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