Delphi XE8: TEdit TextHint Disappears When Receiving Focus - delphi

Question

Basically, I want the TextHint of my TEdits to disappear when the first character is entered and not when they receive focus, like the Edits on this Microsoft page: Sign in to your Microsoft account. Can someone please walk me through on how to achieve this?
Thank you in advance.

Answer 1

The built-in TEdit behavior doesn't allow this, but you can derive a new control from TEdit and override DoSetTextHint. The implementation should be similar to the internal method, but provide a value of 1 for wParam instead of 0.
This is a solution using an interceptor class:
unit EditInterceptor;
uses
Vcl.StdCtrls, System.SysUtils, Winapi.Messages, Windows;
type
TEdit = class(Vcl.StdCtrls.TEdit)
protected
procedure DoSetTextHint(const Value: string); override;
end;
implementation
uses
Vcl.Themes, Winapi.CommCtrl;
procedure TEdit.DoSetTextHint(const Value: string);
begin
if CheckWin32Version(5, 1) and StyleServices.Enabled and HandleAllocated then
SendTextMessage(Handle, EM_SETCUEBANNER, WPARAM(1), Value);
end;
end.
Make sure to place this unit in the interface uses clause after Vcl.StdCtrls.

Answer 2

Based on Uwe Raabe's answer, here is a procedure (for Delphi 2007, should work for newer versions of Delphi as well):
type
TCueBannerHideEnum = (cbhHideOnFocus, cbhHideOnText);
procedure TEdit_SetCueBanner(_ed: TEdit; const _s: WideString; _WhenToHide: TCueBannerHideEnum = cbhHideOnFocus);
const
EM_SETCUEBANNER = $1501;
var
wParam: Integer;
begin
case _WhenToHide of
cbhHideOnText: wParam := 1;
else // cbhHideOnFocus: ;
wParam := 0;
end;
SendMessage(_ed.Handle, EM_SETCUEBANNER, wParam, Integer(PWideChar(_s)));
end;
You call it like this:
constructor TForm1.Create(_Owner: TComponent);
begin
inherited;
TEdit_SetCueBanner(ed_HideOnFocus, 'hide on focus', cbhHideOnFocus);
TEdit_SetCueBanner(ed_HideOnText, 'hide on text', cbhHideOnText);
end;
It doesn't check for the Windows version though, you might want to add the if statement Uwe provided:
if CheckWin32Version(5, 1) and StyleServices.Enabled and _ed.HandleAllocated then
I just tested it with a project where I disabled runtime theming: It didn't work.