---
title: Preview a document
summary: Renders a document from a package/XML pair through the xPression Design service without printing or distributing it.
status: draft
owner: SAIF Documentation
last_reviewed: 2026-09-01
library: SAIF.Services.Printing
reference_type: embedded
operation_id: op-01-preview-a-document
trigger: clsPrint.previewDocument invoked
---

# Preview a document

Renders a document from a package name and xPression data XML through the xPression Design web service, returning the rendered bytes for preview purposes without printing or distributing the result.

| Field | Value |
| --- | --- |
| **Operation ID** | OP-01 |
| **Trigger** | `clsPrint.previewDocument` invoked (two public overloads: `(inPackage, inXML)` or `(inPackage, inXML, inOutputProfile)`) |
| **Inputs** | Package name, xPression data XML, optional output profile (defaults to `"PDF"` when not supplied) |
| **Outputs** | Rendered document bytes (`Byte()`) |
| **Primary components** | `clsPrint.previewDocument` (public overloads), private `previewDocument()`, `m_Xpresso.previewDocument` |
| **Entry point** | `SAIF.Services.Printing/clsPrint.vb` |

## Steps

1. The public 2-argument overload trims and assigns `inPackage` to the `Package` property. The package name is normalized by stripping a trailing `.pkg` extension via the `Package` setter ([BR-PRT-001](../business-rules.md#br-prt-001-package-name-extension-normalization)).
2. Assigns `inXML` to the `XML` property unchanged — no transformation is applied.
3. The 3-argument overload additionally assigns `inOutputProfile` to the `OutputProfile` property, overriding the `"PDF"` default that would otherwise apply.
4. Both public overloads delegate to the private parameterless `previewDocument()`, which calls `m_Xpresso.previewDocument(m_Package, m_XML, m_OutputProfile, m_Application)` against the xPression Design web service.
5. The bytes returned by the web service are returned to the caller unchanged — there is no caching and no success/failure flag distinct from the returned bytes.

## Process flow

```mermaid
flowchart TD
	Start(["previewDocument invoked"]) --> Norm["Normalize package name"]
	Norm --> SetXML["Set XML<br>(and OutputProfile<br>if 3-arg overload)"]
	SetXML --> Call["Call m_Xpresso.<br>previewDocument<br>via xPression<br>Design service"]
	Call --> End(["Return rendered bytes"])
```

## Failure and edge-case behavior
- There is no try/catch around the web service call; a `SoapException` or `WebException` raised by `m_Xpresso.previewDocument` propagates directly to the caller, unlike the non-throwing pattern used by `ReportBase` ([BR-PRT-010](../business-rules.md#br-prt-010-non-throwing-render-and-distribute-failures) describes that separate, non-throwing pattern; this operation does not use it).
- The 2-argument overload does not set `OutputProfile` — whichever value was last set on the instance (or the `"PDF"` default) is used silently, with no indication to the caller that an implicit value is in effect.

## Related documentation
- [Index](../index.md)
- [Overview](../overview.md)
- [Architecture](../architecture.md)
- [Dependencies](../dependencies.md)
- [Operations and processes](../operations-processes.md)
- [Business rules](../business-rules.md)
- [Configuration](../configuration.md)
- [API reference](../api/index.md)

## Sources
- `SAIF.Services.Printing/clsPrint.vb`