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Loading and saving

Loading a document​

Set Source to a file path to have PdfViewer load the document at that path.

DocumentSource is the bindable alternative for when the source is 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);

DocumentLoaded is raised when a document finishes loading. It contains PageCount and Metadata in its arguments.

LoadError is raised if 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}");

Methods​

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.

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 (default), the viewer withholds each of those features if the document forbids it. If RespectDocumentPermissions is set to false, permission flags are ignored.

A document opened with its owner password is always unrestricted.

The document's flags are exposed on the Permissions property as PdfPermissions: CanPrint, CanPrintHighQuality, CanModify, CanCopyContent, CanAnnotate, CanFillForms, CanExtractForAccessibility and CanAssemble.

Your own permissions take precedence over the document's flags. For example, if you set AllowAnnotationEditing to true, then annotation is allowed and IsReadOnly is false, even if RespectDocumentPermissions is on.

PropertyEffect
IsReadOnlyDisables annotation and form editing. Tools are disarmed. 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.

Saving a document​

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

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

Set AutoSave to true to write back to Source after each annotation, form or redaction edit. This requires AllowDocumentSaving to be true.

// Save a copy
await Viewer.SaveDocumentAsync("/path/to/output.pdf");

// Save to a stream
await using var output = new MemoryStream();
await Viewer.SaveDocumentAsync(output);
MethodDescription
SaveAsync(), Save()Saves in place over Source. Honors AllowDocumentSaving. A document loaded from a stream or byte array has no path, so SaveAsync throws InvalidOperationException and Save() reports it through ErrorMessage.
SaveDocumentAsync(string filePath)Saves to the specified path.
SaveDocumentAsync(Stream stream)Saves to the specified stream.
SaveAsAsync(), SaveAs()Shows the platform's save dialog and writes the document to the chosen file, or raises SaveAsRequested.

Signed documents​

If a document carries digital signatures, it is saved as an incremental update, meaning the original signatures stay intact and are not invalidated by the save.

Unsigned documents are rewritten in full.

Open, Save and Save As menu entries​

The More Options menu can show Open, Save and Save As entries. They are disabled by default. Opt in to each with IsOpenVisible, IsSaveVisible and IsSaveAsVisible respectively.

  • Open shows the platform's file dialog and loads the chosen file.
  • Save saves to the source file path. This entry is hidden while AllowDocumentSaving is false. It is disabled for a document loaded from a stream.
  • Save As shows the platform save dialog and writes the document with any edits. If the user picks another local file, the viewer switches to that file and keeps the current page.
tip

Open and Save As operations are available via Open(), OpenAsync(), SaveAs(), SaveAsAsync(), OpenCommand and SaveAsCommand, whether or not the menu shows them.

Using your own dialogs​

To replace the platform's dialogs, handle OpenRequested or SaveAsRequested and set Handled to true. 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, together with its unsaved edits, undo history, current page and zoom. They come back when it is re-attached.
  • Source can be set before the viewer is attached. The document is drawn when it attaches.
  • Closing the window releases the native document, same as CloseDocument().
  • A Stream passed to the viewer is read once and never disposed. You can 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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