// ......................................................
//
// Handling Text Input
//
// ......................................................
/// <summary>
/// This is a single method used to insert user input characters.
/// It takes care of typing undo, springload formatting, overtype mode etc.
/// </summary>
/// <param name="This"></param>
/// <param name="textData">
/// Text to insert.
/// </param>
/// <param name="isInsertKeyToggled">
/// Reflects a state of Insert key at the moment of textData input.
/// </param>
/// <param name="acceptControlCharacters">
/// True indicates that control characters like '\t' or '\r' etc. can be inserted.
/// False means that all control characters are filtered out.
/// </param>
private static void DoTextInput(TextEditor This, string textData, bool isInsertKeyToggled, bool acceptControlCharacters)
{
// Hide the mouse cursor on user input.
HideCursor(This);
// Remove control characters. Note that this is not included into _FilterText,
// because we want such kind of filtering only for real input,
// not for copy/paste.
if (!acceptControlCharacters)
{
for (int i = 0; i < textData.Length; i++)
{
if (Char.IsControl(textData[i]))
{
textData = textData.Remove(i--, 1); // decrement i to compensate for character removal
}
}
}
string filteredText = This._FilterText(textData, This.Selection);
if (filteredText.Length == 0)
{
return;
}
TextEditorTyping.OpenTypingUndoUnit(This);
UndoCloseAction closeAction = UndoCloseAction.Rollback;
try
{
using (This.Selection.DeclareChangeBlock())
{
This.Selection.ApplyTypingHeuristics(This.AllowOvertype && This._OvertypeMode && filteredText != "\t");
This.SetSelectedText(filteredText, InputLanguageManager.Current.CurrentInputLanguage);
// Create caret position normalized backward to keep formatting of a character just typed
ITextPointer caretPosition = This.Selection.End.CreatePointer(LogicalDirection.Backward);
// Set selection at the end of input content
This.Selection.SetCaretToPosition(caretPosition, LogicalDirection.Backward, /*allowStopAtLineEnd:*/true, /*allowStopNearSpace:*/true);
// Note: Using explicit backward orientation we keep formatting with
// a previous character during typing.
closeAction = UndoCloseAction.Commit;
}
}
finally
{
TextEditorTyping.CloseTypingUndoUnit(This, closeAction);
}
}
// Helper for plain text filtering when pasted into rich or plain destination
private static bool PastePlainText(TextEditor This, string pastedText)
{
pastedText = This._FilterText(pastedText, This.Selection);
if (pastedText.Length > 0)
{
if (This.AcceptsRichContent && This.Selection.Start is TextPointer)
{
// Clear selection content
This.Selection.Text = String.Empty;
// Ensure that text is insertable at current selection
TextPointer start = TextRangeEditTables.EnsureInsertionPosition((TextPointer)This.Selection.Start);
// Store boundaries of inserted text
start = start.GetPositionAtOffset(0, LogicalDirection.Backward);
TextPointer end = start.GetPositionAtOffset(0, LogicalDirection.Forward);
// For rich text we need to remove control characters and
// replace linebreaks by paragraphs
int currentLineStart = 0;
for (int i = 0; i < pastedText.Length; i++)
{
if (pastedText[i] == '\r' || pastedText[i] == '\n')
{
end.InsertTextInRun(pastedText.Substring(currentLineStart, i - currentLineStart));
if (!This.AcceptsReturn)
{
return true; // All lined except for the first one are ignored when TextBox does not accept Return key
}
if (end.HasNonMergeableInlineAncestor)
{
// We cannot split a Hyperlink or other non-mergeable Inline element,
// so insert a space character instead (similar to embedded object).
// Note that this means, Paste operation would loose
// paragraph break information in this case.
end.InsertTextInRun(" ");
}
else
{
end = end.InsertParagraphBreak();
}
if (pastedText[i] == '\r' && i + 1 < pastedText.Length && pastedText[i + 1] == '\n')
{
i++;
}
currentLineStart = i + 1;
}
}
end.InsertTextInRun(pastedText.Substring(currentLineStart, pastedText.Length - currentLineStart));
// Select all pasted content
This.Selection.Select(start, end);
}
else
{
// For plain text we insert the content as is (including control characters)
This.Selection.Text = pastedText;
}
return true;
}
return false;
}
// Helper for OnEnterBreak for plain text case
private static bool HandleEnterBreakForPlainText(TextEditor This)
{
bool wasSelectionChanged = true;
// Filter Environment.NewLine based on TextBox.MaxLength
string filteredText = This._FilterText(Environment.NewLine, This.Selection);
if (filteredText != String.Empty)
{
This.Selection.Text = Environment.NewLine;
}
else
{
// Do not update selection if Environment.NewLine can not fit in.
wasSelectionChanged = false;
}
return wasSelectionChanged;
}