Add Drag and Drop For Environment Variables

[Darkace01]

Summary of the Pull Request

This PR introduces drag-and-drop functionality for environment variables, allowing users to easily update the order of variables based on their preferences. Users can now rearrange variables directly in the UI by dragging and dropping, making it more intuitive and efficient to customise the order without manual editing.

PR Checklist

• Closes: Environment Variables - allow changing order of paths by dragging #33554 33554
• Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end-user-facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Updated EnvironmentVariablesMainPage.xaml to use a ListView instead of an ItemsControl, enabling item dragging and reordering. The new ListView features a grid layout with a FontIcon, TextBox, and Button, while maintaining visibility control through data binding.

Added EditVariableValuesList_DragItemsCompleted method in EnvironmentVariablesMainPage.xaml.cs to update the text box with the new order of items after drag-and-drop operations, ensuring consistency with the underlying data model.

Validation Steps Performed

• Manually tested the affected functionality.
• Change was minimal and did not impact existing automated tests.
• Verified that the new/modified feature works as expected and did not cause regressions in related areas.

[Darkace01]

@microsoft-github-policy-service agree

[Copilot]

Pull Request Overview

This pull request adds drag-and-drop support to the environment variables UI, enabling users to rearrange variables more intuitively. Key changes include:

• Introducing a constant (ValueListSeparator) and updating join calls in EnvironmentVariablesMainPage.xaml.cs.
• Replacing an ItemsControl with a ListView in EnvironmentVariablesMainPage.xaml to support dragging and reordering.
• Adding the EditVariableValuesList_DragItemsCompleted event handler to update the UI upon reordering.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/modules/EnvironmentVariables/EnvironmentVariablesUILib/EnvironmentVariablesMainPage.xaml.cs	Updated join logic with a constant and added a new drag completion event handler.
src/modules/EnvironmentVariables/EnvironmentVariablesUILib/EnvironmentVariablesMainPage.xaml	Replaced ItemsControl with a ListView enabling drag-and-drop functionality.

[dcq01]

Hi! I'm a grad student working on a research project about using large language models to automate code review. Based on your commit a0e65cb and the changes in src/modules/EnvironmentVariables/EnvironmentVariablesUILib/EnvironmentVariablesMainPage.xaml.cs, my tool generated this comment:

1. Null Handling: Ensure that variable and variable.ValuesList are not null before attempting to join the values. If either is null, handle this case explicitly.

   if (variable == null || variable.ValuesList == null) {
       // Handle the null case appropriately
       return;
   }

2. Potential for IndexOutOfRange: Implement additional checks to ensure that the index is valid before attempting to move items in ReorderButtonDown_Click and ReorderButtonUp_Click.

3. Event Unsubscription and Subscription: Use a try-finally block to ensure that the event handler is always reattached after setting the text of EditVariableDialogValueTxtBox.

   EditVariableDialogValueTxtBox.TextChanged -= EditVariableDialogValueTxtBox_TextChanged;
   try {
       EditVariableDialogValueTxtBox.Text = newValues;
   } finally {
       EditVariableDialogValueTxtBox.TextChanged += EditVariableDialogValueTxtBox_TextChanged;
   }

4. Consistency of Separator: Ensure that the ValueListSeparator is consistently used throughout the codebase wherever the values are joined. If there are other parts of the code that still use the hardcoded ";" separator, it could lead to inconsistencies in how values are represented.

5. TextBox Event Handling: Ensure that the event EditVariableDialogValueTxtBox.TextChanged is not being triggered unnecessarily. If the new value is the same as the current value, it might be better to avoid setting the text and modifying the event handlers.

6. Potential Performance Impact: If ValuesList contains a large number of items, consider using string.Join directly on the Select without converting to an array to avoid performance implications.
   Change:

   var newValues = string.Join(ValueListSeparator, variable.ValuesList?.Select(x => x.Text).ToArray());

   to:

   var newValues = string.Join(ValueListSeparator, variable.ValuesList?.Select(x => x.Text));

7. Code Duplication: The code for creating newValues is duplicated across multiple methods. Consider refactoring this into a separate method to adhere to the DRY (Don't Repeat Yourself) principle.

   private void UpdateValuesTextBox(Variable variable)
   {
       var newValues = string.Join(ValueListSeparator, variable.ValuesList?.Select(x => x.Text));
       EditVariableDialogValueTxtBox.TextChanged -= EditVariableDialogValueTxtBox_TextChanged;
       EditVariableDialogValueTxtBox.Text = newValues;
       EditVariableDialogValueTxtBox.TextChanged += EditVariableDialogValueTxtBox_TextChanged;
   }

8. User Experience: When inserting a new ValuesListItem with an empty string, consider how this affects the user experience. If the user is not expecting an empty entry, it might be better to prompt them or handle it differently.

9. Unit Tests for ValueListSeparator: Add unit tests to verify the behavior of the code when using the ValueListSeparator constant. Ensure it is correctly used in all relevant methods.

As part of my research, I'm trying to understand how useful these comments are in real-world development. If you have a moment, I'd be super grateful if you could quickly reply to these two yes/no questions:

1. Does this comment provide suggestions from a dimension you hadn’t considered?
2. 2. Do you find this comment helpful?

Thanks a lot for your time and feedback! And sorry again if this message is a bother.