WPF UserControl Styling - wpf

I'm quite 'green' into WPF and I appreciate if you could share some starting point example or help me fixing my own code.
I have tree UserControl (Component, ComponentTop, ComponentBottom) that share the same ViewModel class 'ComponentViewModel'.
Instead of using this tree UserControl I would like to use just 'Component' to host the Style and DataContext (ComponentViewModel) and create 3 styles (Base,Top and Bottom) and then I just need to set Component.Style to alternate component visualization.
I've try to declare a style in a resource dictionary but the binding doesn't work.
And from the UserControl I can set the style "Style={StaticResource Base}" but after building the project I get error code saying 'Resource not found'.
The Style:
<Style x:Key="Base" TargetType="UserControl">
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<Border BorderThickness="0.5" BorderBrush="Gray">
<Grid>
<Grid.RowDefinitions>
<RowDefinition x:Name="Head" Height="Auto"/>
<RowDefinition x:Name="Content" Height="Auto"/>
</Grid.RowDefinitions>
<Border Grid.Column="0" Margin="1" BorderThickness="0.25" BorderBrush="Black" Background="{Binding StatusColor}">
<Grid HorizontalAlignment="Stretch">
<TextBlock Margin="1,0,1,0" Text="{Binding Name, FallbackValue=######}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<Image HorizontalAlignment="Right" VerticalAlignment="Bottom" Margin="0,0,0,1" Width="10" Height="10" Source="{Binding PriorityImage}" Visibility="{Binding PriorityImageVisibility}"></Image>
</Grid>
</Border>
<Grid Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="auto"/>
</Grid.ColumnDefinitions>
<layout:TagsContainer Margin="2,0,0,0" Grid.Column="0" VerticalAlignment="Top" HorizontalAlignment="Left" DataContext="{Binding TagsContainerDataContext}"/>
<layout:ControlTagsContainer Margin="5,0,2,0" Grid.Column="1" VerticalAlignment="Top" HorizontalAlignment="Left" DataContext="{Binding ControlTagsContainerDataContext}"/>
</Grid>
<Image Grid.Row="1" Grid.RowSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="25" Height="25" MaxHeight="35" MaxWidth="35" Source="{Binding StatusImage}" Visibility="{Binding StatusImageVisibility}" ></Image>
</Grid>
</Border>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
The UserControl:
<UserControl
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:local="clr-namespace:ProjectX.UI.Layout"
xmlns:ViewModels="clr-namespace:ProjectX.UI.Layout.ViewModels"
x:Class="ProjectX.UI.Layout.Component"
mc:Ignorable="d" Cursor="" x:Name="Root" Height="auto" MinHeight="10" MinWidth="10" FontSize="10" Width="auto" Style="{ StaticResource Base }" >
<UserControl.DataContext>
<ViewModels:ComponentViewModel/>
</UserControl.DataContext>
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source= "Components.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>
TheViewModel:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ProjectX.Model.Component;
using DevExpress.Mvvm;
using System.Windows.Media;
using ProjectX.Model.Tag;
using ProjectX.UI.Tag;
using AppContext = ProjectX.Model.Tag.AppContext;
using System.Windows;
using System.Windows.Media.Imaging;
using ProjectX.Model.Component.Components;
namespace ProjectX.UI.Layout.ViewModels
{
public class ComponentViewModel : ViewModelBase
{
private ComponentBase DataModel = new ComponentBase();
public string? Name
{
get { return GetValue<string>(); }
private set { SetValue(value); }
}
public Brush StatusColor
{
get { return GetValue<Brush>(); }
private set { SetValue(value); }
}
public ImageSource StatusImage
{
get { return GetValue<ImageSource>(); }
private set { SetValue(value); }
}
public Visibility StatusImageVisibility
{
get { return GetValue<Visibility>(); }
private set { SetValue(value); }
}
public ImageSource PriorityImage
{
get { return GetValue<ImageSource>(); }
private set { SetValue(value); }
}
public Visibility PriorityImageVisibility
{
get { return GetValue<Visibility>(); }
private set { SetValue(value); }
}
public Visibility SHControlsVisibility
{
get { return GetValue<Visibility>(); }
private set { SetValue(value); }
}
public TagsContainerViewModel TagsContainerDataContext
{
get { return GetValue<TagsContainerViewModel>(); }
private set { SetValue(value); }
}
public ControlTagsContainerViewModel ControlTagsContainerDataContext
{
get { return GetValue<ControlTagsContainerViewModel>();}
private set { SetValue(value); }
}
private List<RuntimeTagViewModel>? Tags = null;
private List<RuntimeTagViewModel>? ControlTags = null;
public ComponentViewModel()
{
Name = "COMPONENT X";
TagsContainerDataContext = new TagsContainerViewModel();
ControlTagsContainerDataContext = new ControlTagsContainerViewModel();
Init();
}
public ComponentViewModel(ComponentBase datamodel)
{
DataModel = datamodel;
Name = datamodel.Label;
Tags = DataModel.Tags.Where(x => x.AppContext == AppContext.Layout && x.Scope == Scope.User).Select(x => new RuntimeTagViewModel(x)).ToList();
ControlTags = DataModel.Tags.Where(x => x.AppContext == AppContext.Control && x.Scope == Scope.User).Select(x => new RuntimeTagViewModel(x)).ToList();
TagsContainerDataContext = new TagsContainerViewModel(Tags);
ControlTagsContainerDataContext = new ControlTagsContainerViewModel(ControlTags);
Init();
}
private void Init()
{
StatusColor = Brushes.Gray;
SetStatusImage(StatusEnum.Warning);
SHControlsVisibility = Visibility.Collapsed;
PriorityImageVisibility = Visibility.Collapsed;
if (DataModel.Interface == nameof(IDamper))
{
PriorityImage = Global.Resources.Images.Priority;
PriorityImageVisibility = Visibility.Visible;
}
if (DataModel.Interface == nameof(ISystemHandler))
{
SHControlsVisibility = Visibility.Visible;
}
}
public void SetStatusImage(StatusEnum status = StatusEnum.None)
{
switch (status)
{
case StatusEnum.None:
StatusImage = Global.Resources.Images.Warning;
break;
case StatusEnum.Error:
StatusImage = Global.Resources.Images.Error;
break;
case StatusEnum.Warning:
StatusImage = Global.Resources.Images.Warning;
break;
case StatusEnum.Info:
StatusImage = Global.Resources.Images.Info;
break;
default:
throw new NotImplementedException();
}
if (status != StatusEnum.None)
{
StatusImageVisibility = Visibility.Visible;
}
else
{
StatusImageVisibility = Visibility.Hidden;
}
}
}
}
Thank you!

If I understood you correctly, your XAML in the Development mode does not issue errors and warnings and works as you expect.
And at runtime, an error occurs due to finding the style you need in the "Components.xaml" file.
The StaticResource is evaluated at the time the element is created. And the Resources collection is filled in and added later. Due to the peculiarities of the designer's work, this error is not always displayed in this mode.
In your case, it will be enough to replace StaticResource with DynamicResourse.

After some time and research I fix the binding problem by using the following syntax:
Background="{Binding DataContext.StatusColor, RelativeSource={RelativeSource AncestorType=layout:Component}}
Instead of original one:
Background="{Binding StatusColor}"

Related

Multiple selection in WPF MVVM ListBox

I have a ListBox containing filenames. Now I need to get array of selected items from this ListBox. I found a few answers here, but none of them worked for me. I'am using Caliburn Micro framework.
Here is my View:
<Window x:Class="ProgramsAndUpdatesDesktop.Views.DeleteHistoryView"
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:ProgramsAndUpdatesDesktop.Views"
mc:Ignorable="d"
ResizeMode="CanResizeWithGrip"
MaxWidth="300"
MinWidth="300"
MinHeight="500"
Title="DeleteHistoryView" Height="500" Width="300">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="30" />
</Grid.RowDefinitions>
<StackPanel Grid.Column="0" Grid.Row="0">
<ListBox x:Name="DeleteHistoryListBox" SelectedItem="{Binding Path=DeleteHistorySelectedItem}"
ItemsSource="{Binding DeleteHistoryListBox, NotifyOnSourceUpdated=True}"
SelectionMode="Multiple">
</ListBox>
</StackPanel>
<StackPanel Grid.Column="0" Grid.Row="1">
<Button x:Name="DeleteHistoryButtonAction">Delete</Button>
</StackPanel>
</Grid>
And here is my ViewModel:
class DeleteHistoryViewModel : Screen
{
string historyFolderPath = Environment.ExpandEnvironmentVariables(ConfigurationManager.AppSettings["HistoryFolderPath"]);
private ObservableCollection<string> deleteHistoryListBox = new ObservableCollection<string>();
public ObservableCollection<string> DeleteHistoryListBox
{
get { return deleteHistoryListBox; }
set { deleteHistoryListBox = value; NotifyOfPropertyChange(() => DeleteHistoryListBox); }
}
private List<string> deleteHistorySelectedItem = new List<string>();
public List<string> DeleteHistorySelectedItem
{
get { return deleteHistorySelectedItem; }
set { deleteHistorySelectedItem = value; }
}
public DeleteHistoryViewModel()
{
base.DisplayName = "Delete History";
}
protected override void OnInitialize()
{
FillListBox();
}
private void FillListBox()
{
string[] directory = Directory.GetFiles($"{historyFolderPath}\\", "*.json");
foreach (var item in directory)
{
string fileName = System.IO.Path.GetFileName(item).ToString();
if (!DeleteHistoryListBox.Contains(fileName))
{
DeleteHistoryListBox.Add(fileName);
}
}
}
#region ACTIONS REGION
// DELETE HISTORY ACTION
public void DeleteHistoryButtonAction()
{
foreach (var item in DeleteHistorySelectedItem)
{
MessageBox.Show(item);
}
}
#endregion
}
You can use this code for MVVM Pattern
XAML
<ListBox x:Name="DeleteHistoryListBoxItem" SelectedItem="{Binding Path=DeleteHistorySelectedItem,UpdateSourceTrigger=PropertyChanged}"
ItemsSource="{Binding DeleteHistoryListBox, NotifyOnSourceUpdated=True}" SelectionMode="Multiple">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Item}"/>
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=IsSelected}"/>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
ViewModel
private ObservableCollection<HistoryItems> deleteHistoryListBox = new ObservableCollection<HistoryItems>();
public ObservableCollection<HistoryItems> DeleteHistoryListBox
{
get
{
return deleteHistoryListBox;
}
set
{
deleteHistoryListBox = value;
this.RaisePropertyChanged("DeleteHistoryListBox");
}
}
private HistoryItems deleteHistorySelectedItem;
public HistoryItems DeleteHistorySelectedItem
{
get
{
return deleteHistorySelectedItem;
}
set
{
var selectedItems = DeleteHistoryListBox.Where(x => x.IsSelected).Count();
this.RaisePropertyChanged("DeleteHistorySelectedItem");
}
}
Class
public class HistoryItems : INotifyPropertyChanged
{
private string item;
public string Item
{
get { return item; }
set
{
item = value;
this.RaisePropertyChanged("Item");
}
}
private bool isSelected;
public bool IsSelected
{
get { return isSelected; }
set
{
isSelected = value;
this.RaisePropertyChanged("IsSelected");
}
}
}

wpf listbox resetting selectedIndex when containing grid resizes

I need a composite view consisting of a top part that can be hidden, a bottom part consisting of a navigation menu (listbox) on the left and a content area on the right.
One option in the listbox should make the top-part collapsed and other listoptions should show the top-part.
My idea was to split the screen in top- and bottom part using a grid with three rows (middle row for gridsplitter) and currently Im using codebehind for changing the height of the top grid.
The Problem is that when I set the Grid.Height-prop from codebehind, my ListBox.SelectedIndex is set from 1 to 0 ! Thing is that if I change order of the two menu-items, it works fine!
We are using Caliburn Micro, but I don't think that changes anything - the example could be implemented with INotifyPropertyChanged as well.
<UserControl x:Uid="UserControl_1" x:Class="VisionAir.Client.Gui.Common.Windows.Foo.Views.BarView"
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"
mc:Ignorable="d" Height="300" Width="300">
<UserControl.Resources>
<ResourceDictionary>
<BooleanToVisibilityConverter x:Key="BoolToVisConverter"/>
</ResourceDictionary>
</UserControl.Resources>
<Grid Name="ResizableGrid">
<Grid.RowDefinitions>
<RowDefinition Height="100" Name="TopRow"/>
<RowDefinition Height="10" Name="SplitterRow"/>
<RowDefinition Name="BottomRow"/>
</Grid.RowDefinitions>
<Grid Grid.Row="0" Name="TopRowGrid" Background="Chartreuse" Visibility="{Binding ShowSearchView, Converter={StaticResource BoolToVisConverter}}"/>
<GridSplitter Grid.Row="1" Visibility="{Binding ShowSearchView,Converter={StaticResource BoolToVisConverter}}" ResizeBehavior="PreviousAndCurrent" HorizontalAlignment="Stretch" Height="10"/>
<Grid Name="ListGrid" Grid.Row="2">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<ListBox Grid.Column="0" ItemsSource="{Binding Items}" SelectedIndex="{Binding SelectedIndex}" DisplayMemberPath="DisplayName">
</ListBox>
<Grid Background="Chocolate" Grid.Column="1"/>
</Grid>
<Canvas Name="FooCanvas" Visibility="{Binding ShowSearchView, Converter={StaticResource BoolToVisConverter}}"></Canvas>
</Grid>
</UserControl>
using System.Windows;
using System.Windows.Controls;
namespace VisionAir.Client.Gui.Common.Windows.Foo.Views
{
/// <summary>
/// Interaction logic for BarView.xaml
/// </summary>
public partial class BarView : UserControl
{
public BarView()
{
InitializeComponent();
FooCanvas.IsVisibleChanged += FooCanvas_IsVisibleChanged;
}
void FooCanvas_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
bool isVisible = (bool)e.NewValue;
if (isVisible)
{
TopRow.Height = new GridLength(100);
SplitterRow.Height = new GridLength(0, GridUnitType.Auto);
}
else
{
TopRow.Height = new GridLength(0, GridUnitType.Auto);
SplitterRow.Height = new GridLength(0);
}
}
}
}
using System.Collections.Generic;
using Caliburn.Micro;
namespace VisionAir.Client.Gui.Common.Windows.Foo.ViewModels
{
public class BarViewModel : PropertyChangedBase
{
private List<Screen> _items = new List<Screen>();
public BarViewModel()
{
Items.Add(new Screen() { DisplayName = "Hide" });
Items.Add(new Screen() { DisplayName = "Show" });
}
public bool ShowSearchView { get { return SelectedIndex == 1; } }
private int _selectedIndex;
public List<Screen> Items
{
get { return _items; }
set { _items = value; }
}
public int SelectedIndex
{
get { return _selectedIndex; }
set
{
System.Diagnostics.Debug.WriteLine(value);
_selectedIndex = value;
NotifyOfPropertyChange(() => ShowSearchView);
}
}
}
}

WPF Control losing focus when clicking on a tab

On a tabcontrol I have several tabpages, on one of the tabs there is a textbox in the content.
This textbox is content bound with a simple Path=PropertyName and UpdateSourceTrigger=LostFocus. The reason I am using LostFocus is I trap the Lost focus event of the Textbox and possibly reformat the text. This is a "time" textbox and if they enter "0900", I want to reformat to "09:00". This part works great when I press the tab key to move to the next control, but if I type "0900" then press one of the other tabs, I hit the lost focus and re-format the value in the textbox, BUT the bind never gets called to update my object. When I come back to the tab, the value is blanked out (or reset to the original value on the object)
Any ideas why textbox does not trigger the Binding update when changing tab page?
Note: this also happens with a regular textbox that does wire to the lost focus event. It seems to have something to do with click on the tab.
[[Added Code ]]
More notes:
1. I am dynamically creating the tabs and controls on the tab (not sure if that has something to do with it or not)
2. I am using the Prism libraries
MainWindow Xaml
<Window.Resources>
<DataTemplate DataType="{x:Type ctrls:myTextBoxDef}">
<Grid Width="300">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" MinWidth="100" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="28" />
</Grid.RowDefinitions>
<TextBlock Grid.Column="0"
HorizontalAlignment="Stretch"
VerticalAlignment="Center"
Text="{Binding LabelText}" />
<TextBox Grid.Column="1"
HorizontalAlignment="Stretch"
VerticalAlignment="Center"
Text="{Binding DocValue,
Mode=TwoWay,
ValidatesOnDataErrors=True,
UpdateSourceTrigger=LostFocus}"
/>
</Grid>
</DataTemplate>
</Window.Resources>
<Grid>
<TabControl HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
HorizontalContentAlignment="Stretch"
VerticalContentAlignment="Stretch"
IsTabStop="False"
ItemsSource="{Binding Tabs, Mode=OneWay}"
SelectedItem="{Binding SelectedTab,
Mode=TwoWay,
NotifyOnSourceUpdated=True}"
>
<TabControl.ItemTemplate>
<DataTemplate>
<Grid>
<TextBlock Margin="18,14,22,0"
Text="{Binding HeaderText}" />
</Grid>
</DataTemplate>
</TabControl.ItemTemplate>
<!-- Content -->
<TabControl.ContentTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<AdornerDecorator Grid.Column="0">
<ItemsControl Grid.Column="0"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
IsTabStop="False"
ItemsSource="{Binding Controls,
Mode=OneWay}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Grid.Column="0"
Margin="10,5,0,0"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Orientation="Vertical" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</AdornerDecorator>
</Grid>
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
</Grid>
</Window>
Main Window Code Behind
public partial class MainWindow : Window
{
private DataContextObject obj = new DataContextObject();
public MainWindow()
{
InitializeComponent();
myTextBoxDef txt1 = new myTextBoxDef(obj, "Textbox 1", "TAB1TextBox1");
myTextBoxDef txt1b = new myTextBoxDef(obj, "Textbox 1 value", "TAB1TextBox1");
myTextBoxDef txt2 = new myTextBoxDef(obj, "Textbox 2", "TAB1TextBox2");
myTextBoxDef txt2b = new myTextBoxDef(obj, "Textbox 2 value", "TAB1TextBox2");
obj.Tabs.Add(new myTabDef("Tab 1", new ObservableCollection<myTextBoxDef>() { txt1, txt2 }));
obj.Tabs.Add(new myTabDef("Tab 2", new ObservableCollection<myTextBoxDef>() { txt1b, txt2b }));
obj.SelectedTab = obj.Tabs[0];
this.DataContext = obj;
}
}
Supporting objects
public class DataContextObject : NotificationObject
{
List<myTabDef> _tabs = new List<myTabDef>();
public List<myTabDef> Tabs
{
get
{
return _tabs;
}
}
private myTabDef _item;
public myTabDef SelectedTab
{
get
{ return _item; }
set
{
_item = value;
this.RaisePropertyChanged("SelectedItem");
}
}
private string _txt1 = "";
public string TAB1TextBox1
{
get { return _txt1; }
set
{
_txt1 = value;
this.RaisePropertyChanged("TAB1TextBox1");
}
}
private string _txt2 = "";
public string TAB1TextBox2
{
get { return _txt2; }
set
{
_txt2 = value;
this.RaisePropertyChanged("TAB1TextBox2");
}
}
private string _txt3 = "";
public string TAB2TextBox1
{
get { return _txt3; }
set
{
_txt3 = value;
this.RaisePropertyChanged("TAB2TextBox1");
}
}
}
public class myTabDef
{
public myTabDef(string tabText, ObservableCollection<myTextBoxDef> controls)
{
HeaderText = tabText;
_left = controls;
}
public string HeaderText { get; set; }
private ObservableCollection<myTextBoxDef> _left = new ObservableCollection<myTextBoxDef>();
public ObservableCollection<myTextBoxDef> Controls
{
get
{
return _left;
}
}
}
public class myTextBoxDef : NotificationObject
{
public myTextBoxDef(NotificationObject bound, string label, string bindingPath)
{
LabelText = label;
Path = bindingPath;
BoundObject = bound;
BoundObject.PropertyChanged += BoundObject_PropertyChanged;
}
public string LabelText
{
get;
set;
}
public NotificationObject BoundObject
{
get;
set;
}
public string DocValue
{
get
{
return PropInfo.GetValue(BoundObject, null) as string;
}
set
{
PropInfo.SetValue(BoundObject, value, null);
}
}
protected virtual void BoundObject_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (e.PropertyName.Equals(Path))
{
this.RaisePropertyChanged("DocValue");
}
}
public string Path
{
get;
set;
}
private PropertyInfo pi = null;
protected PropertyInfo PropInfo
{
get
{
if (pi == null && BoundObject != null && !string.IsNullOrEmpty(Path))
{
PropertyInfo[] properties = BoundObject.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);
pi = properties.Where((prop) => string.Compare(prop.Name, Path, true) == 0).FirstOrDefault();
}
return pi;
}
}
}
We have found a solution. I came cross this set of postings
https://groups.google.com/forum/#!topic/wpf-disciples/HKUU61A5l74
They talk about a control called TabControlEx. Towards the bottom (5th from the bottom) you will see a posting by Sacha Barber that has a zip file with an example.
It solved all our problems we were having.
here is also another link where the code for the Class is posted
http://updatecontrols.codeplex.com/discussions/214434

Trouble with DataBinding to a ListBox in WP7 which is not displaying the bound content

I have a DataBinding on a ListBox, bound to an ObservableCollection. Debugging at runtime shows the ObservableCollection does have items in it, and they're not null. My code all looks fine, however for some reason nothing is being displayed in my ListBox. It definitely was working previously, however it no longer is - and I can't figure out why. I've examined previous versions of the code and found no differences that would have any effect on this - minor things like Width="Auto" etc.
I based my code off of the example found here:
http://msdn.microsoft.com/en-us/library/hh202876.aspx
So, my code:
XAML:
<phone:PhoneApplicationPage
x:Class="MyNamespace.MyItemsListPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneForegroundBrush}"
SupportedOrientations="Portrait" Orientation="Portrait"
mc:Ignorable="d" d:DesignHeight="768" d:DesignWidth="480"
shell:SystemTray.IsVisible="True">
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<TextBlock Grid.Row="0" x:Name="PageTitle" Text="MyPageTitle" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<!-- Bind the list box to the observable collection. -->
<ListBox x:Name="myItemsListBox" ItemsSource="{Binding MyItemsList}" Margin="12, 0, 12, 0" Width="440">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid HorizontalAlignment="Stretch" Width="440">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="80" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<TextBlock
Text="{Binding MyItemNumber}"
FontSize="{StaticResource PhoneFontSizeLarge}"
Grid.Column="0"
VerticalAlignment="Center"
Margin="0,10"
Tap="TextBlock_Tap"/>
<TextBlock
Text="{Binding MyItemName}"
FontSize="{StaticResource PhoneFontSizeLarge}"
Grid.Column="1"
VerticalAlignment="Center"
Margin="0,10"
Tap="TextBlock_Tap" />
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Grid>
</phone:PhoneApplicationPage>
C#:
namespace MyNamespace
{
public partial class MyItemsListPage : PhoneApplicationPage, INotifyPropertyChanged
{
private static ObservableCollection<MyItem> _myItemsList;
private ObservableCollection<MyItem> MyItemsList
{
get
{
return _myItemsList;
}
set
{
if (_myItemsList!= value)
{
_myItemsList= value;
NotifyPropertyChanged("MyItemsList");
}
}
}
public MyItemsListPage ()
{
InitializeComponent();
this.DataContext = this;
}
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
HelperClass helper = new HelperClass();
MyItemsList = helper.GetItems(this.NavigationContext.QueryString["query"]);
base.OnNavigatedTo(e); // Breakpoint here shows "MyItemsList" has MyItem objects in it.
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
// Used to notify Silverlight that a property has changed.
private void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
}
}
The Helper class is a connector to my read-only local database on the device. It returns an ObservableCollection<MyItem>:
public ObservableCollection<MyItem> GetItems(string itemName)
{
// Input validation etc.
// Selecting all items for testing
var itemsInDB =
from MyItem item in db.Items
select item;
return new ObservableCollection<MyItem>(itemsInDB);
}
And finally the MyItem class:
[Table]
public class MyItem: INotifyPropertyChanged, INotifyPropertyChanging
{
private int _myItemId;
[Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)]
public int MyItemId
{
...
}
private string _myItemName;
[Column(CanBeNull = false)]
public string MyItemName
{
get
{
return _myItemName;
}
set
{
if (_myItemName!= value)
{
NotifyPropertyChanging("MyItemName");
_myItemName= value;
NotifyPropertyChanged("MyItemName");
}
}
}
private int _myItemNumber;
[Column]
public int MyItemNumber
{
get
{
return _myItemNumber;
}
set
{
if (_myItemNumber!= value)
{
NotifyPropertyChanging("MyItemNumber");
_myItemNumber= value;
NotifyPropertyChanged("MyItemNumber");
}
}
}
// Other properties, NotifyPropertyChanged method, etc...
}
This is rather frustrating as my DataBinding elsewhere in the application is working perfectly, so I've no idea why I can't get this to work.
The problem was that my ObservableCollection was private. Changing it to have a public access modifier allowed my ListBox to display the contents:
public ObservableCollection<MyItem> MyItemsList
Simply that you're binding to properties named incorrectly:
Text="{Binding ItemName}" should be Text="{Binding MyItemName}"
Notice you left out "My"

Dynamic template wpf

i have made a template that look like this :
<ControlTemplate x:Key="onoffValue" TargetType="{x:Type Control}">
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Height="20" Margin="0,5,0,0">
<RadioButton Content="On" Height="20" Name="On_radiobutton" />
<RadioButton Content="Off" Height="20" Name="Off_radiobutton" Margin="20,0,0,0" />
</StackPanel>
<ControlTemplate.Triggers>
<DataTrigger Binding="{Binding Path=BootSector}" Value="true">
<Setter TargetName="On_radiobutton" Property="IsChecked" Value="true"/>
</DataTrigger>
<DataTrigger Binding="{Binding Path=BootSector}" Value="false">
<Setter TargetName="Off_radiobutton" Property="IsChecked" Value="true"/>
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
For now, it is bind to the property BootSector(bool) ofa "Configuration" object.
I use this template in my window that has a configuration object as data context like this :
<Control Template="{StaticResource onoffValue}">
</Control>
It works great, but i want to go further.
I would like to know how i can pass a different property to my template to dynamically bind (dynamically change the property the template is bind to)
ie i tryed something like
<Control Template="{StaticResource onoffValue}" xmlns:test="{Binding Path=BootSector}"/>
and bind it in the template to "test" but it doesn't work
Is it possible ? How can i do that ? I think i'm not too far away but not there still !
Thank you in advance
Edit : Concerning Dmitry answer :
There is a bug using that. When i do :
<StackPanel local:ToggleControl.IsOn="{Binding BootSector, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
Grid.Row="0" Grid.Column="1"
Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<RadioButton Content="On" local:ToggleControl.Role="On" Height="20" Margin="5" />
<RadioButton Content="Off" local:ToggleControl.Role="Off" Height="20" Margin="5" />
</StackPanel>
By default BootSector is on false. When i click on the on button (true), it sets bootSector to true and then immediately to false . The behaviour should be that it stays to true until it is unchecked ? Is this related to the problem related here ? http://geekswithblogs.net/claraoscura/archive/2008/10/17/125901.aspx
Here, the idea is - generic behaviors are never complex and generally not worth creating a custom control. I undertand that implmentation may vary, but the approach will remain the same. It makes sense to use XAML for the parts which can change and code for the stuff which will remain constant.
UPDATE 1- It's getting even easier when using Custom controls. You won't need attached property no more - as you'll get a dedicated space for it inside your custom control, also, you can use x:Name and GetTemplateChild(..) to otain a reference to individual RadioButtons.
Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.ComponentModel;
namespace RadioButtons
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.Loaded += (o, e) =>
{
this.DataContext = new TwoBoolean()
{
PropertyA = false,
PropertyB = true
};
};
}
private void Button_Click(object sender, RoutedEventArgs e)
{
MessageBox.Show(((TwoBoolean)this.DataContext).ToString());
}
}
public enum RadioButtonRole
{
On,
Off
}
public class ToggleControl : DependencyObject
{
public static readonly DependencyProperty IsOnProperty =
DependencyProperty.RegisterAttached("IsOn",
typeof(bool?),
typeof(ToggleControl),
new PropertyMetadata(null,
new PropertyChangedCallback((o, e) =>
{
ToggleControl.OnIsOnChanged((Panel)o, (bool)e.NewValue);
})));
public static readonly DependencyProperty RoleProperty =
DependencyProperty.RegisterAttached("Role",
typeof(RadioButtonRole?),
typeof(ToggleControl),
new PropertyMetadata(null,
new PropertyChangedCallback((o, e) =>
{
})));
private static readonly DependencyProperty IsSetUpProperty =
DependencyProperty.RegisterAttached("IsSetUp",
typeof(bool),
typeof(ToggleControl),
new PropertyMetadata(false));
private static void OnIsOnChanged(Panel panel, bool e)
{
if (!ToggleControl.IsSetup(panel))
{
ToggleControl.Setup(panel);
}
RadioButtonRole role;
if (e)
{
role = RadioButtonRole.On;
}
else
{
role = RadioButtonRole.Off;
}
ToggleControl.GetRadioButtonByRole(role, panel).IsChecked = true;
}
private static void Setup(Panel panel)
{
// get buttons
foreach (RadioButton radioButton in
new RadioButtonRole[2]
{
RadioButtonRole.On,
RadioButtonRole.Off
}.Select(t =>
ToggleControl.GetRadioButtonByRole(t, panel)))
{
radioButton.Checked += (o2, e2) =>
{
RadioButton checkedRadioButton = (RadioButton)o2;
panel.SetValue(ToggleControl.IsOnProperty,
ToggleControl.GetRadioButtonRole(checkedRadioButton) == RadioButtonRole.On);
};
}
panel.SetValue(ToggleControl.IsSetUpProperty, true);
}
private static bool IsSetup(Panel o)
{
return (bool)o.GetValue(ToggleControl.IsSetUpProperty);
}
private static RadioButton GetRadioButtonByRole(RadioButtonRole role,
Panel container)
{
return container.Children.OfType<RadioButton>().First(t =>
(RadioButtonRole)t.GetValue(ToggleControl.RoleProperty) == role);
}
private static RadioButtonRole GetRadioButtonRole(RadioButton radioButton)
{
return (RadioButtonRole)radioButton.GetValue(ToggleControl.RoleProperty);
}
public static void SetIsOn(DependencyObject o, bool? e)
{
o.SetValue(ToggleControl.IsOnProperty, e);
}
public static bool? GetIsOn(DependencyObject e)
{
return (bool?)e.GetValue(ToggleControl.IsOnProperty);
}
public static void SetRole(DependencyObject o, RadioButtonRole? e)
{
o.SetValue(ToggleControl.RoleProperty, e);
}
public static RadioButtonRole? GetRole(DependencyObject e)
{
return (RadioButtonRole?)e.GetValue(ToggleControl.RoleProperty);
}
}
public class TwoBoolean: INotifyPropertyChanged
{
private bool propertyA, propertyB;
public bool PropertyA
{
get
{
return this.propertyA;
}
set
{
this.propertyA = value;
this.OnPropertyChanged("PropertyA");
}
}
public bool PropertyB
{
get
{
return this.propertyB;
}
set
{
this.propertyB = value;
this.OnPropertyChanged("PropertyB");
}
}
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this,
new PropertyChangedEventArgs(propertyName));
}
}
public override string ToString()
{
return string.Format("PropertyA:{0}, PropertyB:{1}", this.PropertyA, this.PropertyB);
}
public event PropertyChangedEventHandler PropertyChanged;
}
}
Markup:
<Window x:Class="RadioButtons.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:RadioButtons"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Margin="5" VerticalAlignment="Center">PropertyA</TextBlock>
<StackPanel local:ToggleControl.IsOn="{Binding PropertyA, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
Grid.Row="0" Grid.Column="1"
Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<RadioButton Content="On" local:ToggleControl.Role="On" Height="20" Margin="5" />
<RadioButton Content="Off" local:ToggleControl.Role="Off" Height="20" Margin="5" />
</StackPanel>
<TextBlock Grid.Row="1" Grid.Column="0" Margin="5" VerticalAlignment="Center">PropertyB</TextBlock>
<StackPanel local:ToggleControl.IsOn="{Binding PropertyB, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
Grid.Row="1" Grid.Column="1"
Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<RadioButton Content="On" local:ToggleControl.Role="On" Height="20" Margin="5" />
<RadioButton Content="Off" local:ToggleControl.Role="Off" Height="20" Margin="5" />
</StackPanel>
<Button Click="Button_Click" Grid.Row="3" Grid.ColumnSpan="2">Save</Button>
</Grid>
</Window>
You should not use an xmlns to pass a parameter, rather use the Tag or template a ContentControl, then you can bind the Content to your property (set it to TwoWay) and use a TemplateBinding to Content inside the template.

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