delphi - 如何重写调用以在 TEdit 中显示 CapsLock 提示窗口？

Question

基本上我有这个问题:CapsLock password message in TEdit visually fails with VCL Styles .

我想做的不是解决答案或评论中所示的问题。

我想完全禁用那个丑陋的提示窗口。而是显示一个图像，让用户知道大写字母已锁定。

像这样

Answer 1

我找到了问题的解决方案，它涉及到我不想使用的 hack。

事情是这样的。

1. 重写 WndProc。

代码

type
  TEdit = class (Vcl.StdCtrls.TEdit)
  protected
    procedure WndProc(var Message: TMessage); override;
  end;

拦截 EM_SHOWBALLOONTIP消息，您就完成了

代码

procedure TEdit.WndProc(var Message: TMessage);
begin
 if Message.Msg = EM_SHOWBALLOONTIP then
   showmessage('Do your thing.')
 else
  inherited;
end;

有关详细信息，请查看 MSDN 文档:

How do I suppress the CapsLock warning on password edit controls?

<小时/>

这是 TEdit 的后代，如果满足某个 FOnPasswordCaps ，则可以抑制密码编辑控件上的 CapsLock 警告。事件分配为 PasswordChar <> #0

unit NCREditUnit;

interface

uses
  Vcl.StdCtrls,
  vcl.Controls,
  Winapi.Messages,
  System.Classes;

type
  TNCREdit = class(TEdit)
  private
    FOnPasswordCapsLocked: TNotifyEvent;
    FIsCapsLocked: boolean;
    FOnPasswordCapsFreed: TNotifyEvent;
    FBlockCapsBalloonTip: boolean;
    FValuePasswordChrOnCaps: boolean;
    procedure SetOnPasswordCapsEvents;
    procedure SetOnPasswordCapsFreed(const aValue: TNotifyEvent);
    procedure SetOnPasswordCapsLocked(const aValue: TNotifyEvent);
  protected
    procedure WndProc(var Message: TMessage); override;
    procedure KeyUp(var Key: Word; Shift: TShiftState); override;
    procedure DoEnter; override;
    procedure DoExit; override;
  published
    property BlockCapsBalloonTip: boolean read FBlockCapsBalloonTip write FBlockCapsBalloonTip default False;
    property ValuePasswordChrOnCaps: boolean read FValuePasswordChrOnCaps write FValuePasswordChrOnCaps default True;

//... The usual property declaration of TEdit

    property OnPasswordCapsLocked: TNotifyEvent read FOnPasswordCapsLocked write SetOnPasswordCapsLocked;
    property OnPasswordCapsFreed: TNotifyEvent read FOnPasswordCapsFreed write SetOnPasswordCapsFreed;
  end;


implementation

uses
  Winapi.CommCtrl,
  Winapi.Windows;

{ TNCREdit }

procedure TNCREdit.DoEnter;
begin
  inherited;
  if FBlockCapsBalloonTip then
    begin
      FIsCapsLocked := Odd(GetKeyState(VK_CAPITAL));
      SetOnPasswordCapsEvents;
    end;
end;

procedure TNCREdit.DoExit;
begin
  if FBlockCapsBalloonTip and (FIsCapsLocked) then
    begin
      FIsCapsLocked := False;
      SetOnPasswordCapsEvents;
    end;
  inherited;
end;

procedure TNCREdit.KeyUp(var Key: Word; Shift: TShiftState);
begin
  if Key = VK_CAPITAL then
    FIsCapsLocked := not FIsCapsLocked;
  SetOnPasswordCapsEvents;
  inherited;
end;

procedure TNCREdit.SetOnPasswordCapsEvents;
begin
  if FIsCapsLocked then
    begin
      if Assigned(FOnPasswordCapsLocked) and
         ((self.PasswordChar <> #0) or ( not FValuePasswordChrOnCaps)) then
      begin
      FOnPasswordCapsLocked(Self);
      end;
    end
  else
    begin
      if Assigned(FOnPasswordCapsLocked) and
         ((self.PasswordChar <> #0) or ( not FValuePasswordChrOnCaps)) then
      begin
      FOnPasswordCapsFreed(Self);
      end;
    end;
end;

procedure TNCREdit.SetOnPasswordCapsFreed(const aValue: TNotifyEvent);
begin
  FOnPasswordCapsFreed := aValue;
  FBlockCapsBalloonTip := True;
end;

procedure TNCREdit.SetOnPasswordCapsLocked(const aValue: TNotifyEvent);
begin
  FOnPasswordCapsLocked := aValue;
  FBlockCapsBalloonTip := True;
end;

procedure TNCREdit.WndProc(var Message: TMessage);
begin
  if (Message.Msg = EM_SHOWBALLOONTIP) and FBlockCapsBalloonTip then Exit; 
  inherited;
end;

end.

<小时/>

Kobik 先生编写了一段非常优雅的代码，我认为 PasteBin 不应该被信任托管，因此我决定将其添加到此处。

据我了解，它可以让你处理 TPasswordCapsLockState在 TPasswordEdit 时触发的一个事件处理程序中接收焦点、失去焦点、在焦点上按下 CapsLock 键以及在 PasswordChar 时可选触发已更改。

使用这种方法，我可以使用 OnPasswordCapsLock事件来显示/隐藏我的问题中的图像，而不是强制组件的使用者为每个状态使用两个事件处理程序(顺便说一句，非常聪明并且不易出错)。

也只要 LNeedHandle := FBlockCapsBalloonTip and IsPassword;是 True我在 TPasswordEdit 中添加了另一个功能这是 OnEnter 的处理和OnExit在OnPasswordCapsLock还有，

那么我能说什么，科比克先生我的起首是我的轮胎。

type
  TPasswordCapsLockState = (pcsEnter, pcsExit, pcsKey, pcsSetPasswordChar);

  TPasswordCapsLockEvent = procedure(Sender: TObject;
    Locked: Boolean; State: TPasswordCapsLockState) of object;

  TPasswordEdit = class(TCustomEdit)
  private
    FIsCapsLocked: boolean;
    FBlockCapsBalloonTip: boolean;
    FOnPasswordCapsLock: TPasswordCapsLockEvent;
  protected
    procedure WndProc(var Message: TMessage); override;
    procedure KeyUp(var Key: Word; Shift: TShiftState); override;
    procedure DoEnter; override;
    procedure DoExit; override;
    procedure HandlePasswordCapsLock(State: TPasswordCapsLockState); virtual;
    function GetIsPassword: Boolean; virtual;
  public
    property IsPassword: Boolean read GetIsPassword;
  published
    property BlockCapsBalloonTip: boolean read FBlockCapsBalloonTip write FBlockCapsBalloonTip default False;
//... The usual property declaration of TEdit
    property OnPasswordCapsLock: TPasswordCapsLockEvent read FOnPasswordCapsLock write FOnPasswordCapsLock;
  end;

implementation

function TPasswordEdit.GetIsPassword: Boolean;
begin
  Result := ((PasswordChar <> #0) or
   // Edit control can have ES_PASSWORD style with PasswordChar == #0
   // if it was creaed with ES_PASSWORD style
   (HandleAllocated and (GetWindowLong(Handle, GWL_STYLE) and ES_PASSWORD <> 0)));
end;

procedure TPasswordEdit.HandlePasswordCapsLock;
var
  LNeedHandle: Boolean;
begin
  LNeedHandle := FBlockCapsBalloonTip and IsPassword;
  if LNeedHandle then
  begin
    FIsCapsLocked := Odd(GetKeyState(VK_CAPITAL));
    if Assigned(FOnPasswordCapsLock) then
      FOnPasswordCapsLock(Self, FIsCapsLocked, State);
  end;
end;

procedure TPasswordEdit.DoEnter;
begin
  inherited;
  HandlePasswordCapsLock(pcsEnter);
end;

procedure TPasswordEdit.DoExit;
begin
  inherited;
  HandlePasswordCapsLock(pcsExit);
end;

procedure TPasswordEdit.KeyUp(var Key: Word; Shift: TShiftState);
begin
  inherited;
  if Key = VK_CAPITAL then
    HandlePasswordCapsLock(pcsKey);
end;

procedure TPasswordEdit.WndProc(var Message: TMessage);
begin
  if (Message.Msg = EM_SHOWBALLOONTIP) and FBlockCapsBalloonTip and IsPassword then
    Exit;
  // Optional - if password char was changed
  if (Message.Msg = EM_SETPASSWORDCHAR) and Self.Focused then
    HandlePasswordCapsLock(pcsSetPasswordChar);
  inherited;
end;