Restore caret position, selection, and vertical scroll position

[Mihajlo]

Suppose I add from code some text to a shown document, like this:

try
{
    radRichTextEditor1.Document.History.IsEnabled = false;

    var editor = new RadDocumentEditor(radRichTextEditor1.Document);

    editor.Document.CaretPosition.MoveToLastPositionInDocument();
    editor.InsertParagraph();
    editor.Insert("XYZ");

    editor.Document.CaretPosition.MoveToFirstPositionInDocument();

    editor.Insert("ABC");
    editor.InsertParagraph();
}
finally
{
    radRichTextEditor1.Document.History.IsEnabled = true;
}

 

This code will destroy document's CaretPosition, Selection, and also user's view to the document (vertical scroll bar location). Is there a way to restore them to previous values?

 

[Boby]

Hello Mihajlo,

You can try to use what we call "tracking" document position, for example:

double originalOffset = radRichTextEditor1.VerticalOffset;
double originalY = this.radRichTextBox.Document.CaretPosition.Location.Y;
using (DocumentPosition originalCaretPosition = new DocumentPosition(this.radRichTextBox.Document.CaretPosition, true))
{
    try
    {
        radRichTextEditor1.Document.History.IsEnabled = false;

        var editor = new RadDocumentEditor(radRichTextEditor1.Document);

        editor.Document.CaretPosition.MoveToLastPositionInDocument();
        editor.InsertParagraph();
        editor.Insert("XYZ");

        editor.Document.CaretPosition.MoveToFirstPositionInDocument();

        editor.Insert("ABC");
        editor.InsertParagraph();
    }
    finally
    {
        radRichTextEditor1.Document.History.IsEnabled = true;
    }

    radRichTextEditor1.Document.CaretPosition.MoveToPosition(originalCaretPosition);
    radRichTextEditor1.ActiveEditorPresenter.ScrollToVerticalOffset(originalOffset - originalY + this.radRichTextBox.Document.CaretPosition.Location.Y);
    this.radRichTextBox.UpdateEditorLayout();

    radRichTextEditor1.Focus();
}

You can use the same method to preserve the regions of the DocumentSelection (RadRichTextEditor.Document.Selection).

Regards,
Boby
Progress Telerik