WPF user control's datacontext to property in codebehind

Question

Having a simple XAML user control, I'd like to set the DataContext to the code behind (xaml.cs) file.

I'd like to set DataContext and Itemssource in XAML, so I can populate the combobox with property ListOfCars

XAML

<UserControl x:Class="Sample.Controls.MyControl"
             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" 
             d:DesignHeight="85" d:DesignWidth="200">
    <Grid Height="85" Width="200" Background="{StaticResource MainContentBackgroundBrush}">
        <StackPanel Orientation="Vertical">                
            <ComboBox Height="23.338" x:Name="CarList" />                
        </StackPanel>    
    </Grid>
</UserControl>

Code behind

public List<Cars> ListOfCars
{
  get { return _store.ListCars(); }
}

In other words, instead of doing this in codebehind, how may I set the binding in XAML

public MyControl()
{
  InitializeComponent();
  _store = new Store();
  CarList.ItemsSource = _store.ListCars();
  CarList.DisplayMemberPath = "Name";
}

N_A · Accepted Answer · 2012-09-07 13:58:46Z

1

Just bind the ItemsSource.

<ComboBox ItemsSource="{Binding ListOfCars}"/>

And then for the UserControl:

<MyControl DataContext="{Binding *viewModel*}"/>

You have to bind the DataContext where your UserControl is used rather than in the definition, because in the definition you don't know to what to bind. The Combobox automatically is in the context of the control so you can just bind to the DataContext without any additional work.

Example of binding to a resource:

<Application.Resources>
  ...
  <viewmodels:ViewModelLocator x:Key="ViewModelLocator"/>
  ...
</Application.Resources>


<MyControl DataContext="{Binding Source={StaticResource ViewModelLocator}}"/>

This creates an instance of the ViewModelLocator and then binds the DataContext of the control to that resource.

edited Sep 7, 2012 at 13:58

answered Sep 7, 2012 at 13:36

N_A

20k4 gold badges55 silver badges98 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Kman Over a year ago

Don't quite get the {Binding viewModel}. It's not working, but how may viewModel be binded to the code behind, without hooking it up in someway. Don't have a specific viewmodel for this xaml

N_A Over a year ago

You have to define your view model somewhere. This can be the DataContext in which you use your control (then bind like this {Binding}) or it can be a static resource (then bind like this {Binding Source={StaticResource *resource name*}}, but you have to define what you're binding to somewhere.

N_A Over a year ago

Read through this for some basics on binding to a view model: msdn.microsoft.com/en-us/library/hh821028.aspx

Kman Over a year ago

Thanks, .. I understand that I should read up on this as my binding knowledge is very limited at the moment :)

Kman Over a year ago

But I'm really not using the MVVM pattern for this, .. or at least not to my understanding. Just like to do the binding in xaml instead of in code behind (see question update)

|

Community · Accepted Answer · 2017-05-23 12:31:24Z

1

Do not do that, you will mess up all external bindings to the DataContext. Use UserControl.Name and ElementName bindings instead (or RelativeSource).

edited May 23, 2017 at 12:31

CommunityBot

11 silver badge

answered Sep 7, 2012 at 13:39

brunnerh

188k30 gold badges362 silver badges434 bronze badges

1 Comment

N_A Over a year ago

I don't think that's what he was intending to do. It seems more like he was just confused about how to set the binding.

Collectives™ on Stack Overflow

WPF user control's datacontext to property in codebehind

2 Answers 2

7 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

7 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related