DP44/enriched-qwen3-coder-next/Common/DTS.Common/Events/DTS.Viewer/Reports.md

source_files, generated_at, model, schema_version, sha256

source_files	generated_at	model	schema_version	sha256
Common/DTS.Common/Events/DTS.Viewer/Reports/SaveReportToCSVRequestedEvent.cs Common/DTS.Common/Events/DTS.Viewer/Reports/SaveReportToPDFRequestedEvent.cs	2026-04-16T03:27:02.713322+00:00	Qwen/Qwen3-Coder-Next-FP8	1	c23355273750380a

Reports

Documentation: Report Export Request Events

1. Purpose

This module defines Prism-based pub/sub events used to signal user-initiated requests to export report data to external formats—specifically CSV and PDF. These events decouple the UI layer (e.g., a report viewer control or dialog) from the export implementation logic, enabling loose coupling and testability in the MVVM pattern. When a user selects "Save as CSV" or "Save as PDF", the UI publishes the corresponding event, and a dedicated handler (e.g., in a service or view model) subscribes to perform the actual file I/O and export processing.

2. Public Interface

• SaveReportToCSVRequestedEvent
  Type: class inheriting from PubSubEvent<SaveReportToCSVRequestedEventArgs>
  Behavior: A Prism event used to publish requests to save a report to CSV format. Subscribers receive an instance of SaveReportToCSVRequestedEventArgs containing the target directory and parent view model context.

• SaveReportToCSVRequestedEventArgs
  Type: class
  Properties:

  • Directory (string): The file system directory where the CSV file should be saved.
  • ParentVM (IBaseViewModel): The view model that initiated or owns the report context (e.g., the active report view model). Used for context-aware operations (e.g., resolving data sources or parent window handles).

• SaveReportToPDFRequestedEvent
  Type: class inheriting from PubSubEvent<SaveReportToPDFRequestedEventArgs>
  Behavior: A Prism event used to publish requests to save a report to PDF format. Subscribers receive an instance of SaveReportToPDFRequestedEventArgs with the same payload structure as the CSV variant.

• SaveReportToPDFRequestedEventArgs
  Type: class
  Properties:

  • Directory (string): The file system directory where the PDF file should be saved.
  • ParentVM (IBaseViewModel): The view model that initiated or owns the report context.

Note: Both event argument classes are mutable (public setters on properties) and lack validation or immutability guarantees.

3. Invariants

• The Directory property in both argument types is expected to be a valid, writable file system path at the time of event publication.
• The ParentVM property is expected to be non-null at event publication; however, no explicit null-checking or enforcement is present in the event argument classes themselves.
• Events are published before export logic executes (i.e., they are request triggers, not completion notifications).
• No ordering guarantees exist between multiple subscribers—concurrent or conflicting writes to the same path are possible if not handled by subscribers.

4. Dependencies

• Internal Dependencies:
  • DTS.Common.Base.IBaseViewModel: Defines the contract for view models used in the parent context.
  • Prism.Events.PubSubEvent<T>: Prism’s event aggregation infrastructure.
• External Dependencies:
  • System and System.Collections.Generic, System.Linq, System.Text, System.Threading.Tasks: Standard .NET libraries.
• Consumers (inferred):
  • UI components (e.g., report viewer controls) that publish these events on user action.
  • Export service classes or view models that subscribe to these events to handle file generation.
  • Likely used in conjunction with IBaseViewModel implementations that expose report data and coordinate with export services.

5. Gotchas

• No filename specification: The event arguments only provide a directory, not a filename. Subscribers must derive filenames (e.g., via timestamp, report name from ParentVM, or user input), which may lead to inconsistent naming or overwrites if not handled carefully.
• No cancellation support: Events lack a mechanism to signal cancellation (e.g., via CancellationToken) or to abort the operation mid-process.
• No error propagation: Exceptions thrown by subscribers are not captured or propagated back to the publisher; error handling must be implemented entirely within subscribers.
• No format-specific metadata: Arguments do not include export options (e.g., CSV delimiter, PDF page size, inclusion of headers). Subscribers must hardcode or infer such settings.
• Mutable payload: Since Directory and ParentVM have public setters, subscribers could inadvertently modify the event args—though this is unlikely to be intentional.
• None identified from source alone.