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Comments on C# WPF datagrid not persisting inserts
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C# WPF datagrid not persisting inserts
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I am working with VS 2022 and trying to make a WPF MVVM application. The application updates the items displayed in the datagrid, persisting the changes to the database upon save. However, adding a new record to the grid does not insert (without extra steps). I imagine I am missing something simple.
It seems to me as if since the updates persist from the ObservableCollection to the context without extra coding then the inserts would also.
View:
<Window x:Class="PictureWar.View.TagTagTypeWindow"
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:PictureWar.View"
mc:Ignorable="d"
Title="Tags and TagTypes" Height="450" Width="800">
<Window.Resources>
<CollectionViewSource x:Key="tagTypeViewSource" Source="{Binding TagTypes}"/>
<CollectionViewSource x:Key="tagTagTypesViewSource"
Source="{Binding Tags, Source={StaticResource tagTypeViewSource}}"/>
</Window.Resources>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<DataGrid Grid.Row="0" Grid.Column="0" x:Name="tagTypesDataGrid" AutoGenerateColumns="False"
EnableRowVirtualization="True"
ItemsSource="{Binding Source={StaticResource tagTypeViewSource}}"
Margin="0,0,0,0" RowDetailsVisibilityMode="VisibleWhenSelected">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding ID}"
Header="Tag Type Id"
Width="SizeToHeader"
IsReadOnly="True"/>
<DataGridTextColumn Binding="{Binding Name}"
Header="Name"
Width="*"/>
</DataGrid.Columns>
</DataGrid>
<DataGrid Grid.Row="0" Grid.Column="1" x:Name="tagsDataGrid" AutoGenerateColumns="False"
EnableRowVirtualization="True"
ItemsSource="{Binding Source={StaticResource tagTagTypesViewSource}}"
Margin="0,0,0,0" RowDetailsVisibilityMode="VisibleWhenSelected"
RenderTransformOrigin="0.488,0.251">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding ID}"
Header="Tag Id"
Width="SizeToHeader"
IsReadOnly="True"/>
<DataGridTextColumn Binding="{Binding TagTypeID}"
Header="Tag Type Id"
Width="SizeToHeader"
IsReadOnly="False"/>
<DataGridTextColumn Binding="{Binding Name}" Header="Name" Width="*"/>
</DataGrid.Columns>
</DataGrid>
<Button Grid.Row="2" Grid.ColumnSpan="2" Command="{Binding SaveCommand}">Save</Button>
</Grid>
Code Behind
public partial class TagTagTypeWindow : Window
{
public TagTagTypeWindow()
{
InitializeComponent();
DataContext = new TagTagTypeViewModel();
}
}
View Model
namespace PictureWar.ViewModel;
public class TagTagTypeViewModel : ObservableObject
{
private ObservableCollection<TagType> _tagTypes;
private readonly TagTypeRepository _repository;
public TagTagTypeViewModel()
{
_repository = new TagTypeRepository();
_tagTypes = new ObservableCollection<TagType>(_repository.GetAllTagTypes().ToList());
SaveCommand = new RelayCommand(DoSave);
}
public IRelayCommand SaveCommand { get; }
public ObservableCollection<TagType> TagTypes
{
get => _tagTypes;
set { SetProperty(ref _tagTypes, value); }
}
public void DoSave()
{
var newTagTypes = TagTypes.Where(tt => tt.ID < 1); //extra step
_repository.SaveAllTagTypes(newTagTypes);
}
}
Repository
public class TagTypeRepository
{
private readonly WarContext _context;
public TagTypeRepository()
{
_context = new WarContext();
}
public IEnumerable<TagType> GetAllTagTypes()
{
return _context.TagType.Include(tt => tt.Tags);
}
public void SaveAllTagTypes(IEnumerable<TagType> newTagTypes)
{
_context.TagType.AddRange(newTagTypes); //part of the extra step
_context.SaveChanges();
}
}
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