CRUD operations with an unknown type - wpf

Question

I am trying to make a program that gives you a CRUD interface for List of any objects you give it. That includes:
Showing all of their properties inside a ListBox
The ability to insert a new object
The ability to update an object
The ability to delete an object
Keep in mind that, at the compile-time, I have no idea what kind of objects I am getting. For example, I want to have a TextBlock for each of the properties simply listed inside ListBox's DataTemplate. So how would I do the data binding if I don't know the name of the property? Also, how would I generate an insertion form when I don't know property names?
And finally, is it possible to do it using pure MVVM Pattern, without any Code-Behind?
Thanks

Answer 1

One option: Wrap PropertyInfo in a PropertyInfoViewModel so you can bind to it's value:
class PropertyInfoViewModel
{
Object CRUDObject { get; set; }
PropertyInfo PropertyInfo { get; set; }
Object Value {
get
{
return PropertyInfo.GetValue(CRUDObject);
}
set
{
PropertyInfo.SetValue(CRUDObject, value);
}
}
}
You could have an ObservableCollection in your CRUDObjectViewModel, populated when you create it or change the CRUD it's attached to (Look up reflection if confused by this).
Use a template selector to choose a particular editor to display for the PropertyInfoViewModel:
public class PropertyTypeTemplateSelector : DataTemplateSelector
{
public DataTemplate BooleanTemplate { get; set; }
public DataTemplate GuidTemplate { get; set; }
public DataTemplate StringTemplate { get; set; }
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
PropertyInfo propertyInfo = (item as PropertyInfoViewModel).PropertyInfo;
if (propertyInfo.PropertyType == typeof(Boolean))
{
return BooleanTemplate;
}
else if (propertyInfo.PropertyType == typeof(Guid))
{
return GuidTemplate;
}
else if (propertyInfo.PropertyType == typeof(String))
{
return StringTemplate;
}
return null;
}
}
You could use it like this:
<ListBox ItemsSource="{Binding Properties}">
<ListBox.Resources>
<DataTemplate x:Key="BooleanTemplate">
<CheckBox Content="{Binding PropertyInfo.Name}" IsChecked="{Binding Value}"/>
</DataTemplate>
<DataTemplate x:Key="GuidTemplate">
<StackPanel>
<TextBox Text="{Binding PropertyInfo.Name}"/>
<TextBox Text="{Binding Value, ValueConverter={StaticResources MyGuidConverter}}"/>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="StringTemplate">
<StackPanel>
<TextBox Text="{Binding PropertyInfo.Name}"/>
<TextBox Text="{Binding Value}"/>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="Null"/>
</ListBox.Resources>
<ListBox.ItemTemplateSelector>
<helpers:PropertyTypeTemplateSelector BooleanTemplate="{StaticResource BooleanTemplate}"
GuidTemplate="{StaticResource GuidTemplate}"
StringTemplate="{StaticResource StringTemplate}"/>
</ListBox.ItemTemplateSelector>
</ListBox>
Might have to think about how to deal with changes/updates though, as this isn't using NotifyPropertyChanged to keep the UI up to date.
I've not tested any of this, but it should work, I think.

Answer 2

This control WPFCrudControl may fit with your problem.
A generic WPF CrudControl implemented based on the MVVM pattern. It gives a huge productivity boost for straightforward CRUD operations (Add, Edit, Delete, Validate, Listing with sorting, paging and searching). The control abstracts both the UI and business logic, so it requires relatively minimal coding effort, while keeping it possible to customize its behavior.