Post History

Datagrid in MVVM saves edits but not inserts

I am writing a todolist application in WPF with MVVM. I display the goals in a datagrid and the editing works fine. Changes made in the grid are saved to the DB when I click save. However, adding a new record does not persist during a save. Each goal may have subtasks associated with it that are handled in a detail row. Perhaps stranger, edits *and additions* to the subtasks **persist**.

When debugging, I found that the additions to the grid make it to the ObsdrvableCollection<Goal>, but they are not in the _context.Goals. Edits on existing records can be seen in both the ObservableCollection and in the _context.Goals. 

What do I need to change to get the additions into the _context?

I am using the Microsoft.Toolkit.Mvvm library.

    public class GoalsViewModel : ObservableObject
    ...
    _goals = new ObservableCollection<Goal>(_repository.GetAllGoals().ToList());
    ...
    public ObservableCollection<Goal> Goals
    {
        get => _goals;
        set { SetProperty(ref _goals, value); }
    }
    ...
    public void SaveAll()
    {
        _repository.SaveChanges();
    }

The repository SaveChanges() is merely _context.SaveChanges();

This is the view.

    <Window x:Class="TodoList.View.GoalsWindow"
       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:TodoList.View"
        mc:Ignorable="d"
        Title="Goals" Height="450" Width="800">
    <Window.Resources>
        <CollectionViewSource x:Key="goalsViewSource" Source="{Binding Goals}" />
        <CollectionViewSource x:Key="difficultyLevels" Source="{Binding DifficultyLevels}"/>
    </Window.Resources>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <DataGrid Grid.Column="0"
                  x:Name="goalsDataGrid"
                  AutoGenerateColumns="False" 
                  EnableRowVirtualization="True" 
                  IsReadOnly="False"
                  ScrollViewer.CanContentScroll="True" 
                  ScrollViewer.VerticalScrollBarVisibility="Auto"
                  ItemsSource="{Binding Source={StaticResource goalsViewSource}}" 
                  Margin="0,0,0,0" 
                  RowDetailsVisibilityMode="VisibleWhenSelected">
            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding ID}"
                            		Header="Id" 
									Width="SizeToCells"
                                    ElementStyle="{StaticResource NumericCell}"
                            		IsReadOnly="True" />
                <DataGridTemplateColumn Width="Auto">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <Button Content="Done!"
                                    Command="{Binding DataContext.MarkDoneCommand,
                                        RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}"
                                    CommandParameter="{Binding}"
                                    Margin="5" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
                <DataGridTextColumn Binding="{Binding Name}"
                            		Header="Name" 
									Width="75"
                            		IsReadOnly="False" />
                <DataGridTextColumn Binding="{Binding Description}"
                            		Header="Description" 
									Width="150"
                                    ElementStyle="{StaticResource WrappingText}"
                            		IsReadOnly="False" />
                <DataGridComboBoxColumn DisplayMemberPath="Name"
                                        SelectedValuePath="ID"
                                        ItemsSource="{Binding Source={StaticResource difficultyLevels}}"
                                        SelectedValueBinding="{Binding Path=DifficultyLevelID}"
                                        Header="Difficulty"
                                        Width="SizeToCells" />
                <DataGridTextColumn Binding="{Binding GoalItems.Count}" 
                                    Header="#Items" 
							        Width="SizeToHeader"
                                    ElementStyle="{StaticResource NumericCell}"
                                    IsReadOnly="True" />
                <DataGridTextColumn Binding="{Binding DateCreated, StringFormat='MM-dd-yyyy'}" 
                                    Header="Date Created" 
							        Width="SizeToHeader"
                                    IsReadOnly="True" />
                <DataGridTextColumn Binding="{Binding DateCompleted, StringFormat='MM-dd-yyyy'}" 
                                    Header="Date Completed" 
							        Width="SizeToHeader"
                                    IsReadOnly="True" />
            </DataGrid.Columns>
            <DataGrid.RowDetailsTemplate>
                <DataTemplate>
                    <DataGrid ItemsSource="{Binding GoalItems}" AutoGenerateColumns="False">
                        <DataGrid.Columns>
                            <DataGridCheckBoxColumn Binding="{Binding IsCompleted}"/>
                            <DataGridTextColumn Binding="{Binding Description}"/>
                        </DataGrid.Columns>
                    </DataGrid>
                </DataTemplate>
            </DataGrid.RowDetailsTemplate>
        </DataGrid>

        <Button Grid.Row="1" 
                Grid.Column="0" 
                Command="{Binding SaveAllCommand}" 
                Content="Save All Goals" />
    </Grid>
</Window>