We Keep Coding

Multiple Views for a single ViewModel

Issue
I have a number of buttons in my WPF Window which when clicked need to change the view on the Window but keep the same ViewModel. Yesterday I tried using ControlTemplate for this but people mentioned I was better using a DataTemplate.
I need the binding to happen Via the ViewModel as well as I need to do some checks to see if the user can access the view.
Code
This is some of the code i started to write but I feel like its incorrect.
Here is the DataTemplate that I have defined in my view in Window.Resources:
<DataTemplate x:Key="panel1">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="7*"/>
<ColumnDefinition Width="110*"/>
<ColumnDefinition Width="190*"/>
<ColumnDefinition Width="110*"/>
<ColumnDefinition Width="202*"/>
<ColumnDefinition Width="109*"/>
<ColumnDefinition Width="7*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="74*"/>
<RowDefinition Height="50*"/>
<RowDefinition Height="12*"/>
<RowDefinition Height="39*"/>
<RowDefinition Height="11*"/>
<RowDefinition Height="38*"/>
<RowDefinition Height="5*"/>
</Grid.RowDefinitions>
<StackPanel Grid.Column="2" Grid.ColumnSpan="3" Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center">
<Label Content="Video Set:" Foreground="#e37e6e" Grid.Column="2" Grid.ColumnSpan="3" VerticalAlignment="Center" FontSize="22" HorizontalAlignment="Center"/>
<Image Source="{Binding VideoSet}" Height="25" Width="25" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</StackPanel>
<TextBlock Foreground="#e37e6e" FontSize="12" Text="You currently do not have a video set. Please click the button below to add a video. Please note you will not be able to create an On Demand presentation without a media file selected. " Grid.Row="1" Grid.Column="2" TextWrapping="WrapWithOverflow" TextAlignment="Center" Grid.ColumnSpan="3" />
<Button Style="{StaticResource loginButton}" Command="{Binding ScreenBack}" Foreground="White" Content="Add Video" Grid.Column="3" HorizontalAlignment="Stretch" Grid.Row="3" VerticalAlignment="Stretch" Grid.ColumnSpan="1"></Button>
</Grid>
</DataTemplate>
Then I tried to use a ContentPresenter and bind to the DataTemplate:
<ContentPresenter Content="{Binding}" Grid.Row="3" Grid.RowSpan="1" Grid.ColumnSpan="5"/>
Now I want to be able to bind different DataTemplates to the ContentPresenter Via the ViewModel, can anyone help me with this issue?
EDIT:
I can bind the ContentPresenter to the DataTemplate through the static resource like below:
<ContentPresenter ContentTemplate="{StaticResource panel1}" Content="{StaticResource panel1}" Grid.Row="3" Grid.RowSpan="1" Grid.ColumnSpan="5"/>
The DataTemplate like below:
<DataTemplate x:Key="panel1">
</DataTemplate>
But how can i change the ControlPresenter binding from the ViewModel?
EDIT:
Here is my code cycle:
So here are the two DataTemplates:
<DataTemplate DataType="{x:Type local:ViewModelA}">
<TextBlock Foreground="#e37e6e" FontSize="12" Text="You currently do not have a video set. Please click the button below to add a video. Please note you will not be able to create an On Demand presentation without a media file selected. " Grid.Row="1" Grid.Column="2" TextWrapping="WrapWithOverflow" TextAlignment="Center" Grid.ColumnSpan="3" />
</DataTemplate>
<DataTemplate DataType="{x:Type local:ViewModelB}">
<TextBlock Foreground="#e37e6e" FontSize="12" Text="NEWWWWWWWWWWYou" Grid.Row="1" Grid.Column="2" TextWrapping="WrapWithOverflow" TextAlignment="Center" Grid.ColumnSpan="3" />
</DataTemplate>
The my ContentControl:
<ContentControl Content="{Binding SelectedViewModel}" />
I defined my DataContext in the code behind:
WizardViewModel _wizardViewModel = new WizardViewModel();
this.DataContext = _wizardViewModel;
In the WizardViewModel i have:
namespace Podia2016.ViewModels
{
public class WizardViewModel : INotifyPropertyChanged
{
public object SelectedViewModel { get; set; }
ViewModelA s = new ViewModelA();
ViewModelB d = new ViewModelB();
public WizardViewModel()
{
SelectedViewModel = s;
OnPropertyChanged("SelectedViewModel");
}
//BC - BINDS TO CHANGE LECTURE.
public ICommand Next
{
get { return new DelegateCommand<object>(Next_Click); }
}
private void Next_Click(object obj)
{
SelectedViewModel = d;
OnPropertyChanged("SelectedViewModel");
}
}
public class ViewModelA : INotifyPropertyChanged
{
//BC - DEFAULT ONPROPERTYCHANGED EVENT.
public event PropertyChangedEventHandler PropertyChanged;
public ViewModelA()
{
}
/// <summary>
/// This is the standard OnPropertyChanged Event Method
/// </summary>
/// <param name="name"></param>
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
public class ViewModelB : INotifyPropertyChanged
{
//BC - DEFAULT ONPROPERTYCHANGED EVENT.
public event PropertyChangedEventHandler PropertyChanged;
public ViewModelB()
{
}
/// <summary>
/// This is the standard OnPropertyChanged Event Method
/// </summary>
/// <param name="name"></param>
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
}

Data templating is much simpler to use (compared to your attempt):
create sub viewmodels, one for each sub view you want to have
// could have base class, may have to implement INotifyPropertyChanged, etc.
public class ViewModelA { }
public class ViewModelB
{
public string SomeProperty { get; }
}
...
public object SelectedViewModel { get; set; }
define data templates
<SomeContainer.Resources>
<!-- using user control -->
<DataTemplate DataType="{x:Type local:ViewModelA}">
<local:UserControlA />
</DataTemplate>
<!-- or like this -->
<DataTemplate DataType="{x:Type local:ViewModelB}">
<Grid>
<TextBlock Text="{Binding SomeProperty}" />
<Button .../>
...
</Grid>
</DataTemplate>
Bind content control to a property which select sub viewmodel
<ContentControl Content="{Binding SelectedViewModel}" />
control what to display by changing selected sub viewmodel:
var a = new ViewModelA();
var b = new ViewModelB() { SomeProperty = "Test" };
// display a - will display UserControlA content in ContentControl
SelectedViewModel = a;
OnPropertyChanged(nameof(SelectedViewModel));
// display b - will display text and button in ContentControl
SelectedViewModel = b;
OnPropertyChanged(nameof(SelectedViewModel));

Store DataTemplate as property of your ViewModel. Access the DataTemplate from ResourceDictionary to store in your property.
Bind <ContentPresenter Content="{Binding}" ContentTemplate="{Binding template1}" .../>
How to access ResourceDictionary from code :
If you have in your WPF project an ResourceDictionary that you use to define resources you can create an instance of it from code like this:
ResourceDictionary res = Application.LoadComponent(
new Uri("/WpfApplication1;component/MyDataTemplateCollection.xaml",
UriKind.RelativeOrAbsolute)) as ResourceDictionary;
Where WpfApplication1 is name of your assembly and MyDataTemplateCollection.xaml is name of your ResourceDictionary.
Another way is to use the code-behind for the resource dictionary.
Add x:Class to your ResourceDictionary:
Add class MyDataTemplateCollection.xaml.cs as your code-behind for the ResourceDictionary.
The code behind class looks like so:
partial class MyDataTemplateCollection: ResourceDictionary
{
public MyDataTemplateCollection()
{
InitializeComponent();
}
}
Usage :
ResourceDictionary res = new MyDataTemplateCollection();

How do I get WPF Grid columns defined with star to clip content?

I have a Grid control that is proportioned using star e.g.
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50*" />
<ColumnDefinition Width="100*" />
<ColumnDefinition Width="50*" />
</Grid.ColumnDefinitions>
However putting a long TextBlock in the grid that overflows causes the proportions to be upset. e.g.
<TextBlock Text="Foo" Grid.Column="0" />
<TextBlock Text="Some long text here which overflows" Grid.Column="1" />
<TextBlock Text="Foo" Grid.Column="2" />
This causes the central column to be more than double the other two. How do I maintain the specified proportions? Is it possible to clip the content?
I have set TextTrimming="CharacterEllipsis" on the TextBlocks but no luck.
Edit
Crucially it seems, the Grid is inside a DataTemplate, paste the following to observe the behaviour,
<!-- FallbackValue is just a quick hack to get some rows to show at design-time -->
<ListBox ItemsSource="{Binding Foo, FallbackValue=1234}"
HorizontalContentAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50*" />
<ColumnDefinition Width="100*" />
<ColumnDefinition Width="50*" />
</Grid.ColumnDefinitions>
<TextBlock Text="Foo" Grid.Column="0" />
<TextBlock Text="Some long text here which overflows" TextTrimming="CharacterEllipsis" Grid.Column="1" />
<TextBlock Text="Foo" Grid.Column="2" />
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
The reason why this is important is that I have another Grid as a sibling of the ListBox which displays the 'headers' for the columns shown in the ListBox as follows,
<Grid>
... Headers and column definitions here
</Grid>
<ListBox ...>
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
... Matching column definitions here
</Grid>
</DateTemplate>
</ListBox.ItemTemplate>
</ListBox>
and so it is important that the columns match up.
I have tried to bind the ColumnDefinitions inside the DataTemplate to the external Grid ColumnDefinitions but I cannot get easily a binding reference to it.

This is one of the most annoying problems with WPF. Since the available space yielded to the templated grid is infinite, the actual content will take as much space as it wants.
The simplest way is to fix a certain width to the Grid, but that solves only the situations where there's no resizing.
Whereas you want to stretch the ListBox size (width, in the specific), unfortunately I guess that there's no any better solution other than a custom converter.
Here is my solution:
<Window.Resources>
<local:MyConv x:Key="cv1" />
</Window.Resources>
<Grid>
<ListBox
ItemsSource="{Binding Foo, FallbackValue=1234}"
HorizontalContentAlignment="Stretch"
>
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Width="{Binding Path=ActualWidth, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListBox}, Converter={StaticResource cv1}}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50*" />
<ColumnDefinition Width="100*" />
<ColumnDefinition Width="50*" />
</Grid.ColumnDefinitions>
<TextBlock Text="Foo" Grid.Column="0" />
<TextBlock Text="Some long text here which overflows" TextTrimming="CharacterEllipsis" Grid.Column="1" />
<TextBlock Text="Foo" Grid.Column="2" />
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
And the converter:
class MyConv : IValueConverter
{
public object Convert(
object value,
Type targetType,
object parameter,
System.Globalization.CultureInfo culture
)
{
return (double)value - 30.0;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}

Even though this is an old post I'm adding my findings as they might be relevant for other people reading this post.
I had a similar issue (my * columns weren't dividing the width evenly as expected anymore, they were just sizing based on the content).
The root cause here was that I had a ListView with an ItemsSource linked to a List. The ListView in WPF contains a ScrollViewer and a ScrollViewer doesn't have a fixed width.
Without a fixed width a Grid can't properly determine what width to give to a * column and switches to a different sizing method.
Solution
I now use an ItemsControl which doesn't contain a ScrollViewer and thus the Width is known allowing the Grid to properly size it's columns.
For more details on how exactly the Grid handles it's sizing I suggest you decompile the Grid class and have a look at the following method:
protected override Size MeasureOverride(Size constraint)
This is my MainWindow.xaml from my test application (comment out the ListView to see the difference in behaviour):
<Window x:Class="WPFSO.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:wpfso="clr-namespace:WPFSO"
Title="MainWindow" Height="150" Width="525">
<Window.DataContext>
<wpfso:SharedSizeScopeViewModel />
</Window.DataContext>
<Window.Resources>
<DataTemplate DataType="{x:Type wpfso:TestViewModel}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" x:Name="SecondColumn" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" x:Name="FourthColumn" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Text="{Binding Name}" />
<TextBlock Grid.Column="1" Background="LightGray" Text="{Binding Name2}"/>
<TextBlock Grid.Column="2" Text="{Binding Name3}"/>
<TextBlock Grid.Column="3" Background="Orange" Text="{Binding Name4}"/>
<!--<TextBlock Grid.Column="1" Background="Blue" HorizontalAlignment="Stretch" />
<TextBlock Grid.Column="3" Background="Orange" HorizontalAlignment="Stretch" />-->
</Grid>
</DataTemplate>
<DataTemplate x:Key="MainDataTemplate" DataType="wpfso:SharedSizeScopeViewModel" >
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<CheckBox Grid.Row="0" Grid.ColumnSpan="4" HorizontalAlignment="Left" FlowDirection="RightToLeft" Margin="0,0,0,25">
<TextBlock FlowDirection="LeftToRight" Text="Show differences" Style="{StaticResource LabelStyle}" />
</CheckBox>
<TextBlock Grid.Row="1" Grid.Column="0" Text="PropertyName" Style="{StaticResource LabelStyle}" />
<TextBlock Grid.Row="1" Grid.Column="1" Text="Previous value" Style="{StaticResource LabelStyle}" />
<TextBlock Grid.Row="1" Grid.Column="3" Text="Current value" Style="{StaticResource LabelStyle}" />
<ListView Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="4" ItemsSource="{Binding Entries}" HorizontalAlignment="Stretch" Margin="0" HorizontalContentAlignment="Stretch"/>
</Grid>
</DataTemplate>
</Window.Resources>
<Grid Name="RootGrid">
<ItemsControl ItemsSource="{Binding Entries}" />
<!--<ListView ItemsSource="{Binding Entries}" />-->
</Grid>
</Window>
The ViewModels used during this test:
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace WPFSO
{
public class SharedSizeScopeViewModel : INotifyPropertyChanged
{
public SharedSizeScopeViewModel()
{
var testEntries = new ObservableCollection<TestViewModel>();
testEntries.Add(new TestViewModel
{
Name = "Test",
Name2 = "Looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong test",
Name3 = "Short test",
Name4 = "Nothing"
});
Entries = testEntries;
}
private ObservableCollection<TestViewModel> _entries;
public ObservableCollection<TestViewModel> Entries
{
get { return _entries; }
set
{
_entries = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}
First viewmodel
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace WPFSO
{
public class SharedSizeScopeViewModel : INotifyPropertyChanged
{
public SharedSizeScopeViewModel()
{
var testEntries = new ObservableCollection<TestViewModel>();
testEntries.Add(new TestViewModel
{
Name = "Test",
Name2 = "Looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong test",
Name3 = "Short test",
Name4 = "Nothing"
});
Entries = testEntries;
}
private ObservableCollection<TestViewModel> _entries;
public ObservableCollection<TestViewModel> Entries
{
get { return _entries; }
set
{
_entries = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}
Second viewmodel
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace WPFSO
{
public class TestViewModel : INotifyPropertyChanged
{
private string _name;
private string _name2;
private string _name3;
private string _name4;
public string Name
{
get { return _name; }
set
{
_name = value;
OnPropertyChanged();
}
}
public string Name2
{
get { return _name2; }
set
{
_name2 = value;
OnPropertyChanged();
}
}
public string Name3
{
get { return _name3; }
set
{
_name3 = value;
OnPropertyChanged();
}
}
public string Name4
{
get { return _name4; }
set
{
_name4 = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}

Set
TextTrimming="CharacterEllipsis"
on the TextBlock.
It works for me. As you have defined the middle column should be twice the size of the other.

I find myself in a similar situation but TextTrimming isn't available.
Ends up binding child Width to Grid.ActualWidth with a Converter converts the ratio into absolute width.
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50*" />
<ColumnDefinition Width="100*" />
<ColumnDefinition Width="50*" />
</Grid.ColumnDefinitions>
<Grid.Resources>
<local:PartConv x:Key="partConv"/>
<sys:Double x:Key="r0">0.25</sys:Double>
<sys:Double x:Key="r1">0.5</sys:Double>
<sys:Double x:Key="r2">0.25</sys:Double>
</Grid.Resources>
<TextBlock Text="Foo" Grid.Column="0"
Width="{Binding ActualWidth,
RelativeSource={RelativeSource AncestorType=Grid}},
Converter={StaticResource partConv},
ConverterParameter={StaticResource r0}}"/>
<TextBlock Text="Some long text here which overflows" Grid.Column="1"
Width="{Binding ActualWidth,
RelativeSource={RelativeSource AncestorType=Grid}},
Converter={StaticResource partConv},
ConverterParameter={StaticResource r1}}"/>
<TextBlock Text="Foo" Grid.Column="2"
Width="{Binding ActualWidth,
RelativeSource={RelativeSource AncestorType=Grid}},
Converter={StaticResource partConv},
ConverterParameter={StaticResource r2}}"/>
</Grid>
[ValueConversion(typeof(double), typeof(double))]
public class PartConv : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
=> ((double)value) * ((double)parameter);
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
=> ((double)value) / ((double)parameter);
}

Listbox with UserControl ItemTemplate always shows default values

To start off, I have a listbox that is trying to accept a UserControl as the DataTemplate:
<ListBox VerticalAlignment="Stretch" Name="GeneralMcmView" Grid.Column="0" HorizontalAlignment="Stretch" >
<ListBox.ItemTemplate>
<DataTemplate DataType="local:GeneralMcmMessage">
<local:GeneralMcmMessage />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
With the contents of the usercontrol looking like:
<ContentControl FontFamily="Segoe UI" VerticalAlignment="Stretch" FontSize="10">
<Grid VerticalAlignment="Stretch">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<StackPanel VerticalAlignment="Stretch" Orientation="Horizontal" Grid.Row="0">
<TextBlock Name="MessageDateTime" Text="{Binding ElementName=_this, Path=TimeStamp, StringFormat=MM/dd/yyyy h:mm:ss.fff tt \'GMT\' (zzz)}" />
<TextBlock Name="MessageTypeLabel" Margin="15,0,5,0" Text="Type:"/>
<TextBlock Name="MessageType" Text="{Binding ElementName=_this, Path=Type}" />
</StackPanel>
<StackPanel VerticalAlignment="Stretch" Orientation="Horizontal" Grid.Row="1">
<TextBlock Name="MessageNameLabel" Margin="0,0,5,0" Text="Message Name:" />
<TextBlock Name="MessageNameValue" Text="{Binding ElementName=_this, Path=MessageName}" TextWrapping="Wrap" />
</StackPanel>
<StackPanel VerticalAlignment="Stretch" Orientation="Vertical" Grid.Row="2">
<TextBlock Name="MessageLabel" Text="Message:"/>
<TextBlock Name="Message" Margin="10,0,0,0" Text="{Binding ElementName=_this, Path=MessageContent}" />
</StackPanel>
</Grid>
</ContentControl>
I then create a couple messages, all with different data (The Listbox's ItemSource is bound to the GeneralMessages ObservableCollection):
GeneralMcmMessage newMsg = new GeneralMcmMessage()
{
MessageId = e.McmMessageViewInfo.Id,
TimeStamp = e.McmMessageViewInfo.MessageDateTime,
Type = e.McmMessageViewInfo.MessageType.ToString(),
MessageName = e.McmMessageViewInfo.MessageName,
MessageContent = e.McmMessageViewInfo.Message.ToString()
};
GeneralMessages.Add( newMsg );
During runtime I interrogate the Items property of the listbox and all the data looks correct, however all I see in the listbox are entries of the GeneralMcmMessage User Control with default data values. Any ideas as to why?
Also, FWIW I am using INotifyPropertyChanged in the usercontrol class:
public partial class GeneralMcmMessage : UserControl, INotifyPropertyChanged
{
private Constants.PiuModule piuModule = Constants.PiuModule.MCM;
private string className = "GeneralMcmMessage";
/// <summary>
/// Event for notifying listeners that a property changed. Part of INotifyPropertyChanged
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
public int MessageId { get; set; }
private DateTime timeStamp;
public DateTime TimeStamp
{
get
{
return timeStamp;
}
set
{
timeStamp = value;
OnNotifyPropertyChanged( "TimeStamp" );
}
}

You're saying that the DataTemplate to display a GeneralMcmMessage is to instantiate new GeneralMcmMessage.
<DataTemplate DataType="local:GeneralMcmMessage">
<local:GeneralMcmMessage />
</DataTemplate>
I'd recommend instead of making a collection of your UserControl to make a collection of your model object instead, and bind to the properties within that within your UserControl.
Either way though - the object you created in code will be the DataContext for the one you created in XAML so removing the ElementName=_this should bind appropriately. Try this simplified XAML in your UserControl instead.
<StackPanel VerticalAlignment="Stretch" Orientation="Horizontal" Grid.Row="0">
<TextBlock Name="MessageDateTime" Text="{Binding TimeStamp, StringFormat=MM/dd/yyyy h:mm:ss.fff tt \'GMT\' (zzz)}" />
<TextBlock Name="MessageTypeLabel" Margin="15,0,5,0" Text="Type:"/>
<TextBlock Name="MessageType" Text="{Binding Type}" />
</StackPanel>
<StackPanel VerticalAlignment="Stretch" Orientation="Horizontal" Grid.Row="1">
<TextBlock Name="MessageNameLabel" Margin="0,0,5,0" Text="Message Name:" />
<TextBlock Name="MessageNameValue" Text="{Binding MessageName}" TextWrapping="Wrap" />
</StackPanel>
<StackPanel VerticalAlignment="Stretch" Orientation="Vertical" Grid.Row="2">
<TextBlock Name="MessageLabel" Text="Message:"/>
<TextBlock Name="Message" Margin="10,0,0,0" Text="{Binding MessageContent}" />
</StackPanel>

You don’t post all code of GeneralMcmMessage hence I don’t know if you set DataContext in user control for example in constructor of GeneralMcmMessage.
I tried replicate your problem.
User control GeneralMcmMessage code behind
public partial class GeneralMcmMessage : UserControl, INotifyPropertyChanged
{
private int _messageId;
public int MessageId
{
get
{
return _messageId;
}
set
{
_messageId = value;
OnPropertyChanged("MessageId");
}
}
private DateTime _timeStamp;
public DateTime TimeStamp
{
get
{
return _timeStamp;
}
set
{
_timeStamp = value;
OnPropertyChanged("TimeStamp");
}
}
public GeneralMcmMessage()
{
InitializeComponent();
//don’t set data context here
//DataContext = this;
}
}
User control GeneralMcmMessage XAML
<StackPanel>
<TextBlock Margin="5" FontSize="20" Text="{Binding Path=MessageId}"/>
<TextBlock Margin="5" FontSize="20" Text="{Binding Path=TimeStamp}"/>
</StackPanel>
User control GeneralMcmMessage usage
public partial class MainWindow : Window, INotifyPropertyChanged
{
private ObservableCollection<GeneralMcmMessage> _generalMessages;
public MainWindow()
{
InitializeComponent();
DataContext = this;
}
public ObservableCollection<GeneralMcmMessage> GeneralMcmMessages
{
get { return _generalMessages; }
set
{
_generalMessages = value;
OnPropertyChanged("GeneralMcmMessages");
}
}
private void MainWindow_OnLoaded(object sender, RoutedEventArgs e)
{
GeneralMcmMessages = new ObservableCollection<GeneralMcmMessage>();
for (int i = 0; i < 10; i++)
{
var newMsg = new GeneralMcmMessage
{
MessageId = i,
TimeStamp = DateTime.Now,
};
GeneralMcmMessages.Add(newMsg);
}
}
}
User control GeneralMcmMessage usage XAML
<ListBox x:Name="ListBox"
Margin="5"
ItemsSource="{Binding Path=GeneralMcmMessages}">
<ListBox.ItemTemplate>
<DataTemplate DataType="stackoverflow:GeneralMcmMessage">
<stackoverflow:GeneralMcmMessage/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
If this not solve your problem could you please post all GeneralMcmMessage?
If you want I can upload sample project for you.
Thank you

How to bind form Code activity to XAML?

I'm trying to make an activity designer library. I have two sources; one of them is CodeActivity in C# code and the other one is Activity designer in XAML. In CodeActivity, I have a public property Name. In XAML, I want to view and change it's value through binding. My XAML design is like this
I declared Name property like this:
private string _name;
public string Name {
get { return _name; }
set
{
_name = value;
NotifyPropertyChanged("Name");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,
new PropertyChangedEventArgs(propertyName));
}
}
And my XAML is like this:
...
<DataTemplate x:Key="Expanded">
<StackPanel>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="25"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="40"/>
<ColumnDefinition Width="130"/>
</Grid.ColumnDefinitions>
<TextBox x:Name="txtName" Grid.Column="1" Grid.Row="0" Text="{Binding Name, Mode=TwoWay}"/>
<TextBlock Grid.Column="0" Grid.Row="0" Text="Name :" HorizontalAlignment="Right"/>
</Grid>
<sap:WorkflowItemPresenter Item="{Binding Path=ModelItem.Body, Mode=TwoWay}"
HintText="Please drop an activity here" />
</StackPanel>
</DataTemplate>
I've tried a lot of ways, but I couldn't do it.
How can I show the Name property from CodeActivity in XAML?

I got it.
When we want to bind a variable from CodeActivity Side to XAML, we do like this :
...
xmlns:s="clr-namespace:System;assembly=mscorlib"
<sap:ActivityDesigner.Resources>
<sapc:ArgumentToExpressionConverter x:Key="ArgumentToExpressionConverter" />
...
<sapv:ExpressionTextBox HintText="Enter custom text here ..." Expression="{Binding Path=ModelItem.Text, Mode=TwoWay, Converter={StaticResource ArgumentToExpressionConverter}, ConverterParameter=In}" ExpressionType="s:String" OwnerActivity="{Binding Path=ModelItem}" MaxLines="1"/>
...

WPF Listview + GridView - View not Updating

I have got a Listview Item with a Gridview Child, bound to a List of Objects.
Below the Gridview I have got texboxes to edit the content of the Gridview (bound to the Gridview).
I can add new content (which is displayed in the GridView).
When i edit content, it is in fact edited (in the object list) but not displayed in the Gridview (the GridView does not seem to update)
xaml code:
<!-- ========= -->
<!-- root Grid -->
<!-- ========= -->
<Grid x:Name="root" Margin="10,10,10,10">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="25" />
<RowDefinition Height="25" />
<RowDefinition Height="40" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="40" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<!-- ========= -->
<!-- Data Grid -->
<!-- ========= -->
<ListView x:Name="dataGrid" Grid.Row="0" Grid.ColumnSpan="2" ItemsSource="{Binding}">
<ListView.View>
<GridView>
<!-- first solution -->
<GridViewColumn x:Name="gridColumnName" Header="Name" Width="160">
<GridViewColumn.CellTemplate>
<DataTemplate>
<ContentControl Content="{Binding Path=Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
<!-- second solution -->
<GridViewColumn x:Name="gridColumnPath" Header="Path" DisplayMemberBinding="{Binding Path=Path}" Width="490" />
</GridView>
</ListView.View>
</ListView>
<!-- ========= -->
<!-- Edit Menu -->
<!-- ========= -->
<Label Content="Name:" Grid.Row="1" Grid.Column="0" VerticalAlignment="Bottom" HorizontalAlignment="Left"/>
<TextBox x:Name="txtBoxName" Grid.Row="1" Grid.Column="1" Width="250" VerticalAlignment="Bottom" HorizontalAlignment="Left"
DataContext="{Binding ElementName=dataGrid, Path=SelectedItem}"
Text="{Binding Path=Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
<Label Content="Path:" Grid.Row="2" Grid.Column="0" VerticalAlignment="Bottom" HorizontalAlignment="Left" />
<TextBox x:Name="txtBoxPath" Grid.Row="2" Grid.Column="1" VerticalAlignment="Bottom" HorizontalAlignment="Stretch"
DataContext="{Binding ElementName=dataGrid, Path=SelectedItem}"
Text="{Binding Path=Path, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
Object List class:
class ItemList : ObservableCollection<LdapItem>
{
public ItemList()
: base()
{
}
}
Object class:
class LdapItem : INotifyPropertyChanged
{
#region constructor
public LdapItem(String name, String path)
{
this.iD = Guid.NewGuid().ToString();
this.name = name;
this.path = path;
}
#endregion
#region public proterties
public String ID
{
get { return iD; }
}
public String Name
{
get { return name; }
set { name = value; }
}
public String Path
{
get { return path; }
set { path = value; }
}
#endregion
#region public methods
public void OnPropertyChanged(string prop)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(prop));
}
#endregion
#region private variables
private String name = String.Empty;
private String path = String.Empty;
private String iD = String.Empty;
#endregion
public event PropertyChangedEventHandler PropertyChanged;
}
any ideas why updating the GridView doesnt work?

If you have a number of models use a base class that implements INPC. Then change your property changed event handler to:
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
This will eliminate the need to specify the model property being changed. Reduces the number of misspelling errors or forgetting to put the name in. Still needs to call this.OnPropertyChanged() though which you are missing in several setters.
The ItemList class doesn't make sense. It could be replaced with:
public ObservableCollection<LdapItem> LdapItems

it seems like you forgot to fire the OnPropertyChangedEvent when your property changes:
public String Name
{
get { return name; }
set {
name = value;
OnPropertyChanged("Name");
}
}
If you don't fire the PropertyChanged event, WPF will not be able to see if the object has changed.