WPF page binding failing - wpf

Question

I was hoping someone would be kind enough to steer me in the right direction.
I’m trying to get my head around WPF.
I’ve created a 4.8 framework application with two buttons and a frame on the main window. I’m using Caliburn.Micro for binding – This is my test application to try and understand it.
When you press the first button, the window context is set to a page, with an Employees data grid upon it. The data is fed from a back end Oracle Database (I’m trying to follow the MVVM pattern.) This works perfectly.
When you press the other button, the main window displays a second page within the frame – This time, Departments. This much works. I have a an unbound textbox in the page and this shows as it should.
The part I have spent two days trying to get to work is the data grid for the Departments. It returns blank.
I know for certain that the Departments variable is being populated. I have confirmed this two ways. I have stepped through the code and can see values being populated. I have also placed the code below in the Employee page and had the data grid display with values.
I have also tried to display the employees data grid within the Departments page but it too is blank at run time.
To the best of my ability to discern, the code behind the two pages is identical aside from the obvious name change.
This is from my Departments View Model:
using Caliburn.Micro;
using DataLibrary;
namespace WpfEmployees.ViewModels
{
public class DepartmentsViewModel : Screen
{
public BindableCollection<DepartmentsModel> Departments { get; set; }
public DepartmentsViewModel()
{
DepartmentsProcessor dp = new DepartmentsProcessor();
Departments = new BindableCollection<DepartmentsModel>(dp.LoadDepartments());
}
}
}
From the view:
<DataGrid x:Name="Departments" ></DataGrid>
I'm not seeing any error messages, just a blank data grid.
Any suggestions of where I might look for my error would be very much appreciated.

Answer 1

To get this to work:
Main window:
<Window x:Class="WpfEmployees.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfEmployees"
xmlns:viewmodels="clr-namespace:WpfEmployees.ViewModels"
xmlns:views="clr-namespace:WpfEmployees.Views"
mc:Ignorable="d"
Title="MainWindow" Height="850" Width="650" Loaded="ShowDepartmentsPage">
<Window.Resources>
<DataTemplate x:Name="employeesViewTemplate" DataType="{x:Type viewmodels:EmployeesViewModel}">
<views:EmployeesView DataContext="{Binding}"/>
</DataTemplate
<DataTemplate x:Name="departmentsViewTemplate" DataType="{x:Type viewmodels:DepartmentsViewModel}">
<views:DepartmentsView DataContext="{Binding}"/>
</DataTemplate>
</Window.Resources>
<Grid>
...
<Button x:Name="ShowEmployeesBtn" Content="Employees"
Margin="10 0 0 0" Click="ShowEmployeesPage"/>
<Button x:Name="ShowDepartmentsBtn" Content="Departments"
Margin="10 0 0 0" Click="ShowDepartmentsPage" />
...
<ContentControl Content="{Binding}"/>
</Grid>
</Window>
Main window class button code
public partial class MainWindow
{
...
private void ShowEmployeesPage(object sender, RoutedEventArgs e)
{
DataContext = new EmployeesViewModel();
}
View Model Code
public class EmployeesViewModel
...
public ObservableCollection<EmployeesModel> ObEmployees { get; set; }
...
public EmployeesViewModel()
{
EmployeesProcessor ep = new EmployeesProcessor();
ObEmployees = new ObservableCollection<EmployeesModel>
(ep.LoadEmployees());
}
I don't know if this is the best route. It works but I'm too new at WPF to know. I'm hoping this is what Ed Plunkett had in mind, so it may be. Thank you again, Ed.