Delphi调用WinAPI: 输入光标相关的函数[4]

本例效果图:

代码文件:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs;
type
　TForm1 = class(TForm)
　　procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
　　　Shift: TShiftState; X, Y: Integer);
　　procedure FormKeyPress(Sender: TObject; var Key: Char);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
var
　str: string;
　x1,y1: Integer;
procedure TForm1.FormKeyPress(Sender: TObject; var Key: Char);
var
　x2: Integer;
begin
　HideCaret(Handle);
　Repaint;
　if Key = #8 then
　begin
　　if Length(str) > 0 then
　　SetLength(str, Length(str) - 1);
　end else str := str + Key;
　Text := str;
　Canvas.TextOut(x1, y1, str);
　x2 := x1 + Canvas.TextWidth(str);
　SetCaretPos(x2, y1);
　ShowCaret(Handle);
end;
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
　Shift: TShiftState; X, Y: Integer);
begin
　str := '';
　DestroyCaret;
　CreateCaret(Handle, 0, 0, Canvas.TextHeight('A'));
　SetCaretPos(X,Y);
　ShowCaret(Handle);
　x1 := X;
　y1 := Y;
end;
end.

窗体文件:

object Form1: TForm1
　Left = 0
　Top = 0
　Caption = 'Form1'
　ClientHeight = 206
　ClientWidth = 339
　Color = clBtnFace
　Font.Charset = DEFAULT_CHARSET
　Font.Color = clWindowText
　Font.Height = -11
　Font.Name = 'Tahoma'
　Font.Style = []
　OldCreateOrder = False
　OnKeyPress = FormKeyPress
　OnMouseDown = FormMouseDown
　PixelsPerInch = 96
　TextHeight = 13
end