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How to bind string property to TextBox within ListBox

I'm binding a List<string> to my ListBox in WPF using MVVM
At the moment I have
<ListBox ItemsSource="{Binding FileContents}"></ListBox>
File Contents in my ViewModel is simply
public List<string> FileContents {get;set;}
And the FileContents values are set in the constructor of the ViewModel, as such there is no need to worry about INotifyProperty
Everything works fine so far. I can see the list displayed in my ListBox as desired.
Now I need to provide a template! This is where it goes wrong
<ListBox ItemsSource="{Binding FileContents}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBox Text="{Binding}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
This is where it all goes wrong! My understanding is that I only need to do <TextBox Text = "{Binding}" because the ListBox is already bound to the List<string> property (called FileContents)
However, when I run the above Visual Studio gives me
The application is in break mode
If I update the code to
<TextBox Text = "Some String Value"
then it works fine
I don't understand what I've done wrong.

Set the Mode of the Binding to OneWay:
<TextBox Text="{Binding Path=., Mode=OneWay}" />
The default binding mode for the Text property of a TextBox is TwoWay but this won't work when you bind to a string in a List<string>.

Binding to a string directly is only possible one way. This means you are only able to bind read only like
<TextBox Text="{Binding Mode=OneWay}"/>
or
<TextBox Text="{Binding .}"/>
The reason is simple: Changing the string means you are removing and adding an item to your list. This is simply not possible by changing the string in a TextBox.
A solution is to wrap the content in a class like
public class FileContent
{
public string Content { get; set; }
}
and bind to a list of List<FileContent> by using <TextBox Text="{Binding Content}"/> as template.

Binding Property of an Item in an ItemsControl From a Collection

My theory code:
ScriptContainerUserControl.xaml
<ItemsControl x:Name="ScriptItemsControl">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<TextBox x:Name="pTB" Text="{Binding PhasePriority}" />
<TextBox x:Name="nTB" Text="{Binding Name}" />
<TextBox x:Name="dTB" Text="{Binding Description}" />
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
ScriptContainerUserControl.xaml.cs
public ScriptContainerUserControl() : base()
{
InitializeComponent();
ScriptItemsControl.ItemsSource = PScriptCollection;
}
//PScriptCollecion is of type SynchronizedObservableCollection<ProcessScript>
//ProcessScript has the elements PhasePriority, Name, and Description
Would the code above work for making sure
ScriptItemsControl[i].dTB.Text = PScriptCollection[i].Description?
Or is it not possible to bind like this?

Fenster,
It should definitely work, provided you have getter setter properties implemented for all the three properties in ProcessScript class.
When you use a datatemplate - it means you are setting the datacontext of each element of your itemscontrol to an element of your collection.
so here each Itemcontrol element will look at ProcessScript object and if that object has all three properties , you should see the data.

It is not possible to do it in this way. You do not set Binding actually... To have support for observing a changes on collection you should bind the collection to ItemsSource property of ItemsControl.
Instead of line:
ScriptItemsControl.ItemsSource = PScriptCollection;
try this
ScriptItemsControl.ItemsSource = new Binding("PScriptCollection");

How to get textblock binding value?

I had bind my textblock in xaml, is it possible to get the value out into my coding?
My coding for binding
<TextBlock Height="40" HorizontalAlignment="Left" Margin="8,24,10,0" Name="txtBlockCustName" Text="{Binding CustName, Mode=OneWay}" VerticalAlignment="Top" FontSize="26" />
I want to put in my mainpage.xaml.cs like
string CustName = txtBlockCustName.Text;
but it had error on it..

You can't access this textblock because it is bound in a listboxtemplate. If there are multiple textblocks in the list, how can you access it by name? The program won't know what textblock you are asking for. This is why an error is thrown.
You could use the collection that you bound to the listbox to get the customer name.

Windows Phone 7.1: How to add & delete items from LongListSelector control?

Windows Phone 7.1: How to add/delete items from LongListSelector control?
I am using a LongListSelector control from 'Windows Phone Toolkit'. The control is data bound to a ViewModel inherited from an ObservableCollection. When I try the following code:
MyObject mo = new MyObject("Name", "Description", "Value");
App.MyObjectsViewModel.Add(mo);
The ViewModel does seem to get updated but the LongListSelector does not update? What am I missing?
PS: I am new to Silverlight and WP7 development.
Following the XAML for the LongListSelector and the DataTemplates. The code is pretty much straight out of the Windows Phone Toolkit sample (removed some formatting related code to keep the post small)
<DataTemplate x:Key="groupHeader">
<TextBlock Text="{Binding Key}"/>
</DataTemplate>
<DataTemplate x:Key="groupItemHeader">
<Border>
<TextBlock Text="{Binding Key}"
Foreground="#FFFFFF"
FontSize="{StaticResource PhoneFontSizeLarge}"/>
</Border>
</DataTemplate>
<DataTemplate x:Key="myobjectItemTemplate">
<Grid>
<StackPanel VerticalAlignment="Top" Orientation="Vertical">
<TextBlock Text="{Binding Symbol}"/>
<TextBlock Text="{Binding Value}"/>
<TextBlock Text="{Binding Description}" TextWrapping="Wrap"/>
</StackPanel>
</Grid>
</DataTemplate>
<controls:PivotItem Header="myobjects">
<toolkit:LongListSelector x:Name="myobjectsList"
Background="Transparent"
GroupHeaderTemplate="{StaticResource groupHeader}"
GroupItemTemplate="{StaticResource groupItemHeader}"
ItemTemplate="{StaticResource myobjectItemTemplate}"
GroupViewOpened="LongListSelector_GroupViewOpened"
GroupViewClosing="LongListSelector_GroupViewClosing"/>
</controls:PivotItem>
C# code behind for setting the ItemSource
var myobjectsByClassification = from myobjects in App.MyObjectsLibrary
group myobjects by myobjects.Classification into c
orderby c.Key
select new PublicGrouping<string, MyObject>(c);
this.myobjectsList.ItemsSource = myobjectsByClassification;

My guess is that the grouping code is only being called once somewhere in code behind. So the grouped collection is not updated when you add something to your ViewModel collection. The easiest way to handle this (but maybe not the most elegant) is to create your own AddItem() method for the ViewModel collection.
class MyViewModelObject
{
void AddItem( MyObject obj )
{
App.MyObjectsLibrary.Add( obj );
MyObjectsByClassification = from myobjects in App.MyObjectsLibrary
group myobjects by myobjects.Classification into c
orderby c.Key
select new PublicGrouping<string, MyObject>(c);
}
}
Bind MyObjectsByClassification to LongListSelector.ItemsSource in XAML, and make sure you notify the LongListSelector of changes to the property by using INotifyPropertyChanged.

By using LINQ, the object you actually assign to ItemsSource is an IEnumerable<T> not an ObservableCollection<T>. LINQ-to-objects does not support automatic updating via ObservableCollection. After all, it returns a forward-only IEnumerable<T> and not a collection of any kind.
Change your ViewModel to actually expose an ObservableCollection<PublicGrouping<string, MyObject>> and bind your ItemsSource directly to that.

Why can't I Bind a viewmodel property to a dependency property of a custom control

I want to use a color picker in my wpf application and I saw a nice looking one on this codeproject page. The control works fine until I want to connect the control to a viewmodel.
I created a small test program with this viewmodel:
public class ColorViewModel : ViewModelBase
{
public ColorViewModel()
{
LineColor = Brushes.Yellow;
}
SolidColorBrush _brushColor;
public SolidColorBrush LineColor
{
get { return _brushColor; }
set
{
_brushColor = value;
RaisePropertyChanged(() => LineColor);
}
}
}
The test program has a textbox and the colorpicker controls:
<StackPanel Orientation="Horizontal">
<TextBlock Text="Please Select a Color" FontWeight="Bold" Margin="10"
Foreground="{Binding Path=LineColor, UpdateSourceTrigger=PropertyChanged}"/>
<vw:ColorPickerControlView x:Name="ForeColorPicker" Margin="10"
CurrentColor="{Binding Path=LineColor, UpdateSourceTrigger=PropertyChanged }"/>
</StackPanel>
In the loaded event of the main window in my test application I set the viewmodel to the datacontext like this:
DataContext = new ColorViewModel();
The problem is that I can't seem to bind the LineColor property of the viewmodel to the CurrentColor property of the ColorPickerControlView. The CurrentControl property of the ColorPickerControlView seems to be fine. The constructor looks like this:
public ColorPickerControlView()
{
this.DataContext = this;
InitializeComponent();
CommandBindings.Add(new CommandBinding(SelectColorCommand, SelectColorCommandExecute));
}
In the constructor of the UserControl there is the line this.DataContext = this; I read that is is necessary to bind the dependency properties. Do I override this line when I set my viewmodel to the datacontext and is that why I can't bind to the CurrentColor property? Is there any workaround? Or did I make another mistake?

You are right in thinking that the DataContext=this phrase in the UserControl's constructor preempts if from binding to an external viewmodel. It was disccussed in this question. This is easily remedied however. There is only one DependencyProperty in the UserControl's code behind that the xaml binds to: CurrentColor.
Do this:
Add a Name="Root" attribute to the UserControl tag of the
UserControl's xaml
Change the attribute (of the Border tag)
Background="{Binding
Path=CurrentColor}" to:
Background="{Binding
ElementName=Root,
Path=CurrentColor}"
Remove the offending DataContext=this
line from the UserControl's
constructor!
That should be all that there is to it. I wrote a proof of concept that demonstrates the above. If you like I can post it, but the code above should be all you need.

Both binding must be clashing the set the value of the property. Try Setting the Mode=OneWay
<StackPanel Orientation="Horizontal">
<TextBlock Text="Please Select a Color" FontWeight="Bold" Margin="10"
Foreground="{Binding Path=LineColor, UpdateSourceTrigger=PropertyChanged, Mode=OneWay}"/>
<vw:ColorPickerControlView x:Name="ForeColorPicker" Margin="10"
CurrentColor="{Binding Path=LineColor, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay }"/>
</StackPanel>

The line this.DataContext = this isn't really needed since you are replacing the DataContext with an instance of the ViewModel. You also do not need to assign the DataContext on the Loaded event handler. Just set it on the constructor. You can set it after the call to InitializeComponent method.

Remove the line DataContext = this in file ColorPickerControlView.xaml.cs
Change the Binding in ColorPickerControlView.xaml to Background="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type CustomWPFColorPicker:ColorPickerControlView}},
Path=CurrentColor}"