在许多网站上,我可以看到带有灰色提示的文本框。提示将告诉用户应该输入什么,每当用户尝试输入任何内容时,提示就会消失。
下面是它的一个示例:
我只是想知道如何在Windows桌面应用程序中实现这种功能。我正在使用Delphi XE3,可以用TTextBox实现这样的功能吗?还是有这样的VCL组件可用?
答案 0 :(得分:4)
这里是适用于Windows XP的实现(以及Windows 7和8.1,尚未在Windows 10上对其进行测试)。注意:我主要在Windows XP和8.1以及Delphi 2007和XE2中使用它。可能有一些我尚未见过的错误。
它可能也不是最优雅的解决方案,但它可以工作并且易于理解。
先决条件:Delphi Custom Containers Pack
只需将以下内容保存到u_dzCueEdit.dfm和u_dzCueEdit.pas,使用它创建一个运行时程序包,并使用Register过程创建一个相应的设计时程序包并安装它。
dfm文件:
object dzCueEdit: TdzCueEdit
Left = 0
Top = 0
Width = 258
Height = 21
TabOrder = 0
OnResize = BoxResize
object ed_Cue: TEdit
Left = 1
Top = 1
Width = 256
Height = 19
Align = alClient
TabOrder = 0
OnChange = ed_CueChange
OnClick = ed_CueClick
OnEnter = ed_CueEnter
OnExit = ed_CueExit
end
object p_Cue: TPanel
Left = 64
Top = 0
Width = 242
Height = 21
BevelOuter = bvNone
Color = clMoneyGreen
ParentBackground = False
TabOrder = 1
OnClick = p_CueClick
OnEnter = p_CueEnter
object l_Cue: TLabel
AlignWithMargins = True
Left = 88
Top = 0
Width = 93
Height = 13
Margins.Left = 1
Margins.Top = 1
Margins.Right = 1
Margins.Bottom = 1
Caption = 'Cue text goes here'
Font.Charset = DEFAULT_CHARSET
Font.Color = clGray
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
ParentFont = False
OnClick = l_CueClick
end
end
end
pas文件: 单位c_dzCueEdit;
interface
uses
Windows,
Messages,
SysUtils,
Classes,
Graphics,
Controls,
Forms,
Dialogs,
ExtCtrls,
StdCtrls,
ccBoxes;
type
TdzCueEdit = class(TBox)
p_Cue: TPanel;
l_Cue: TLabel;
procedure ed_CueClick(Sender: TObject);
procedure l_CueClick(Sender: TObject);
published
ed_Cue: TEdit;
procedure p_CueEnter(Sender: TObject);
procedure p_CueClick(Sender: TObject);
procedure ed_CueChange(Sender: TObject);
procedure ed_CueEnter(Sender: TObject);
procedure ed_CueExit(Sender: TObject);
procedure BoxResize(Sender: TObject);
private
procedure CheckCueBanner;
function GetCue: string;
function GetText: string;
procedure SetCue(const _Value: string);
procedure SetText(const _Value: string);
protected
public
constructor Create(_Owner: TComponent); override;
published
property Text: string read GetText write SetText;
property Cue: string read GetCue write SetCue;
end;
implementation
{$R *.DFM}
{ TdzCueEdit }
constructor TdzCueEdit.Create(_Owner: TComponent);
begin
inherited;
BevelOuter := bvNone;
l_Cue.Align := alClient;
p_Cue.Color := ed_Cue.Color;
end;
procedure TdzCueEdit.BoxResize(Sender: TObject);
var
Rect: TRect;
begin
Rect := ed_Cue.ClientRect;
// p_Cue.SetBounds(Rect.Left, Rect.Top, Rect.Right - Rect.Left, Rect.Bottom - Rect.Top);
p_Cue.SetBounds(Rect.Left + 4, Rect.Top + 3, Rect.Right - Rect.Left - 2, Rect.Bottom - Rect.Top - 2);
end;
procedure TdzCueEdit.CheckCueBanner;
begin
if ed_Cue.Text <> '' then
p_Cue.Visible := False
else begin
// if ed_Cue.Focused then
// p_Cue.Visible := False
// else
p_Cue.Visible := True;
end;
end;
procedure TdzCueEdit.ed_CueChange(Sender: TObject);
begin
CheckCueBanner;
end;
procedure TdzCueEdit.ed_CueClick(Sender: TObject);
begin
CheckCueBanner;
end;
procedure TdzCueEdit.ed_CueEnter(Sender: TObject);
begin
CheckCueBanner;
end;
procedure TdzCueEdit.ed_CueExit(Sender: TObject);
begin
CheckCueBanner;
end;
function TdzCueEdit.GetCue: string;
begin
Result := l_Cue.Caption;
end;
procedure TdzCueEdit.SetCue(const _Value: string);
begin
l_Cue.Caption := _Value;
end;
function TdzCueEdit.GetText: string;
begin
Result := ed_Cue.Text;
end;
procedure TdzCueEdit.l_CueClick(Sender: TObject);
begin
ed_Cue.SetFocus;
CheckCueBanner;
end;
procedure TdzCueEdit.SetText(const _Value: string);
begin
ed_Cue.Text := _Value;
end;
procedure TdzCueEdit.p_CueClick(Sender: TObject);
begin
ed_Cue.SetFocus;
CheckCueBanner;
end;
procedure TdzCueEdit.p_CueEnter(Sender: TObject);
begin
ed_Cue.SetFocus;
CheckCueBanner;
end;
end.