In Edit Feld künstlich einen Teil markieren

[Stevie]

Tja, das ist mal kein Delphi-Problem, sondern eins der API.

Die MSDN schrieb zu EM_SETSEL

The start value can be greater than the end value. The lower of the two values specifies the character position of the first character in the selection. The higher value specifies the position of the first character beyond the selection.
The start value is the anchor point of the selection, and the end value is the active end. If the user uses the SHIFT key to adjust the size of the selection, the active end can move but the anchor point remains the same.

P.S.: Ich hab da mal was gebastelt:

Delphi-Quellcode:

procedure SetSel(Edit: TEdit; Start, Stop: Integer);
var
  i: Integer;
  KeyboardState: TKeyboardState;
begin
  Edit.Perform(EM_SETSEL, Start, Start);
  GetKeyboardState(KeyboardState);
  KeyboardState[VK_SHIFT] := $80;
  SetKeyboardState(KeyboardState);
  if Start > Stop then
  for i := Start downto Succ(Stop) do
  begin
    Edit.Perform(WM_KEYDOWN, VK_LEFT, 0);
    Edit.Perform(WM_KEYUP, VK_LEFT, 0);
  end;
  if Start < Stop then
  for i := Start to Pred(Stop) do
  begin
    Edit.Perform(WM_KEYDOWN, VK_RIGHT, 0);
    Edit.Perform(WM_KEYUP, VK_RIGHT, 0);
  end;
  SetKeyboardState(KeyboardState);
end;