Develop Reference

WPF - TextBox not binding properly when set to readonly

I have TextBox that I'm using to add (only to add and not read) file path into DB. Text property is set when user selects certain file (OpenFileDialog). So, I set it in readonly state and it won't bind properly. When I remove readonly it works fine.
<Button Name="btnAddFile" Content="+" HorizontalAlignment="Left" Width="23" Height="23" Click="AddFilePath"/>
<TextBox Name="tbxFilePath" Height="23" Text="{Binding FilePath}" Width="364" IsReadOnly="True"/>
When I use:
Text="{Binding FilePath, Mode=OneWayToSource}"
it sometimes work but most of the time it doesn't (?!). I could use TextBlock or Label but I would really like to understand what is going on and use TextBox.
I'm using Entity Framework but don't think it does matter.
Question: How can I programmatically add text to TextBox control which is readonly and be able to bind it.
EDIT: I figured out what the problem is. When I set focus on TextBox after I set it's Text property from code-behind, it works. I guess it has to notify that Text is changed when I do it from code-behind. How to do that?

Have you tried using OneWay Binding?
MSDN reads:
OneWay Updates the binding target (target) property when the binding source (source) changes. This type of binding is appropriate if the control being bound is implicitly read-only.
Which I think covers your scenario.
The target is your TextBox Text property and your source is your FilePath property on your ViewModel.
Use:
Text="{Binding FilePath, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"
EDIT
This answer assumes you have implemented INotifyPropertyChanged on your ViewModel.
EDIT
The correct binding mode is OneWayToSource. Confirmed by OP.

How to control when TextBox Text as binding source updates the target value?

Trying for a simple thing. I want TextBlock text to be updated to what TextBox's text value is. However, I want it to happen only on LostFocus. Currently below code updates a TextBlock as user is typing into a TextBox. How do we achieve that?
<StackPanel>
<TextBox x:Name="txtQty" />
<TextBlock Text="{Binding ElementName=txtQty, Path=Text}" />
</StackPanel>
I explored the UpdateSourceTrigger property on textbox with LostFocus, but it won't work as that controls how the source should be updated, whereas here I need how the destination updates.
I prefer to have a XAML only solution.

XAML is a markup language.
The straight-forward way to to this would be to bind the TextBox and the TextBlock to the same view model source property. The source property will be set when the TextBox loses focus and then the TextBlock will then be updated provided that the view model class implements the INotifyPropertyChanged interface as expected.
You could of course also handle the LostKeyboardFocus event for the TextBox and set the Text property of the TextBlock programmatically in the code-behind of the view. This approach is not any worse than trying to implement some logic in the XAML markup of the very same view. Just because you possibly can do something in pure XAML, it doesn't mean that you always should. A programming language such as C# usually does a better job implementing some logic.

As others already said, the best way would be to bind the TextBlock and the TextBox to the same viewmodel property.
If you want to do it only with XAML code you could try it from the other side and bind your TextBox to the TextBlock.
Like this:
<StackPanel>
<TextBox Text="{Binding ElementName=txtQty, Path=Text, UpdateSourceTrigger=LostFocus, Mode=OneWayToSource}" />
<TextBlock x:Name="txtQty" />
</StackPanel>

Force Refreshing WPF Bindings (one source)

I have this situation:
A IsToolbarButtonsEnabledProperty DependencyProperties
A have plenty of other DependencyProperties in a class (a huge class, needs to be this way)
A serie of Buttons on a toolbar.
The (IsEnabled) property of each of these buttons is a function of (IsToolbarButtonsEnabledProperty) throught a special converter, the buttons a differenced by ConvertParameter ("PreviousButton", "NextButton"...)
Opacity="{Binding IsEnabled, RelativeSource={RelativeSource Self}, Converter={StaticResource OpacityBoolToIntConverter}, UpdateSourceTrigger=PropertyChanged}"
IsEnabled="{Binding Path=DPEnableLinks, Converter={StaticResource ToolButtonEnableConverter}, ConverterParameter='ZoomOut' }"
ToolButtonEnableConverter is a converter that compares ConverterParameter "PreviousButton" with other value of other dependency property (in class). I have to many DP to make one multivalueconverter, so I read them straight from my class ((MainWindow)App.Current.MainWindow;)
Questions
When I update other DPs the value isEnabled / Opacity, dont change. How to fix this?
Is there a general solution to make a Binding refresh everytime a DP changes.
(Repeating myself): I will be adding more and more DPs over time, so a MultiValueConverter seams odd.

One way to force the Binding to update is to create a (meaningless) property and add it to the Binding (using MultiBinding), and when you want to update your Binding you change that property, and all the Binding is updated.
I must add that the more "straightforward" way is to use MultiBinding to all the relevant properties. If you have way to many properties that you need to bind, maybe you should re-think if you can build this functionality some other way.

WPF Activate binding OnTextInput on textbox

I have a textbox with the following binding :
<TextBox Binding={Path=MyStr, Mode=TwoWay}>
My problem is that the binding only fires when the textbox loses focus and not for each char the user enters.
The textbox also has an OnTextInput function that fires properly but how do I activate the binding in the code behind?
*I'd rather doing it in a pure mvvm way (not use the window's code behind if possible)
Any answer will be accepted mvvm or not.

Here:
<TextBox Text="{Binding Path=MyStr, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
now your bound property will be changed on each character.

U can use the updatesource trigger and set it to property changed
<Binding Source="{StaticResource myDataSource}" Path="Name"
UpdateSourceTrigger="PropertyChanged"/>
The moment it is changed it will sent it's updated value back to your DataContext
on msdn:
http://msdn.microsoft.com/en-us/library/system.windows.data.updatesourcetrigger.aspx

There is a UpdateSourceTrigger Called PropertyChanged, if you use that as your update trigger when you change the text of the textbox it will fire and in your binding property setter you can perform what ever action you need to happen as text changes.
<TextBox Text="{Binding Path=Text,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />

Binding in DynamicResource ResourceKey wpf mvvm

I want to bind the style of button on the basis of if else condition. I have created one string property in the viewmodel and bind to the button's style attribute like this:
<Button x:Name="copd" Content="COPD"
Command="{Binding COPDReadingsCommand}"
Style="{DynamicResource ResourceKey={Binding CheckCopd}}"
HorizontalAlignment="Center" VerticalAlignment="Center"
Margin="20" FontWeight="Bold" />
I am looping through the resourceDictionary and getting all the keys. Using if else i am changing the string property value(CheckCopd) in if else.
I am getting the desired values in if else but style is not getting applied to the button when I execute my application. It only displays the generic button style.
How to bind the DynamicResource ?
Kindly Suggest?
Thank You.

You cannot use bindings on the DynamicResource properties, as it does not derive from DependencyObject. You would either need to set the Style property directly from code-behind, or just use a Binding.
You could use a Style for the Button type, which has a DataTrigger based on a custom property that dynamically changes the look. But in this case, you need a single Style, which changes it's setters based on your condition. It would not allow you to change the Style property itself dynamically.

You can try this... I came up with a way to create a DynamicResourceBinding on which you can use a converter to achieve the results you want. (You theoretically could also just use styles and triggers, but I digress...)
How do you create a DynamicResourceBinding that supports Converters, StringFormat?