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Loading and saving documents

Load a document​

Set Source to a file path and the viewer loads it. DocumentSource is the bindable alternative when the source may be a file path string, a Stream or a byte[]. A string given to DocumentSource is routed through Source, so in-place saving still works. From code, call LoadDocumentAsync.

// From a file path
await Viewer.LoadDocumentAsync("/path/to/document.pdf");

// From a stream
await using var stream = File.OpenRead("/path/to/document.pdf");
await Viewer.LoadDocumentAsync(stream);

// From bytes in memory
byte[] bytes = await File.ReadAllBytesAsync("/path/to/document.pdf");
await Viewer.LoadDocumentAsync(bytes);
MethodDescription
LoadDocumentAsync(string path, string? password = null)Loads a PDF from a file path.
LoadDocumentAsync(Stream stream, string? password = null)Loads a PDF from a stream. The stream is read from its current position, or from the start if it is seekable and at its end.
LoadDocumentAsync(ReadOnlyMemory<byte> data, string? password = null)Loads a PDF from bytes in memory. A whole array is used in place; a slice is copied.
CloseDocument()Closes the current document and releases its native state.
ClearError()Clears ErrorMessage. An open document stays open.

DocumentLoaded is raised when a document finishes loading, with PageCount and Metadata in its args. LoadError is raised when loading fails. The message is also shown on the canvas and on the bindable ErrorMessage property.

Viewer.DocumentLoaded += (_, e) =>
    Title = $"{e.Metadata.Title} ({e.PageCount} pages)";

Viewer.LoadError += (_, e) =>
    Console.WriteLine($"Load failed: {e.Message}");

Password-protected documents​

Pass the password to LoadDocumentAsync, or set Password before setting Source. If an encrypted document is loaded without a password, the viewer prompts for one and lets the user retry.

await Viewer.LoadDocumentAsync("/path/to/encrypted.pdf", password: "secret");

Document permissions​

A PDF can forbid annotation, form filling, copying or printing. With RespectDocumentPermissions set to true (the default), the viewer withholds each of those features when the document forbids it. A document opened with its owner password is unrestricted. Set RespectDocumentPermissions to false to ignore the flags.

The document's flags are exposed on the Permissions property as PdfPermissions, with CanPrint, CanPrintHighQuality, CanModify, CanCopyContent, CanAnnotate, CanFillForms, CanExtractForAccessibility and CanAssemble. It is null while no document is open.

Your own gates are separate:

PropertyEffect
IsReadOnlyDisables annotation and form editing in one switch. Tools are disarmed, and selected annotations cannot be moved or deleted.
AllowTextSelectionEnables text selection and copy.
AllowAnnotationEditingEnables creating and editing annotations.
AllowFormEditingEnables interactive form field editing.
AllowDocumentSavingEnables saving. Gates SaveCommand and SaveAsync.

CanEditAnnotations reports the combined result: not IsReadOnly, AllowAnnotationEditing is true, and the document allows it when RespectDocumentPermissions is on.

Save a document​

Every save writes the document with its annotation edits, form values, redactions and bookmarks.

MethodDescription
SaveAsync() / Save()Saves in place over Source. Honours AllowDocumentSaving. A document loaded from a stream or byte array has no path: SaveAsync throws InvalidOperationException and Save() reports it through ErrorMessage.
SaveDocumentAsync(string filePath)Saves to a path.
SaveDocumentAsync(Stream stream)Saves to a stream.
SaveAsAsync() / SaveAs()Shows the platform save picker and writes the document to the chosen file, or raises SaveAsRequested.
// Save a copy
await Viewer.SaveDocumentAsync("/path/to/output.pdf");

// Save to a stream
await using var output = new MemoryStream();
await Viewer.SaveDocumentAsync(output);

IsDirty is true while the document has unsaved edits. It is cleared by a successful save and by loading another document.

Set AutoSave to true to write back to Source after each annotation, form or redaction edit. This requires AllowDocumentSaving and a document loaded from a path.

Signed documents​

A document with digital signatures is saved as an incremental update, so the signed revision stays intact and readers can still verify it. Other documents are rewritten in full.

Open, Save and Save As menu entries​

The More Options menu can also show Open, Save and Save As entries. They are off by default. Opt in per entry with IsOpenVisible, IsSaveVisible and IsSaveAsVisible.

  • Open shows the platform file picker and loads the chosen file. A file with a local path is opened by path, so in-place saving works. Where the picker gives no path (the browser, some mobile pickers), the file is read through a stream.
  • Save saves in place. The entry is hidden while AllowDocumentSaving is false, and disabled for a document loaded from a stream.
  • Save As shows the platform save picker and writes the document with its edits. If the user picks another local file, the viewer switches to that file and keeps the current page.

All three are also available as Open(), OpenAsync(), SaveAs(), SaveAsAsync(), OpenCommand and SaveAsCommand, whether or not the menu shows them.

Use your own dialogs​

Handle OpenRequested or SaveAsRequested and set Handled to true to replace the built-in pickers. PdfSaveAsRequestedEventArgs.GetDocumentBytesAsync() returns the PDF to write.

Viewer.SaveAsRequested += async (_, e) =>
{
    e.Handled = true;
    var pdf = await e.GetDocumentBytesAsync();
    await myDocumentStore.SaveAsync(pdf);
};

Lifecycle​

  • Detaching the viewer from the visual tree, for example when switching tabs, keeps the document, its unsaved edits, the undo history, the current page and the zoom. They come back when it is re-attached.
  • Source can be set before the viewer is attached. The document is drawn once it is.
  • Closing the window releases the native document. So does CloseDocument().
  • A Stream passed to the viewer is read once and never disposed, so dispose it yourself after the load call returns. A byte[] is used in place for the document's lifetime and must not be modified while the document is open.

See also​

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