[Solved]: I have provided a working example in the answer below.
Related thread on [SO][1]
I have read many threads here, how to bind an enum to a combobox.
I got it to work oneway with another approach using a MarkupExtension!
But then I don't have twoway binding available.
I want to bind it to an Enum property of my ViewModel.
When I try this approach:
<Window.Resources>
<ObjectDataProvider MethodName="GetValues"
ObjectType="{x:Type sys:Enum}"
x:Key="DetailScopeDataProvider">
<ObjectDataProvider.MethodParameters>
<x:Type TypeName="local:DetailScope" />
</ObjectDataProvider.MethodParameters>
</ObjectDataProvider>
One further problem here is, that VS intellisense does not offer me this:
sys:Enum
I also don't know to setup the ItemSource and SelectedValue property of the combobox.
Ok, got it working.
The ObjectDataProvider has an ObjectType Property. As I want to use an Enum Property of my viewmodel as a datasource for the combobox.
The Object Type in this case is:
System.Enum
which resides in the System namespace in the mscorlib assembly.
We therefore have to add import the namespace in our XAML:
xmlns:sys="clr-namespace:System;assembly=mscorlib"
Here I will post the whole code for reference:
Test.xaml(window):
<Window x:Class="WpfTrash.Test"
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:WpfTrash"
-->> xmlns:sys="clr-namespace:System;assembly=mscorlib" <<--
mc:Ignorable="d"
Title="Test" Height="300" Width="300">
<Window.Resources>
<local:MyEnumToStringConverter x:Key="MyEnumConverter" />
<ObjectDataProvider x:Key="odp" MethodName="GetNames" ObjectType="{x:Type sys:Enum}">
<ObjectDataProvider.MethodParameters>
<x:Type TypeName="local:TheEnum"/>
</ObjectDataProvider.MethodParameters>
</ObjectDataProvider>
</Window.Resources>
<StackPanel>
<TextBox x:Name="txtTheInt" Text="{Binding Path=TheInt}"/>
<TextBox x:Name="txtTheString" Text="{Binding Path=TheString}"/>
<!--<ComboBox x:Name="cboTheEnum" DataContext="{StaticResource SortedEnumView}" ItemsSource="{Binding}"/>-->
<ComboBox x:Name="cboTheEnum" ItemsSource="{Binding Source={StaticResource odp}}" SelectedValue="{Binding Path=TheEnum, Converter={StaticResource MyEnumConverter}}"/>
<Button x:Name="button" Content="Button" Click="button_Click"/>
</StackPanel>
</Window>
Test.xaml.cs
namespace WpfTrash
{
/// <summary>
/// Interaction logic for Test.xaml
/// </summary>
public partial class Test : Window
{
MyClass vm = new MyClass();
public Test()
{
InitializeComponent();
this.DataContext = vm;
}
private void button_Click(object sender, RoutedEventArgs e)
{
var selecteditem = (TheEnum)Enum.Parse(typeof(TheEnum), cboTheEnum.SelectedItem.ToString(), true);
}
}
}
The viewmodel:
public class MyClass : INotifyPropertyChanged
{
public int TheInt { get; set; }
public string TheString { get; set; }
TheEnum theEnum;
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public TheEnum TheEnum
{
get
{
return theEnum;
}
set
{
theEnum = value;
NotifyPropertyChanged("TheEnum");
}
}
}
The Enum definition: (is not part of a class definition)
public enum TheEnum
{
A, B, C, D
}
The Converter:
public class MyEnumToStringConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return value.ToString();
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return (TheEnum)Enum.Parse(typeof(TheEnum), value.ToString(), true);
}
}
Related
I am trying to bind an enum to a combobox in a WPF-Usercontrol. I already got the different enum-values in, but the binding to my viewmodel doesn't work.
My Usercontroll:
UserControl
x:Class="XpTimeWriter.UserControls.FooterBar"
x:Name="me"
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:enums="clr-namespace:XpTimeWriter.Enums"
xmlns:local="clr-namespace:XpTimeWriter.UserControls"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="80"
d:DesignWidth="800">
<UserControl.Resources>
<ObjectDataProvider
x:Key="EnumDescription"
MethodName="GetValues"
ObjectType="{x:Type enums:Filter}">
<ObjectDataProvider.MethodParameters>
<x:Type TypeName="enums:Filter" />
</ObjectDataProvider.MethodParameters>
</ObjectDataProvider>
</UserControl.Resources>
...
<ComboBox
Width="100"
DockPanel.Dock="Right"
ItemsSource="{Binding Source={StaticResource EnumDescription}}"
SelectedItem="{Binding SelectedFilter, ElementName=me}"
/>
...
The dependencyproperty behind:
public Filter SelectedFilter
{
get { return (Filter)GetValue(SelectedFilterProperty); }
set { SetValue(SelectedFilterProperty, value); }
}
// Using a DependencyProperty as the backing store for SelectedFilter. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SelectedFilterProperty =
DependencyProperty.Register("SelectedFilter", typeof(Filter), typeof(FooterBar), new PropertyMetadata(Filter.All));
My Binding-Property:
private Filter _filter;
public Filter SelectedFilter
{
get => _filter;
set
{
SetProperty<Filter>(ref _filter, value);
this.WorkTimes = LoadList(_filter);
}
}
The SetProperty-Method from my ViewModelBase:
protected bool SetProperty<T>(ref T backingStore, T value, Action onChanged = null, [CallerMemberName] string propertyName = "")
{
if (EqualityComparer<T>.Default.Equals(backingStore, value))
return false;
backingStore = value;
onChanged?.Invoke();
OnPropertyChanged(propertyName);
return true;
}
The enum:
public enum Filter
{
All,
LastWeek,
CurrentWeek,
FromTo
}
It seems as if the getter is working but on changes of the itemsource the setter is never executed.
I am trying to build a custom user control, specifically a custom TextBox that converts the text entered by the user to uppercase as it is typed and displays it in the control. However, I cannot get this to work. Here is my code:
CustomTextBox UserControl:
<UserControl x:Class="SOFWpf.CustomTextBox"
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:converters="clr-namespace:SOFWpf.Converters"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<UserControl.Resources>
<converters:CaseConverter x:Key="CaseConverter" />
</UserControl.Resources>
<TextBox Text="{Binding Path=., Converter={StaticResource CaseConverter}}"/>
UserControl's Code-Behind:
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(CustomTextBox), new UIPropertyMetadata(""));
Usage:
<local:CustomTextBox Text="a b c"/>
Converter:
public class CaseConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string text = value as string;
return text?.ToUpper();
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string text = value as string;
return text?.ToLower();
}
}
What do I need to change to make this custom TextBox work as intended?
You need to add binding Path=Text:
<TextBox Text="{Binding Path=Text, Converter={StaticResource CaseConverter}}"/>
And in the user control constructor set DataContext to this:
public CustomTextBox()
{
InitializeComponent();
DataContext = this;
}
A have read a lot of method about the ways of binding enum to combobox. So now in .Net 4.5 it should be pretty ease. But my code dont work.
Dont really understand why.
xaml:
<Window x:Class="SmartTrader.Windows.SyncOfflineDataWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="SyncOfflineDataWindow" Height="300" Width="300">
<Grid>
<StackPanel>
<ComboBox ItemsSource="{Binding StrategyTypes}" SelectedItem="{Binding StrategyType}" />
<Button Width="150" Margin="5" Padding="5" Click="Button_Click">Save</Button>
</StackPanel>
</Grid>
xaml.cs backend
namespace SmartTrader.Windows
{
/// <summary>
/// Interaction logic for SyncOfflineDataWindow.xaml
/// </summary>
public partial class SyncOfflineDataWindow : Window
{
public SyncOfflineDataWindow(IPosition position, ContractType type)
{
DataContext = new ObservablePosition(position);
InitializeComponent();
}
private void Button_Click(object sender, RoutedEventArgs e)
{
}
}
}
View Model:
namespace SmartTrader.Entity
{
public class ObservablePosition : NotifyPropertyChanged, IPosition
{
public IEnumerable<StrategyType> StrategyTypes =
Enum.GetValues(typeof (StrategyType)).Cast<StrategyType>();
public ObservablePosition(IPosition position)
{
Strategy = position.Strategy;
}
private StrategyType _strategyType = StrategyType.None;
public StrategyType Strategy
{
get { return _strategyType; }
set
{
_strategyType = value;
OnPropertyChanged();
}
}
}
}
StrategyType is enum.
All i have got it is empty dropdown list
You are trying to bind to a private variable, instead, your enum should be exposed as a Property.
public IEnumerable<StrategyTypes> StrategyTypes
{
get
{
return Enum.GetValues(typeof(StrategyType)).Cast<StrategyType>();
}
}
Also, Discosultan has already solved another problem for you.
Simplest way to bind any enum data to combobox in wpf XAML:
Add data provider in window or user control resource
xmlns:pro="clr-namespace:TestProject">
<UserControl.Resources>
<ObjectDataProvider x:Key="getDataFromEnum" MethodName="GetValues" ObjectType="{x:Type System:Enum}">
<ObjectDataProvider.MethodParameters>
<x:Type TypeName="pro:YourEnumName"/>
</ObjectDataProvider.MethodParameters>
</ObjectDataProvider>
</UserControl.Resources>
<!--ComboBox xaml:-->
<ComboBox ItemsSource="{Binding Source={StaticResource getDataFromEnum}}"/>
I have found a solution on youtube. Check the link below:
How to Bind an Enum to a ComboBox in WPF: https://youtu.be/Bp5LFXjwtQ0
This solution creates a new class derived from MarkupExtension class and uses this class as a source in the XAML code.
EnumBindingSourceExtention.cs file:
namespace YourProject.Helper
{
public class EnumBindingSourceExtention : MarkupExtension
{
public Type EnumType { get; private set; }
public EnumBindingSourceExtention(Type enumType)
{
if (enumType == null || !enumType.IsEnum)
{
throw new Exception("EnumType is null or not EnumType");
}
this.EnumType = enumType;
}
public override object ProvideValue(IServiceProvider serviceProvider)
{
return Enum.GetValues(EnumType);
}
}
}
View.Xaml file:
<Window
xmlns:helper="clr-namespace:YourProject.Helper"/>
<ComboBox
ItemsSource="{Binding Source={helper:EnumBindingSourceExtention {x:Type local:TheEnumClass}}}" />
local:TheEnumClass: TheEumClass should be located where you specify the namespace (in this case, it is on local)
I have a boolean property (that does called INotifyPropertyChanged in the setter) that is bound to a button.IsEnabled property in my XAML. Currently I'm using a TwoWay binding, but this is causing problems and I only need a OneWay binding. My problem is that the converter I'm using doesn't get called beyond the first time the program starts up. I've put breakpoints in the setter and it gets called loads, but the Convert() method doesn't get called at all. Why is this?
Some code:
public bool IsSaving
{
get
{
return _isSaving;
}
set
{
_isSaving = value;
NotifyOfPropertyChange(() => IsSaving);
}
}
and the XAML:
IsEnabled="{Binding Path=IsSaving, Mode=OneWay, Converter={StaticResource booleanToNotEnabledConverter}}"
The converter really just returns !(bool)value so the button gets disabled when IsSaving is true.
Some changes at runtime might cause the binding to break (since you bind to the DataContext + a relative path), if you use Visual Studio make sure to check the Output-window for any binding errors.
Edit: Since it has not been noted: That is a stardard binding and there is nothing wrong with the posted code, the problem has to be caused by the context.
Here is the code I used and this works:
Converter:
using System.Windows.Data;
using System;
namespace SilverlightApplication1
{
public class BooleanToNotEnabledConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return !(bool)value;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
}
XAML:
<UserControl x:Class="SilverlightApplication1.MainPage"
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:SilverlightApplication1"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<UserControl.Resources>
<local:BooleanToNotEnabledConverter x:Key="booleanToNotEnabledConverter" />
</UserControl.Resources>
<StackPanel Margin="100">
<Button Content="Flip"
Click="Button_Click" />
<TextBlock Text="{Binding IsSaving}"
Height="20" />
<Button IsEnabled="{Binding IsSaving, Mode=OneWay, Converter={StaticResource booleanToNotEnabledConverter}}"
Content="Some Button" />
</StackPanel>
</UserControl>
Code behind:
using System.Windows.Controls;
using System.Windows;
using System.ComponentModel;
namespace SilverlightApplication1
{
public partial class MainPage : UserControl
{
private Data _data;
public MainPage()
{
InitializeComponent();
_data = new Data { IsSaving = true };
this.DataContext = _data;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
_data.IsSaving = !_data.IsSaving;
}
}
public class Data : INotifyPropertyChanged
{
#region IsSaving Property
private bool _isSaving;
public bool IsSaving
{
get
{
return _isSaving;
}
set
{
if (_isSaving != value)
{
_isSaving = value;
OnPropertyChanged("IsSaving");
}
}
}
#endregion
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
var p = PropertyChanged;
if (p != null)
{
p(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
Are you sure you invoke the PropertyChanged event handler with the correct string?
PropertyChanged.Invoke(this, new PropertyChangedEventArgs("IsSaving"));
I have big problem with databinding.
I cant bind data to children control. I'm really newbie in MVVM and I spend a lot of hours at this example and I have no idea what is wrong with this Code.
Little explanation:
I have MainWindow. It has UserControl to display list of todo.
I want to set my MyWindow class ParentViewModel as DataContext.
DataContext has TodoItemModelView as subdatacontext which must be datacontext of UserControlTodoItems.
<Window x:Class="Repo.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Repo="clr-namespace:Repo" Title="Window1" Height="300" Width="300">
<Window.Resources>
<Repo:ParentViewModel x:Key="parentVM"/>
</Window.Resources>
<Window.DataContext>
<StaticResourceExtension ResourceKey="parentVM"/>
</Window.DataContext>
<Grid>
<Repo:UserControlTodoItems DataContext="{Binding Path=todoItemModelView}">
</Repo:UserControlTodoItems>
</Grid>
</Window>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
class ParentViewModel
{
public TodoItemModelView todoItemModelView { get; set; }
public ParentViewModel()
{
this.todoItemModelView=new TodoItemModelView();
}
}
public class TodoItemModelView
{
public ObservableCollection<TodoItem> todoItems { get; set; }
public TodoItemModelView()
{
ObservableCollection<TodoItem> loadedTodoItems = new ObservableCollection<TodoItem>();
loadedTodoItems.Add(new TodoItem() { Code = "10", ObjectCode = "DE", ObjectType = ObjectType.Country, Status = TodoItemStatus.InProgress, Type = TodoItemType.CollectPhotos });
loadedTodoItems.Add(new TodoItem() { Code = "11", ObjectCode = "DE", ObjectType = ObjectType.Country, Status = TodoItemStatus.Todo, Type = TodoItemType.DescribeOjbect });
loadedTodoItems.Add(new TodoItem() { Code = "12", ObjectCode = "DE", ObjectType = ObjectType.Country, Status = TodoItemStatus.Accomplshed, Type = TodoItemType.CollectVideos });
todoItems = loadedTodoItems;
}
}
<UserControl x:Class="Repo.UserControlTodoItems"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Repo="clr-namespace:Repo" Height="auto" Width="auto">
<UserControl.Resources>
<Repo:TodoItemStatusConverter x:Key="TodoItemStatusConverter"/>
</UserControl.Resources>
<Grid>
<ListBox ItemsSource="{Binding Path=todoItems}" Name="lbTasks">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="{Binding Path=Status, Converter={StaticResource TodoItemStatusConverter}}"/>
<TextBlock Text="{Binding Path=Type}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</UserControl>
public UserControlTodoItems()
{
InitializeComponent();
}
I correct this.
I must add one question:
is there any simple way to inform parentmodel, of change checkbox at listbox?
this is a converter:
public class TodoItemStatusConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
TodoItemStatus todoItemStatus = (TodoItemStatus)value;
if (todoItemStatus == TodoItemStatus.Accomplshed)
{
return true;
}
else
{
return false;
}
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
if ((bool) value)
{
return TodoItemStatus.Accomplshed;
}
else
{
return TodoItemStatus.InProgress;
}
}
This is class TodoItem:
public class TodoItem
{
public TodoItemType Type { get; set; }
public TodoItemStatus Status { get; set; }
public string Code { get; set; }
public string ObjectCode { get; set; }
public ObjectType ObjectType { get; set; }
}
Why is the binding for your "lbTasks" Listbox just "{Binding}" and not "{Binding Path=todoItems}"
I'm really taking a quick glance at your code here.. you seem to be passing the todoItemModelView as a DataContext properly, but never inform the listbox where in that data context it will find its items.
You may also want to use an ObservableCollection for the list in the VM so you can add and remove todo's in a way the GUI can respond to
<CheckBox IsChecked="{Binding Path=Status, Converter={StaticResource TodoItemStatusConverter}}"/>
This implies there is a property on ToDoItemViewModel called Status - but there isn't! Rethink your ToDoItemVm class to just be a wrapper for a toDoItem (ie, public ToDoItemVm(ToDoItem model) and get that array of items into the PArentVm (do use ObservableCollection and bind it to the list box. Also add a SelectedToDoItem property on the ParentVm. So your binding for the list box includes something like
ItemsSource="{Binding ToDoTems}"
IsSynchronizedWithCurrentItem="True"
SelectedItem="{Binding SelectedToDoItem, Mode=TwoWay}"
Then expose that Status property on your ToDoItemVm, have the class implement INPC, and raise PropertyChanged in the setter.
It may take some work to sort it out, so feel free to ask more questions as you go. The converter idea is fine.
HTH,
Berryl