How to implement ScintillaNET column edit mode

Question

I need a text editor control for column edit in my application.

Like notepad++ alt+mouse drag to select a text block , or pull down a long vertical cursor and press a key to insert a char to every lines over cursor.

I tried ScintillaNET but it not suppor the column-modet for insert, just can remove selected text block

I need below effect(notepad++), But ScintillaNET got:

Answer 1

I found a way to solve. Still using ScintillaNET.

But coding not enough beauty :)

class SelWrap
{
    public int Begin { get; set; }
    public int Length { get; set; }
}

//...

editor.KeyDown += (s, e) =>
{
    // filter alt we will hold down alt to make vertical selection
    if (e.Alt) return;

    var tb = editor;
    if (tb.Selections.Count < 2) return; // no in column mode

    e.SuppressKeyPress = true; //block input, handle by below code

    //refered from post #5825820
    var input = Utility.GetCharFromKey(e.KeyCode).ToString();
    if (input == "\0")
    {
        //SystemSounds.Beep.Play();
        return;
    }

    var array = tb.Selections
        .OrderBy(p => p.Start)
        .Select(p => new SelWrap{Begin=p.Start, Length=p.End - p.Start })
        .ToArray();

    //do process every caret(or selection)
    for (var i = 0; i < array.Length; i++)
    {
        var item = array[i];

        if (item.Length > 0) 
        {
            //if has selected text, just clean
            tb.DeleteRange(item.Begin, item.Length);

            for (var j = i + 1; j < array.Length; j++)
            {
                array[j].Begin -= item.Length;
            }
        }

        if (input == "\b") //backspace 
        {
            if (item.Length != 0) continue;

            //delete a char before caret
            tb.DeleteRange(item.Begin - 1, 1);

            for (var j = i; j < array.Length; j++)
            {
                array[j].Begin--;
            }
        }
        else //just insert that
        {
            tb.InsertText(item.Begin, input);

            for (var j = i; j < array.Length; j++)
            {
                array[j].Begin++;
            }
        }

    }

    //restore caret status to keep column mode
    tb.ClearSelections();
    tb.SetSelection(array[0].Begin, array[0].Begin);
    for (var i = 1; i < array.Length; i++)
    {
        var item = array[i];
        tb.AddSelection(item.Begin, item.Begin);
    }
};

//...

Answer 2

You need to turn on Scintilla rectangular selection by sending required messages to initialize rectangular selection. Example,

CallScintilla(SCI_SETSELECTIONMODE, SC_SEL_STREAM);
CallScintilla(SCI_SETMOUSESELECTIONRECTANGULARSWITCH, true);
CallScintilla(SCI_SETADDITIONALSELECTIONTYPING, true);  // so you can type in the selection
CallScintilla(SCI_SETMULTIPLESELECTION, false);
// on paste, paste into rectangular selection
CallScintilla(SCI_SETMULTIPASTE, SC_MULTIPASTE_EACH);

After that, it works like Visual Studio, you hold down the Alt key and drag with the mouse to start a rectangular selection.