Input, commands, and clipboard
The native control owns typing, marked text, candidate interaction, primary selection, and touch handles. Hardware key bindings route commands; they do not replace the platform input connection.
On Android, keyboards receive up to 8,192 UTF-16 units of surrounding text. Autofill is unavailable for document values longer than 65,536 units. These limits do not truncate documents, saved files, or clipboard content.
Use the control's Commands, KeyBindings, and ContextMenuOpening APIs for application UI. Rich-editor methods include CopyAsync, CutAsync, PasteAsync, PastePlainTextAsync, Undo, Redo, and SelectAll. IsReadOnly is a session editing policy. Direct document edits are independent of one view's read-only state.
Composition
Marked text lives in a provisional session snapshot. The shared committed document does not change until native composition completes. A document permits one composition lease; unrelated mutation is rejected with CompositionActive. Other panes may still inspect and display committed content.
With multiple carets, native composition previews at the primary caret, including its virtual column. Virtual padding becomes document text only when input commits. A simple committed replacement is replicated to the other carets in one transaction. Reconversion extending outside the primary range leaves secondary-selection mode. Cancellation restores the pre-composition selection set.
Request completion before saving, changing documents, or commands requiring committed input. An unresolved request must remain pending rather than saving text that omits the marked input.
Source input rules
CodeEditor.InputRules.Register installs synchronous transaction-planning callbacks in explicit priority and registration order. A TextInputContext exposes the before/input snapshots, selections, and input changes. Its replacements address the input candidate; overlapping rule edits are rejected.
Use rules for paired delimiters, completion commit characters, indentation, and linked placeholders. Rules cannot await or mutate the live document. A completion plus commit character belongs to one plan and one undo unit. Async language analysis supplies cached decisions or later revision-checked edits.
Clipboard
Rich clipboard exchange is self-contained RTF plus ordinary plain-text fallback. Android uses an RTF transport that cooperating applications can read. Unsupported external rich payloads use available plain text; no HTML codec is provided.
Cut freezes the selection and snapshot, publishes the clipboard, then checks document revision and selection generation before deleting. An asynchronous stale cut cannot delete newly selected or edited content.
In-process multiple-selection metadata can preserve fragment boundaries while clipboard identity matches. Matching fragment/caret counts distribute fragments; otherwise the combined payload is inserted at each selection. External rich interchange remains one RTF payload.
Drag and drop
On Windows, dragging selected text copies it to a drop destination. Rich selections carry RTF and ordinary text; source selections carry exact text. Dropping into an editor uses its paste event and editing limits. A drop is canceled if its destination document, selection, or attached view changes while the data is being read. Dragging does not replace the system clipboard.