePropertyChanged("Employees");
}
}
}
}
private Employee _SelectedEmployee;
public Employee SelectedEmployee
{
get { return _SelectedEmployee; }
set
{
if (_SelectedEmployee != value)
{
if (_SelectedEmployee != value)
{
_SelectedEmployee = value;
RaisePropertyChanged("SelectedEmployee");
}
}
}
}
public Job()
{
Employees = new ObservableCollection<Employee>();
}
}
The Employee model
public class Employee : _Base
{
private string _EmployeeName = string.Empty;
public string EmployeeName
{
get { return _EmployeeName; }
set
{
if (_EmployeeName != value)
{
_EmployeeName = value;
RaisePropertyChanged("EmployeeName");
}
}
}
private bool _IsChecked = false;
public bool IsChecked
{
get { return _IsChecked; }
set
{
if (_IsChecked != value)
{
_IsChecked = value;
RaisePropertyChanged("IsChecked");
}
}
}
}
The XAML
<DataGrid ItemsSource="{Binding Jobs}"
SelectedItem="{Binding SelectedJob}"
AutoGenerateColumns="False">
<DataGrid.Columns>
<DataGridTextColumn Header="Job Name" Binding="{Binding JobName}" />
<DataGridTextColumn Header="Job Number" Binding="{Binding JobNumber}" />
</DataGrid.Columns>
<DataGrid.RowDetailsTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<DataGrid ItemsSource="{Binding Employees}"
SelectedItem="{Binding SelectedEmployee}"
AutoGenerateColumns="False">
<DataGrid.Columns>
<DataGridCheckBoxColumn Binding="{Binding IsChecked}"/>
<DataGridTextColumn Binding="{Binding EmployeeName}"/>
</DataGrid.Columns>
</DataGrid>
<Button Margin="5"
Height="23"
Width="75"
HorizontalAlignment="Left"
Content="Remove"/>
</StackPanel>
</DataTemplate>
</DataGrid.RowDetailsTemplate>
</DataGrid>
The MainWindowViewModel
public class MainWindowViewModel : _Base
{
private ObservableCollection<Job> _Jobs;
public ObservableCollection<Job> Jobs
{
get { return _Jobs; }
set
{
if (_Jobs != value)
{
if (_Jobs != value)
{
_Jobs = value;
RaisePropertyChanged("Jobs");
}
}
}
}
private Job _SelectedJob;
public Job SelectedJob
{
get { return _SelectedJob; }
set
{
if (_SelectedJob != value)
{
if (_SelectedJob != value)
{
_SelectedJob = value;
RaisePropertyChanged("SelectedJob");
}
}
}
}
public MainWindowViewModel()
{
this.PropertyChanged += new PropertyChangedEventHandler(MainWindowViewModel_PropertyChanged);
}
void MainWindowViewModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (e.PropertyName.Trim().ToLower() == "ischecked")
{
int x = 1;
}
}
}
I have a couple of questions:
1) The SelectedEmployee property on the Job model does not fire when I click an employee in the inner grid.
2) The MainWindowViewModel_PropertyChanged does not fire when an employee is selected.
3) Notice the button below the inner grid. How do I bind its command to MainWindowVM?
As you have DataGridinside DataGrid's row, so the above DataGrid is somehow eating up the selectionchange for the inner DataGrid. To solve this, you will need to forcefully update the binding source for the child DataGrid. For doing so capture the SelectionChanged event for the inner DataGrid and in the handler do the following.
private void DataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
DataGrid grid = e.OriginalSource as DataGrid;
var expression = grid.GetBindingExpression(DataGrid.SelectedItemProperty);
expression.UpdateSource();
}
MainwindowVM does not have any ischecked property thats why its propertychanged for that property is not firing.
To solve this you need to do couple of things. The problem is DataGrid cell and rows does not inherit the DataContext as they don't come under its visual tree. So to solve this you will have to use the BindingProxy to take the windows DataContext to your button in rowdetails of DataGrid
Define Binding Proxy class as below:
public class MyBindingProxy : Freezable
{
public static readonly DependencyProperty BindingDataProperty =
DependencyProperty.Register("BindingData", typeof(object),
typeof(MyBindingProxy), new UIPropertyMetadata(null));
protected override Freezable CreateInstanceCore()
{
return new MyBindingProxy();
}
public object BindingData
{
get { return (object)GetValue(BindingDataProperty); }
set { SetValue(BindingDataProperty, value); }
}
}
Now in the resources of your window (where DataGrid is) create the instance of proxy and set the BindingData to the DataContext of the Window i.e MainWindowViewModel as:
<Window.Resources>
<local:MyBindingProxy x:Key="myproxy" BindingData="{Binding}" />
</Window.Resources>
Now just set command as below on the button:
<Button Margin="5"
Height="23"
Width="75"
HorizontalAlignment="Left"
Content="Remove"
Command="{Binding BindingData.MyCommand, Source={StaticResource myproxy}}"/>
I have an wpf mvvm application. I try to write checkbox list control.
I can bind the checkbox list elements.
Added to this issue, I want to get sum of the selected checkbox list elements values.
I added DependencyProperty and bind it to view model property.
But, they dont fire each other.
CheckBoxList User Control Xaml
<ListBox x:Name="ItemsControl" ItemsSource="{Binding}">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Content="{Binding Text}" IsChecked="{Binding IsSelected, Mode=TwoWay}"
Checked="CheckBox_Checked" Unchecked="CheckBox_Checked" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
CheckBoxList Code Behind
public partial class CheckBoxList : UserControl
{
public CheckBoxList()
{
InitializeComponent();
}
public static readonly DependencyProperty SelectedCheckBoxItemsValueProperty =
DependencyProperty.Register("SelectedCheckBoxItemsValue", typeof(int), typeof(CheckBoxList),
new FrameworkPropertyMetadata(
0,
new FrameworkPropertyMetadata(0, OnSelectedItemsChanged));
public int SelectedCheckBoxItemsValue
{
get { return (int)GetValue(SelectedCheckBoxItemsValueProperty); }
set { SetValue(SelectedCheckBoxItemsValueProperty, value); }
}
private static int GetSelectedCheckBoxItemsValue(DependencyObject obj)
{
return (int)obj.GetValue(SelectedCheckBoxItemsValueProperty);
}
private static void OnSelectedItemsChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
CheckBoxList checkboxList = obj as CheckBoxList;
ObservableCollection<ISelectableItem> items = checkboxList.DataContext as ObservableCollection<ISelectableItem>;
foreach (var item in items)
{
item.IsSelected = (GetSelectedCheckBoxItemsValue(obj) & item.Value) != 0;
}
}
private void CheckBox_Checked(object sender, RoutedEventArgs e)
{
CheckBoxList checkboxList = sender as CheckBoxList;
ObservableCollection<ISelectableItem> coll = ItemsControl.DataContext as ObservableCollection<ISelectableItem>;
if (coll == null) return;
int count = 0;
foreach (var item in coll)
{
if (item.IsSelected)
{
count += item.Value;
}
}
SelectedCheckBoxItemsValue = count;
}
}
SelectableItem Class
public interface ISelectableItem : INotifyPropertyChanged
{
bool IsSelected { get; set; }
string Text { get; set; }
int Value { get; set; }
string GroupName { get; set; }
}
public class SelectableItem : ISelectableItem
{ ....
ViewModel Property
public int SelectedCheckBoxEnumItemsValue
{
get
{
return _selectedCheckBoxEnumItemsValue;
}
set
{
_selectedCheckBoxEnumItemsValue = value;
NotifyOfPropertyChange("SelectedCheckBoxEnumItemsValue");
}
}
At Binder Class
string selectedItemPropertyName = "Selected" + viewModelProperty.Name + "Value";
var property = viewModelProperties.FirstOrDefault(p => p.Name.Contains(selectedItemPropertyName));
if (property != null)
{
var selectedItemOrValueBinding = new Binding(property.Name)
{
Mode = property.CanWrite ? BindingMode.TwoWay : BindingMode.OneWay,
ValidatesOnDataErrors = Attribute.GetCustomAttributes(property, typeof(ValidationAttribute), true).Any()
};
BindingOperations.SetBinding(control, CheckBoxList.SelectedCheckBoxItemsValueProperty, selectedItemOrValueBinding);
}
Below code solves your problem..
Please Note the segrgation of view models.
<StackPanel>
<TextBlock Text="{Binding Count}"></TextBlock>
<ListBox x:Name="ItemsControl" ItemsSource="{Binding CheckList}">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Name="item" Content="{Binding Text}" IsChecked="{Binding IsSelected, Mode=TwoWay}" Command="{Binding CheckboxCheckedCommand}" CommandParameter="{Binding IsChecked, ElementName=item}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MasterViewModel();
}
}
public class MasterViewModel : INotifyPropertyChanged
{
private List<CheckBoxItem> checkList;
private int count;
public int Count
{
get
{
return count;
}
set
{
count = value;
OnPropertyChanged("Count");
}
}
public List<CheckBoxItem> CheckList
{
get
{
return checkList;
}
set
{
checkList = value;
OnPropertyChanged("CheckList");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public MasterViewModel()
{
checkList = new List<CheckBoxItem>();
for (int i = 0; i < 5; i++)
{
CheckBoxItem item = new CheckBoxItem();
item.Text = i.ToString();
item.IsSelected = false;
item.CheckboxCheckedCommand = new RelayCommand(new Action<object>(ExecuteCheckCommand));
checkList.Add(item);
}
}
private void ExecuteCheckCommand(object parameter)
{
if (parameter.GetType() == typeof(bool))
{
bool value = bool.Parse(parameter.ToString());
int val = count;
if (value)
{
val++;
}
else
{
val--;
}
Count = val;
}
}
private void OnPropertyChanged(string p)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(p));
}
}
}
public class CheckBoxItem : INotifyPropertyChanged
{
private bool isSelected;
private string text;
public string Text
{
get
{
return text;
}
set
{
text = value;
OnPropertyChanged("Text");
}
}
public bool IsSelected
{
get
{
return isSelected;
}
set
{
isSelected = value;
OnPropertyChanged("IsSelected");
}
}
public ICommand CheckboxCheckedCommand
{
get;
set;
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string p)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(p));
}
}
}
public class RelayCommand : ICommand
{
private Action<object> executeCommand;
public RelayCommand(Action<object> executeCommand)
{
this.executeCommand = executeCommand;
}
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
executeCommand(parameter);
}
}