WPF -- Anyone know why I can't get this binding to reference?

Question

<StackPanel x:Name="stkWaitingPatients" Width="300" Margin="0,0,0,-3"
   DataContext="{Binding Mode=OneWay, Source={StaticResource local:oPatients}}">

I'm getting StaticResource reference 'local:oPatients' was not found.

Here is the codebehind:

    public partial class MainWindow : Window
{
    ListBox _activeListBox;
    clsPatients oPatients;

 public MainWindow()
 {
        oPatients = new clsPatients(true);

...

Answer 1

To be able to address the object as a StaticResource, it needs to be in a resource dictionary. However, since you're creating the object in MainWindow's constructor, you can set the DataContext in the code-behind like so.

oPatients = new clsPatients(true);
stkWaitingPatients.DataContext = oPatients;

And then change the Binding to this:

{Binding Mode=OneWay}

This is an ok practice if you're not going to be changing the DataContext again, otherwise you'd want a more flexible solution.

Edit: You mentioned ObjectDataProvider in your comment. Here's how you'd do that. First, add an xmlns:sys to the Window for the System namespace (I'm assuming you already have one for xmlns:local):

xmlns:sys="clr-namespace:System;assembly=mscorlib"

Then you can add an ObjectDataProvider to your resource dictionary like this:

<Window.Resources>
    <ObjectDataProvider
        x:Key="bindingPatients"
        ObjectType="{x:Type local:clsPatients}">
        <ObjectDataProvider.ConstructorParameters>
            <sys:Boolean>True</sys:Boolean>
        </ObjectDataProvider.ConstructorParameters>
    </ObjectDataProvider>
</Window.Resources>

And refer to it in a Binding with the StaticResource markup like this, using the same string we specified in the x:Key attached property we gave it in the dictionary:

{Binding Source={StaticResouce bindingPatients}, Mode=OneWay}

Edit 2: Ok, you posted more code in your answer, and now I know why it's throwing an exception during the constructor. You're attempting to do this...

lstWaitingPatients.DataContext = oPatients;

... but lstWaitingPatients doesn't actually exist until after this.InitializeComponent() finishes. InitializeComponent() loads the XAML and does a bunch of other things. Unless you really need to do something before all of that, put custom startup code after the call to InitalizeComponent() or in an event handler for Window's Loaded event.

Answer 2

Now, I can't get this to work...I get a general Windows startup error.

Here is the codebehind with the Initializer and the class being instantiated:

    public partial class MainWindow : Window
{
    ListBox _activeListBox;

 public MainWindow()
 {
        clsPatients oPatients = new clsPatients(true);
        lstWaitingPatients.DataContext = oPatients;

  this.InitializeComponent();

Here's the top of my XAML:

<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Orista_Charting"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" 
xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero"
x:Class="Orista_Charting.MainWindow"
x:Name="windowMain"
Title="Orista Chart"
Width="1024" Height="768" Topmost="True" WindowStartupLocation="CenterScreen" Activated="MainWindow_Activated" >


<Window.Resources>        

    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Resources/ButtonStyles.xaml"/>
            <ResourceDictionary Source="Resources/OtherResources.xaml"/>
            <ResourceDictionary Source="Resources/TextBlockStyles.xaml"/>
            <ResourceDictionary Source="Resources/Converters.xaml"/>
        </ResourceDictionary.MergedDictionaries>

Here's the pertinent XAML, as you see, I went ahead and moved the DataContext down to the ListBox from the StackPanel. This doesn't run, but it does render in Design View (however, with no data present in the ListBox):

<!-- Waiting Patients List -->
   <Border BorderThickness="1,1,1,1" BorderBrush="#FF000000" Padding="10,10,10,10" 
            CornerRadius="10,10,10,10" Background="#FFFFFFFF" Margin="15.245,187.043,0,41.957" HorizontalAlignment="Left" >
        <StackPanel x:Name="stkWaitingPatients" Width="300" Margin="0,0,0,-3"> 

            <StackPanel Orientation="Horizontal">    
          <TextBlock Text="Waiting Patients:" VerticalAlignment="Center" FontSize="21.333" Margin="0,0,0,20"/>
          <TextBlock HorizontalAlignment="Right" Margin="0,0,38.245,0" Width="139" Height="16" 
    Text="Minutes Waiting" TextWrapping="Wrap" Foreground="#FF9C2525" FontWeight="Bold" VerticalAlignment="Bottom"
    TextAlignment="Right"/> 
                <!-- Too be implemented, this is the wait animation -->
                <!--<Image x:Name="PollGif" Visibility="{Binding Loading}"
                       HorizontalAlignment="Left" Margin="100,0,0,0" Width="42.5" Height="42.5" 
                       Source="Images/loading-gif-animation.gif" Stretch="Fill"/>-->       
         </StackPanel>                  

            <ListBox x:Name="lstWaitingPatients"       
                     DataContext="{Binding Mode=OneWay}" ItemsSource="{Binding Mode=OneWay}"
                     IsSynchronizedWithCurrentItem="true"
                     ItemTemplate="{StaticResource WaitingPatientsItemTemplate}"
                     FontSize="21.333" Height="423.291" ScrollViewer.VerticalScrollBarVisibility="Visible"
                     GotFocus="lstWaitingPatients_GotFocus"
                     />

        </StackPanel>
    </Border>

Ok, but if I just take comment out the assigment line in the codebehind, it does run (albeit with no data in the listbox):

    public partial class MainWindow : Window
{
    ListBox _activeListBox;

 public MainWindow()
 {
        clsPatients oPatients = new clsPatients(true);
        //lstWaitingPatients.DataContext = oPatients;

THANKS!

Answer 3

The following sets the ItemsSource in Code Behind and correctly handles the DataBinding:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        clsPatients oPatients = new clsPatients(true);

        //assuming oPatients implements IEnumerable
        this.lstWaitingPatients.ItemsSource = oPatients;

And the XAML:

<ListBox x:Name="lstWaitingPatients"       
         IsSynchronizedWithCurrentItem="true"
         ItemTemplate="{StaticResource WaitingPatientsItemTemplate}"
         FontSize="21.333" Height="423.291"
         ScrollViewer.VerticalScrollBarVisibility="Visible"
         GotFocus="lstWaitingPatients_GotFocus"
         />