ItemsSource on wpf ComboBox getting reset? - wpf

Question

I have a ComboBox setup in xaml and have set the ItemsSource binding. When I run the project nothing shows up in the ComboBox. If I inspect it with snoop the ItemsSource of the ComboBox is blank.
Anyone come across this before?
I checked the binding errors this is the error it displays
System.Windows.Data Error: 39 : BindingExpression path error: 'WasteTypeData' property not found on 'object' ''JobItems' (HashCode=28494546)'. BindingExpression:Path=WasteTypeData; DataItem='JobItems' (HashCode=28494546); target element is 'ComboBox' (Name='CboWasteTypes'); target property is 'ItemsSource' (type 'IEnumerable')
WasteTypeData is a public property of ObservableCollection<WasteTypes>.
This is what I have set as the binding of the ComboBox and if I debug the app WasteTypeData is populated with the list of WasteTypes as expected.
I can't figure out why it's looking for WasteTypeData on object JobItems. The WasteTypeData property is not found on the object JobItems.
JobItemsData is a public property of ObservableCollection<JobItems>.
My xaml has a ListBox with its ItemsSource Binding set to JobItemsData.
The ListBox has a DataTemplate with a couple of TextBoxes and one ComboBox. All the TextBoxes display their data properly.
Here's xaml if it will help shed any light on what's going on:
<UserControl
x:Class="WorkItems.View.ViewJobItems"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:JobItemsViewModel="clr-namespace:WorkItems.ViewModel"
Height="300" Width="500">
<ListBox
x:Name="LstJobItems"
ItemsSource="{Binding JobItemsData}"
VerticalAlignment="Stretch"
HorizontalAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<StackPanel
Grid.Column="0"
Margin="5">
<StackPanel
Orientation="Horizontal"
Margin="0,5,0,0">
<Label
Content="Customer Details"
FontWeight="Bold"
FontSize="24"></Label>
</StackPanel>
<StackPanel
Orientation="Horizontal">
<Line
StrokeThickness="3"></Line>
</StackPanel>
<StackPanel
Orientation="Horizontal"
Margin="0,5,0,0">
<Label
Content="Customer: "
FontWeight="Bold"
Width="110" />
<TextBox
Text="{Binding Customer, Mode=OneWay}"
Width="200" />
</StackPanel>
<StackPanel
Orientation="Horizontal"
Margin="0,5,0,0">
<Label
Content="Address: "
FontWeight="Bold"
Width="110" />
<TextBox
Text="{Binding Address1, Mode=OneWay}"
Width="200" />
</StackPanel>
<StackPanel
Grid.Column="1"
Margin="5">
<StackPanel
Orientation="Horizontal"
Margin="0,5,0,0">
<Label
Content="Job Details"
FontWeight="Bold"
FontSize="24"></Label>
</StackPanel>
<StackPanel
Orientation="Horizontal">
<Line
StrokeThickness="3"></Line>
</StackPanel>
<StackPanel
Orientation="Horizontal"
Margin="0,5,0,0">
<Label
Content="Date: "
FontWeight="Bold"
Width="110" />
<TextBox
Text="{Binding JobDate, Mode=OneWay}"
Width="200" />
</StackPanel>
<StackPanel
Orientation="Horizontal"
Margin="0,5,0,0">
<Label
Content="Waste Type: "
FontWeight="Bold"
Width="110" />
<ComboBox
x:Name="CboWasteTypes"
IsEditable="False"
ItemsSource="{Binding Path=WasteTypeData}"
DisplayMemberPath="WasteType"
SelectedValuePath="WasteTypeID"
SelectedValue="{Binding WasteTypeID}"
Width="200" />
</StackPanel>
<StackPanel
Orientation="Horizontal"
Margin="0,5,0,0">
<Label
Content="Status: "
FontWeight="Bold"
Width="110" />
<TextBox
Text="{Binding Status, Mode=OneWay}"
Width="200" />
</StackPanel>
</StackPanel>
</StackPanel>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</UserControl>
Thanks
Paul

Answer 1

Check the Output window for any binding errors. You may have misspelled something or not set the DataContext correctly.

Answer 2

I think its failing because when you use {Binding Path=WasteTypeData} in your combobox, it expects to find it as a property in JobsItems instead of the observable collection, since that is what the parent control (your ListBox) is bound to.
Add WasteTypeData as a static resource in your user control, then bind your combobox to that, specifying it using "{Binding Source={StaticResource..."
<UserControl
...
xmlns:local="WorkItems"
...
Height="300" Width="500">
<UserControl.Resources>
<local:WasteTypeData x:Key="WasteTypeData"/>
</UserControl.Resources>
..
<ComboBox
x:Name="CboWasteTypes"
IsEditable="False"
ItemsSource="{Binding Source={StaticResource WasteTypeData}}"
DisplayMemberPath="WasteType"
SelectedValuePath="WasteTypeID"
SelectedValue="{Binding WasteTypeID}"
Width="200" />
See if that helps!