C# TextEditorData.EnsureCaretIsNotVirtual方法代码示例

		public static void SetCompletionText (TextEditorData data, CodeCompletionContext ctx, string partialWord, string completeWord, int wordOffset)
		{
			if (data == null || data.Document == null)
				return;

			int triggerOffset = ctx.TriggerOffset;
			int length = String.IsNullOrEmpty (partialWord) ? 0 : partialWord.Length;

			// for named arguments invoke(arg:<Expr>);
			if (completeWord.EndsWith (":", StringComparison.Ordinal)) {
				if (data.GetCharAt (triggerOffset + length) == ':')
					length++;
			}

			bool blockMode = false;
			if (data.IsSomethingSelected) {
				blockMode = data.MainSelection.SelectionMode == Mono.TextEditor.SelectionMode.Block;
				if (blockMode) {
					data.Caret.PreserveSelection = true;
					triggerOffset = data.Caret.Offset - length;
				} else {
					if (data.SelectionRange.Offset < ctx.TriggerOffset)
						triggerOffset = ctx.TriggerOffset - data.SelectionRange.Length;
					data.DeleteSelectedText ();
				}
				length = 0;
			}

			// | in the completion text now marks the caret position
			int idx = completeWord.IndexOf ('|');
			if (idx >= 0) {
				completeWord = completeWord.Remove (idx, 1);
			}
			
			triggerOffset += data.EnsureCaretIsNotVirtual ();
			if (blockMode) {
				using (var undo = data.OpenUndoGroup ()) {

					int minLine = data.MainSelection.MinLine;
					int maxLine = data.MainSelection.MaxLine;
					int column = triggerOffset - data.Document.GetLineByOffset (triggerOffset).Offset;
					for (int lineNumber = minLine; lineNumber <= maxLine; lineNumber++) {
						DocumentLine lineSegment = data.Document.GetLine (lineNumber);
						if (lineSegment == null)
							continue;
						int offset = lineSegment.Offset + column;
						data.Replace (offset, length, completeWord);
					}
					int minColumn = Math.Min (data.MainSelection.Anchor.Column, data.MainSelection.Lead.Column);
					data.MainSelection = data.MainSelection.WithRange (
						new Mono.TextEditor.DocumentLocation (data.Caret.Line == minLine ? maxLine : minLine, minColumn),
						data.Caret.Location
					);

					data.Document.CommitMultipleLineUpdate (data.MainSelection.MinLine, data.MainSelection.MaxLine);
					data.Caret.PreserveSelection = false;
				}
			} else {
				data.Replace (triggerOffset, length, completeWord);
			}
			
			data.Document.CommitLineUpdate (data.Caret.Line);
			if (idx >= 0)
				data.Caret.Offset = triggerOffset + idx;

		}

		static int PastePlainText (TextEditorData data, int offset, string text, bool preserveSelection = false)
		{
			int inserted = 0;
			using (var undo = data.OpenUndoGroup ()) {
				var version = data.Document.Version;
				if (!preserveSelection)
					data.DeleteSelectedText (!data.IsSomethingSelected || data.MainSelection.SelectionMode != SelectionMode.Block);
				data.EnsureCaretIsNotVirtual ();
				if (data.IsSomethingSelected && data.MainSelection.SelectionMode == SelectionMode.Block) {
					var selection = data.MainSelection;
					var visualInsertLocation = data.LogicalToVisualLocation (selection.Anchor);
					for (int lineNumber = selection.MinLine; lineNumber <= selection.MaxLine; lineNumber++) {
						var lineSegment = data.GetLine (lineNumber);
						int insertOffset = lineSegment.GetLogicalColumn (data, visualInsertLocation.Column) - 1;
						string textToInsert;
						if (lineSegment.Length < insertOffset) {
							int visualLastColumn = lineSegment.GetVisualColumn (data, lineSegment.Length + 1);
							int charsToInsert = visualInsertLocation.Column - visualLastColumn;
							int spaceCount = charsToInsert % data.Options.TabSize;
							textToInsert = new string ('\t', (charsToInsert - spaceCount) / data.Options.TabSize) + new string (' ', spaceCount) + text;
							insertOffset = lineSegment.Length;
						} else {
							textToInsert = text;
						}
						inserted = data.Insert (lineSegment.Offset + insertOffset, textToInsert);
					}
				} else {
					offset = version.MoveOffsetTo (data.Document.Version, offset);
					inserted = data.PasteText (offset, text);
				}
			}
			return inserted;
		}

		static void NewLineSmartIndent (TextEditorData data)
		{
			using (var undo = data.OpenUndoGroup ()) {
				data.EnsureCaretIsNotVirtual ();
				data.InsertAtCaret (data.EolMarker);
				data.InsertAtCaret (data.GetIndentationString (data.Caret.Location));
			}
		}

		public static void InsertNewLine (TextEditorData data)
		{
			if (!data.CanEditSelection)
				return;
			
			using (var undo = data.OpenUndoGroup ()) {
				if (data.IsSomethingSelected)
					data.DeleteSelectedText ();
				switch (data.Options.IndentStyle) {
				case IndentStyle.None:
					data.InsertAtCaret (data.EolMarker);
					break;
				case IndentStyle.Auto:
					data.EnsureCaretIsNotVirtual ();
					var sb = new StringBuilder (data.EolMarker);
					sb.Append (data.Document.GetLineIndent (data.Caret.Line));
					data.InsertAtCaret (sb.ToString ());
					break;
				case IndentStyle.Smart:
					if (!data.HasIndentationTracker)
						goto case IndentStyle.Auto;
					NewLineSmartIndent (data);
					break;
				case IndentStyle.Virtual:
					if (!data.HasIndentationTracker)
						goto case IndentStyle.Auto;
					var oldLine = data.Caret.Line;
					var curLine = data.GetLine (oldLine);
					var indentCol = data.GetVirtualIndentationColumn (data.Caret.Location);
					if (curLine.Length >= data.Caret.Column) {
						NewLineSmartIndent (data);
						data.FixVirtualIndentation ();
						data.FixVirtualIndentation (oldLine);
						break;
					}
					data.Insert (data.Caret.Offset, data.EolMarker);
					data.FixVirtualIndentation (oldLine);
					data.Caret.Column = indentCol;
					break;
				default:
					throw new ArgumentOutOfRangeException ();
				}
			}
		}

		public static void CaretLineToEnd (TextEditorData data)
		{
			if (!data.CanEdit (data.Caret.Line))
				return;
			LineSegment line = data.Document.GetLine (data.Caret.Line);
			data.EnsureCaretIsNotVirtual ();
			if (data.Caret.Column == line.EditableLength) {
				// Nothing after the cursor, delete the end-of-line sequence
				data.Remove (line.Offset + data.Caret.Column, line.Length - data.Caret.Column);
			} else {
				// Delete from cursor position to the end of the line
				data.Remove (line.Offset + data.Caret.Column, line.EditableLength - data.Caret.Column);
			}
			data.Document.CommitLineUpdate (data.Caret.Line);
		}

		public static void InsertNewLine (TextEditorData data)
		{
			if (!data.CanEditSelection)
				return;
			
			using (var undo = data.OpenUndoGroup ()) {
				if (data.IsSomethingSelected) {
					var end = data.MainSelection.End;
					data.DeleteSelectedText ();
					if (end.Column == 1) {
						CaretMoveActions.InternalCaretMoveHome (data, true, false);
						return;
					}
				}
				switch (data.Options.IndentStyle) {
				case IndentStyle.None:
					data.InsertAtCaret (data.EolMarker);
					break;
				case IndentStyle.Auto:
					data.EnsureCaretIsNotVirtual ();
					var indent = data.Document.GetLineIndent (data.Caret.Line);
					data.InsertAtCaret (data.EolMarker);
					data.EnsureCaretIsNotVirtual ();
					if (data.GetLine (data.Caret.Line).Length == 0)
						data.InsertAtCaret (indent);
					break;
				case IndentStyle.Smart:
					if (!data.HasIndentationTracker)
						goto case IndentStyle.Auto;
					NewLineSmartIndent (data);
					break;
				case IndentStyle.Virtual:
					if (!data.HasIndentationTracker)
						goto case IndentStyle.Auto;
					var oldLine = data.Caret.Line;
					var curLine = data.GetLine (oldLine);
					var indentCol = data.GetVirtualIndentationColumn (data.Caret.Location);
					if (curLine.Length >= data.Caret.Column) {
						NewLineSmartIndent (data);
						data.FixVirtualIndentation ();
						data.FixVirtualIndentation (oldLine);
						break;
					}
					data.Insert (data.Caret.Offset, data.EolMarker);
					data.FixVirtualIndentation (oldLine);
					data.Caret.Column = indentCol;
					break;
				default:
					throw new ArgumentOutOfRangeException ();
				}
			}
		}

		public static void Backspace (TextEditorData data, Action<TextEditorData> removeCharBeforeCaret)
		{
			if (!data.CanEditSelection)
				return;
			using (var undo = data.OpenUndoGroup ()) {
				if (data.IsSomethingSelected) {
					var visualAnchorLocation = data.LogicalToVisualLocation (data.MainSelection.Anchor);
					var visualLeadLocation = data.LogicalToVisualLocation (data.MainSelection.Lead);
					// case: zero width block selection
					if (data.MainSelection.SelectionMode == SelectionMode.Block && visualAnchorLocation.Column == visualLeadLocation.Column) {
						var col = data.MainSelection.Lead.Column;
						if (col <= DocumentLocation.MinColumn) {
							data.ClearSelection ();
							return;
						}
						bool preserve = data.Caret.PreserveSelection;
						data.Caret.PreserveSelection = true;
						for (int lineNumber = data.MainSelection.MinLine; lineNumber <= data.MainSelection.MaxLine; lineNumber++) {
							var lineSegment = data.Document.GetLine (lineNumber);
							int insertOffset = lineSegment.GetLogicalColumn (data, visualAnchorLocation.Column - 1) - 1;
							data.Remove (lineSegment.Offset + insertOffset, 1);
						}

						var visualColumn = data.GetLine (data.Caret.Location.Line).GetVisualColumn (data, col - 1);
						data.MainSelection = new Selection (
							new DocumentLocation (data.MainSelection.Anchor.Line, data.GetLine (data.MainSelection.Anchor.Line).GetLogicalColumn (data, visualColumn)),
							new DocumentLocation (data.MainSelection.Lead.Line, data.GetLine (data.MainSelection.Lead.Line).GetLogicalColumn (data, visualColumn)),
							SelectionMode.Block
						);

						data.Caret.PreserveSelection = preserve;
						data.Document.CommitMultipleLineUpdate (data.MainSelection.MinLine, data.MainSelection.MaxLine);
						return;
					}
					data.DeleteSelectedText (data.MainSelection.SelectionMode != SelectionMode.Block);
					return;
				}

				if (data.Caret.Line == DocumentLocation.MinLine && data.Caret.Column == DocumentLocation.MinColumn)
					return;
			
				// Virtual indentation needs to be fixed before to have the same behavior
				// if it's there or not (otherwise user has to press multiple backspaces in some cases)
				data.EnsureCaretIsNotVirtual ();
				DocumentLine line = data.Document.GetLine (data.Caret.Line);
				if (data.Caret.Column > line.Length + 1) {
					data.Caret.Column = line.Length + 1;
				} else if (data.Caret.Offset == line.Offset) {
					DocumentLine lineAbove = data.Document.GetLine (data.Caret.Line - 1);
					if (lineAbove.Length == 0 && data.HasIndentationTracker && data.Options.IndentStyle == IndentStyle.Virtual) {
						data.Caret.Location = new DocumentLocation (data.Caret.Line - 1, data.IndentationTracker.GetVirtualIndentationColumn (data.Caret.Line - 1, 1));
						data.Replace (lineAbove.EndOffsetIncludingDelimiter - lineAbove.DelimiterLength, lineAbove.DelimiterLength, data.IndentationTracker.GetIndentationString (data.Caret.Line - 1, 1));
					} else {
						data.Remove (lineAbove.EndOffsetIncludingDelimiter - lineAbove.DelimiterLength, lineAbove.DelimiterLength);
					}
				} else {
					removeCharBeforeCaret (data);
				}

				// Needs to be fixed after, the line may just contain the indentation
				data.FixVirtualIndentation ();
			}
		}

		static int PasteFrom (Clipboard clipboard, TextEditorData data, bool preserveSelection, int insertionOffset, bool preserveState)
		{
			int result = -1;
			if (!data.CanEdit (data.Document.OffsetToLineNumber (insertionOffset)))
				return result;
			if (clipboard.WaitIsTargetAvailable (CopyOperation.MD_ATOM)) {
				clipboard.RequestContents (CopyOperation.MD_ATOM, delegate(Clipboard clp, SelectionData selectionData) {
					if (selectionData.Length > 0) {
						byte[] selBytes = selectionData.Data;
	
						string text = System.Text.Encoding.UTF8.GetString (selBytes, 1, selBytes.Length - 1);
						bool pasteBlock = (selBytes [0] & 1) == 1;
						bool pasteLine = (selBytes [0] & 2) == 2;
						
//						var clearSelection = data.IsSomethingSelected ? data.MainSelection.SelectionMode != SelectionMode.Block : true;
						if (pasteBlock) {
							using (var undo = data.OpenUndoGroup ()) {
								var version = data.Document.Version;
								data.DeleteSelectedText (!data.IsSomethingSelected || data.MainSelection.SelectionMode != SelectionMode.Block);
								data.EnsureCaretIsNotVirtual ();
								insertionOffset = version.MoveOffsetTo (data.Document.Version, insertionOffset);

								data.Caret.PreserveSelection = true;
							
								string[] lines = text.Split ('\r');
								int lineNr = data.Document.OffsetToLineNumber (insertionOffset);
								int col = insertionOffset - data.Document.GetLine (lineNr).Offset;
								int visCol = data.Document.GetLine (lineNr).GetVisualColumn (data, col);
								DocumentLine curLine;
								int lineCol = col;
								result = 0;
								for (int i = 0; i < lines.Length; i++) {
									while (data.Document.LineCount <= lineNr + i) {
										data.Insert (data.Document.TextLength, Environment.NewLine);
										result += Environment.NewLine.Length;
									}
									curLine = data.Document.GetLine (lineNr + i);
									if (lines [i].Length > 0) {
										lineCol = curLine.GetLogicalColumn (data, visCol);
										if (curLine.Length + 1 < lineCol) {
											result += lineCol - curLine.Length;
											data.Insert (curLine.Offset + curLine.Length, new string (' ', lineCol - curLine.Length));
										}
										data.Insert (curLine.Offset + lineCol, lines [i]);
										result += lines [i].Length;
									}
									if (!preserveState)
										data.Caret.Offset = curLine.Offset + lineCol + lines [i].Length;
								}
								if (!preserveState)
									data.ClearSelection ();
								data.Caret.PreserveSelection = false;
							}
						} else if (pasteLine) {
							using (var undo = data.OpenUndoGroup ()) {
								data.DeleteSelectedText (!data.IsSomethingSelected || data.MainSelection.SelectionMode != SelectionMode.Block);
								data.EnsureCaretIsNotVirtual ();

								data.Caret.PreserveSelection = true;
								result = text.Length;
								DocumentLine curLine = data.Document.GetLine (data.Caret.Line);
								data.Insert (curLine.Offset, text + data.EolMarker);
								if (!preserveState)
									data.ClearSelection ();
								data.Caret.PreserveSelection = false;
							}
						} else {
							result = PastePlainText (data, insertionOffset, text);
						}
					}
				});
				// we got MD_ATOM text - no need to request text. (otherwise buffer may get copied twice).
				return result;
			}
			
			if (result < 0 && clipboard.WaitIsTextAvailable ()) {
				clipboard.RequestText (delegate(Clipboard clp, string text) {
					if (string.IsNullOrEmpty (text))
						return;
					using (var undo = data.OpenUndoGroup ()) {
						result = PastePlainText (data, insertionOffset, text);
					}
				});
			}
			
			return result;
		}

		public static void Backspace (TextEditorData data, Action<TextEditorData> removeCharBeforeCaret)
		{
			if (!data.CanEditSelection)
				return;
			if (data.IsSomethingSelected) {
				// case: zero width block selection
				if (data.MainSelection.SelectionMode == SelectionMode.Block && data.MainSelection.Anchor.Column == data.MainSelection.Lead.Column) {
					var col = data.MainSelection.Lead.Column;
					if (col <= DocumentLocation.MinColumn) {
						data.ClearSelection ();
						return;
					}
					bool preserve = data.Caret.PreserveSelection;
					data.Caret.PreserveSelection = true;
					col--;
					for (int lineNumber = data.MainSelection.MinLine; lineNumber <= data.MainSelection.MaxLine; lineNumber++) {
						data.Remove (data.Document.GetLine (lineNumber).Offset + col - 1, 1);
					}
					data.MainSelection.Lead = new DocumentLocation (data.MainSelection.Lead.Line, col);
					data.MainSelection.Anchor = new DocumentLocation (data.MainSelection.Anchor.Line, col);
					data.Caret.PreserveSelection = preserve;
					data.Document.CommitMultipleLineUpdate (data.MainSelection.MinLine, data.MainSelection.MaxLine);
					return;
				}
				data.DeleteSelectedText (data.MainSelection.SelectionMode != SelectionMode.Block);
				return;
			}

			if (data.Caret.Line == DocumentLocation.MinLine && data.Caret.Column == DocumentLocation.MinColumn)
				return;
			
			// Virtual indentation needs to be fixed before to have the same behavior
			// if it's there or not (otherwise user has to press multiple backspaces in some cases)
			data.EnsureCaretIsNotVirtual ();
			DocumentLine line = data.Document.GetLine (data.Caret.Line);
			if (data.Caret.Column > line.Length + 1) {
				data.Caret.Column = line.Length + 1;
			} else if (data.Caret.Offset == line.Offset) {
				DocumentLine lineAbove = data.Document.GetLine (data.Caret.Line - 1);
				data.Remove (lineAbove.EndOffsetIncludingDelimiter - lineAbove.DelimiterLength, lineAbove.DelimiterLength);
			} else {
				removeCharBeforeCaret (data);
			}

			// Needs to be fixed after, the line may just contain the indentation
			data.FixVirtualIndentation ();
		}

		public static void CaretLineToEnd (TextEditorData data)
		{
			if (!data.CanEdit (data.Caret.Line))
				return;
			var line = data.Document.GetLine (data.Caret.Line);

			using (var undo = data.OpenUndoGroup ()) {
				data.EnsureCaretIsNotVirtual ();
				int physColumn = data.Caret.Column - 1;
				if (physColumn == line.Length) {
					// Nothing after the cursor, delete the end-of-line sequence
					data.Remove (line.Offset + physColumn, line.LengthIncludingDelimiter - physColumn);
				} else {
					// Delete from cursor position to the end of the line
					var end = GetEndOfLineOffset (data, data.Caret.Location, false);
					data.Remove (line.Offset + physColumn, end - (line.Offset + physColumn));
				}
			}
			data.Document.CommitLineUpdate (data.Caret.Line);
		}

		public static void CaretLineToStart (TextEditorData data)
		{
			if (!data.CanEdit (data.Caret.Line))
				return;
			var line = data.Document.GetLine (data.Caret.Line);

			using (var undo = data.OpenUndoGroup ()) {
				data.EnsureCaretIsNotVirtual ();
				int physColumn = data.Caret.Column - 1;

				var startLine = GetStartOfLineOffset (data, data.Caret.Location);
				data.Remove (startLine, (line.Offset + physColumn) - startLine);
			}

			data.Document.CommitLineUpdate (data.Caret.Line);
		}

		static int PasteFrom (Clipboard clipboard, TextEditorData data, bool preserveSelection, int insertionOffset, bool preserveState)
		{
			int result = -1;
			if (!data.CanEdit (data.Document.OffsetToLineNumber (insertionOffset)))
				return result;
			if (clipboard.WaitIsTargetAvailable (CopyOperation.MD_ATOM)) {
				clipboard.RequestContents (CopyOperation.MD_ATOM, delegate(Clipboard clp, SelectionData selectionData) {
					if (selectionData.Length > 0) {
						byte[] selBytes = selectionData.Data;
						var upperBound = System.Math.Max (0, System.Math.Min (selBytes [1], selBytes.Length - 2));
						byte[] copyData = new byte[upperBound];
						Array.Copy (selBytes, 2, copyData, 0, copyData.Length);
						var rawTextOffset = 1 + 1 + copyData.Length;
						string text = Encoding.UTF8.GetString (selBytes, rawTextOffset, selBytes.Length - rawTextOffset);
						bool pasteBlock = (selBytes [0] & 1) == 1;
						bool pasteLine = (selBytes [0] & 2) == 2;
						if (pasteBlock) {
							using (var undo = data.OpenUndoGroup ()) {
								var version = data.Document.Version;
								if (!preserveSelection)
									data.DeleteSelectedText (!data.IsSomethingSelected || data.MainSelection.SelectionMode != SelectionMode.Block);
								int startLine = data.Caret.Line;
								data.EnsureCaretIsNotVirtual ();
								insertionOffset = version.MoveOffsetTo (data.Document.Version, insertionOffset);

								data.Caret.PreserveSelection = true;
								var lines = new List<string> ();
								int offset = 0;
								while (true) {
									var delimiter = LineSplitter.NextDelimiter (text, offset);
									if (delimiter.IsInvalid)
										break;

									int delimiterEndOffset = delimiter.EndOffset;
									lines.Add (text.Substring (offset, delimiter.Offset - offset));
									offset = delimiterEndOffset;
								}
								if (offset < text.Length)
									lines.Add (text.Substring (offset, text.Length - offset));

								int lineNr = data.Document.OffsetToLineNumber (insertionOffset);
								int col = insertionOffset - data.Document.GetLine (lineNr).Offset;
								int visCol = data.Document.GetLine (lineNr).GetVisualColumn (data, col);
								DocumentLine curLine;
								int lineCol = col;
								result = 0;
								for (int i = 0; i < lines.Count; i++) {
									while (data.Document.LineCount <= lineNr + i) {
										data.Insert (data.Document.TextLength, Environment.NewLine);
										result += Environment.NewLine.Length;
									}
									curLine = data.Document.GetLine (lineNr + i);
									if (lines [i].Length > 0) {
										lineCol = curLine.GetLogicalColumn (data, visCol);
										if (curLine.Length + 1 < lineCol) {
											result += lineCol - curLine.Length;
											data.Insert (curLine.Offset + curLine.Length, new string (' ', lineCol - curLine.Length));
										}
										data.Insert (curLine.Offset + lineCol, lines [i]);
										result += lines [i].Length;
									}
									if (!preserveState)
										data.Caret.Offset = curLine.Offset + lineCol + lines [i].Length;
								}
								if (!preserveState)
									data.ClearSelection ();
								data.FixVirtualIndentation (startLine); 
								data.Caret.PreserveSelection = false;
							}
						} else if (pasteLine) {
							using (var undo = data.OpenUndoGroup ()) {
								if (!preserveSelection)
									data.DeleteSelectedText (!data.IsSomethingSelected || data.MainSelection.SelectionMode != SelectionMode.Block);
								data.EnsureCaretIsNotVirtual ();

								data.Caret.PreserveSelection = true;
								result = text.Length;
								DocumentLine curLine = data.Document.GetLine (data.Caret.Line);

								result = PastePlainText (data, curLine.Offset,  text + data.EolMarker, preserveSelection, copyData);
								if (!preserveState)
									data.ClearSelection ();
								data.Caret.PreserveSelection = false;
								data.FixVirtualIndentation (curLine.LineNumber); 
							}
						} else {
							result = PastePlainText (data, insertionOffset, text, preserveSelection, copyData);
						}
					}
				});
				// we got MD_ATOM text - no need to request text. (otherwise buffer may get copied twice).
				return result;
			}
			
			if (result < 0 && clipboard.WaitIsTextAvailable ()) {
				clipboard.RequestText (delegate(Clipboard clp, string text) {
					if (string.IsNullOrEmpty (text))
						return;
					result = PastePlainText (data, insertionOffset, text, preserveSelection);
				});
//.........这里部分代码省略.........

		static void NewLineSmartIndent (TextEditorData data)
		{
			using (var undo = data.OpenUndoGroup ()) {
				data.EnsureCaretIsNotVirtual ();
				data.InsertAtCaret (data.EolMarker);
				var line = data.Document.GetLine (data.Caret.Line);
				data.InsertAtCaret (data.GetIndentationString (line.EndOffset));
			}
		}

		public static void Paste (TextEditorData data)
		{
			if (!data.CanEditSelection)
				return;
			using (var undo = data.OpenUndoGroup ()) {
				data.EnsureCaretIsNotVirtual ();
				PasteFrom (Clipboard.Get (CopyOperation.CLIPBOARD_ATOM), data, true, data.IsSomethingSelected ? data.SelectionRange.Offset : data.Caret.Offset);
			}
		}

		public static void Delete (TextEditorData data)
		{
			if (!data.CanEditSelection)
				return;

			using (var undoGroup = data.OpenUndoGroup ()) {
				if (data.IsSomethingSelected) {
					// case: zero width block selection
					if (data.MainSelection.SelectionMode == SelectionMode.Block && data.MainSelection.Anchor.Column == data.MainSelection.Lead.Column) {
						var col = data.MainSelection.Lead.Column;
						if (col <= DocumentLocation.MinColumn) {
							data.ClearSelection ();
							return;
						}
						bool preserve = data.Caret.PreserveSelection;
						data.Caret.PreserveSelection = true;
						col--;
						for (int lineNumber = data.MainSelection.MinLine; lineNumber <= data.MainSelection.MaxLine; lineNumber++) {
							DocumentLine lineSegment = data.Document.GetLine (lineNumber);
							if (col < lineSegment.Length)
								data.Remove (lineSegment.Offset + col, 1);
						}
						data.Caret.PreserveSelection = preserve;
						data.Document.CommitMultipleLineUpdate (data.MainSelection.MinLine, data.MainSelection.MaxLine);
						return;
					}
					data.DeleteSelectedText (data.MainSelection.SelectionMode != SelectionMode.Block);
					return;
				}
				if (data.Caret.Offset >= data.Document.TextLength)
					return;

				data.EnsureCaretIsNotVirtual ();

				DocumentLine line = data.Document.GetLine (data.Caret.Line);
				if (data.Caret.Column == line.Length + 1) {
					if (data.Caret.Line < data.Document.LineCount) { 
						data.Remove (line.EndOffsetIncludingDelimiter - line.DelimiterLength, line.DelimiterLength);
						if (line.EndOffsetIncludingDelimiter == data.Document.TextLength)
							line.UnicodeNewline = UnicodeNewline.Unknown;
					}
				} else {
					data.Remove (data.Caret.Offset, 1); 
					data.Document.CommitLineUpdate (data.Caret.Line);
				}
				data.FixVirtualIndentation ();
			}
		}