Added support for binding to sub-objects in ComboBoxColumn

[filipwa84]

Issue: #2738

PR Type

What kind of change does this PR introduce?

• Feature

What is the current behavior?

Binding cannot be bound to sub-objects and throws an exception.

What is the new behavior?

Support for binding to sub-objects has been added.

PR Checklist

Please check if your PR fulfills the following requirements:

• [x ] Tested code with current supported SDKs
• [x ] Pull Request has been submitted to the documentation repository instructions. Link:
• [x ] Sample in sample app has been added / updated (for bug fixes / features)
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• [x ] Contains NO breaking changes

Other information

[filipwa84]

@RBrid Would you be able to review this pull request for me?

[filipwa84]

@RBrid Hi Regis, would you have time to look at this one please?

[RBrid]

Sorry for the long delay Filip. There is already a file with a bunch of type utility functions: ...\WindowsCommunityToolkit\Microsoft.Toolkit.Uwp.UI.Controls.DataGrid\Utilities\TypeHelper.cs

• Can you please check if any of those methods can be used instead of yours?
• Any new method should be added to that file (if any is still required) instead of DataGridComboBoxColumn.cs. And if you add some to that file it's better to make them bullet proof with input parameter checks.

Thanks!

[filipwa84]

@rbird Thanks for the comments. Will look in to it next week and replace with methods from TypeHelper.cs

[RBrid]

Thanks for looking into this Filip.

[RBrid]

Thanks for the changes Filip.

[filipwa84]

@michael-hawker Any chance of getting another reviewer to approve this pull request? :)

[michael-hawker]

@filipwa84 sorry this fell off my radar with the holidays. Régis' approval is the main gate, looks good to me.

Is there anything in the sample page that should be updated to show off this new feature?

[filipwa84]

@michael-hawker Nothing that needs to be shown in the sample app in my opinion. The added functionality just adds the possibility to bind to sub-objects which is an expected behavior.

[michael-hawker]

@filipwa84 sorry for the delay on this, any advice on framing for testing this feature?

Also, it appears there's a merge conflict now, would you mind resolving?

Thanks!

[filipwa84]

@michael-hawker I'll take a look at it

[filipwa84]

@michael-hawker The merge conflict is resolved.

Regarding testing, you can just verify that the column's Binding property can be bound to a property within a sub-object. For example:

<controls:DataGrid AutoGenerateColumns="False"
			        ItemsSource="{x:Bind MyModels, Mode=OneWay}"
				SelectedItem="{x:Bind SelectedMyModel, Mode=TwoWay}">
	<controls:DataGrid.Columns>
		<controls:DataGridComboBoxColumn Binding="{Binding MySubModel.DisplayId}" ItemsSource="{x:Bind Displays}" DisplayMemberPath="Text"/>
	</controls:DataGrid.Columns>

</controls:DataGrid>

where MySubModel is a "sub-object" inside MyModels which has a property called DisplayId which we are matching to a property with the same name inside Displays.

[filipwa84]

@michael-hawker any chance of getting this merged? :) We rely on this being fixed in our project...

[michael-hawker]

@filipwa84 yup, I'll get this merged for 6.1, just haven't had time to test things out, thanks for the example. I'll use that and take a look, thanks a bunch!

[michael-hawker]

Thanks for the contribution @filipwa84! Sorry this took so long to merge and missed the last release. It'll be 6.1 though! 🎉🎉🎉

[filipwa84]

@michael-hawker Thank you. Just a quick question, should this be available in the NuGet preview package now? Tried to install 6.1 preview but it seemed like it wasn't there...

[michael-hawker]

@filipwa84 I think this was merged after we did the preview package for //Build. You can grab it from MyGet, those are updated as soon as it gets merged to Master automatically.

6.1 should ship on Monday though! 🤞

Thanks again for this contribution! 🎉🎉🎉