How to implement ScintillaNET column edit mode - winforms

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.