请帮忙看一下,我的这个重载constructor create为何不成功?

Question

目的是给TForm_SDALL类加一个新属性TblName:String,调用动态生成实例并给TblName赋值.//(1)单元文件内容
unit SDALL;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, StdCtrls, Buttons, Grids, DBGridEh;type
  TForm_SDALL = class(TForm)
  public
    constructor create;overload;
    TblName:String;
    constructor create(const str:String);overload;
  end;var
  Form_SDALL: TForm_SDALL;implementation
uses MAINMENU;{$R *.dfm}PROCEDURE TForm_SDALL.create(str:String);
begin
  inherited Create;
  TblName:=str;
end;end.
//(2)在另一个地方引用时出错
var
  myForm:TForm;
begin
   myForm:=TForm_SDALL.Create('SSS'); //这句编译时出错,说 Incompatible types: 'TComponent' and 'String'
end;

Answer 1

TForm_SDALL = class(TForm)
  public
    constructor create(str:String);//这里改成这样
    TblName:String;
    constructor create(const str:String);overload;
  end;

Answer 2

constructor create(AOwner:TComponent;const str:String);reintroduce;PROCEDURE TForm_SDALL.create(AOwner:TComponent;str:String);
begin
  inherited Create(AOwner);
  TblName:=str;
end;

Answer 3

constructor create(AOwner:TComponent;const str:String);reintroduce;constructor TForm_SDALL.create(AOwner:TComponent;str:String);
begin
  inherited Create(AOwner);
  TblName:=str;
end;

Answer 4

谢谢二位回答!TO: bee2518(迷茫ing)
按您的做了,问题依旧.TO: tonylk(=www.tonixsoft.com=) 
按您的做了,调用也得跟着改成
TForm_SDALL.Create(nil,'SSS'); 或者
TForm_SDALL.Create(application,'SSS'); 
都会出现 [Error]: Too many actual parameters .看起来,好象它还是在调用重载前的默认create,这个是只有一个参数的,而参数类型就为TComponent.

Answer 5

TO:  tonylk(=www.tonixsoft.com=) 
按您的来,调用
TForm_SDALL.Create(application,'SSS'); 
也会出现 [Error]: Too many actual parameters

Answer 6

constructor create(AOwner: TComponent; const str:String); reintroduce;PROCEDURE TForm_SDALL.create(AOwner: TComponent; const str:String);
begin
  inherited Create(AOwner);
  TblName:=str;
end;

Answer 7

unit Unit2;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;type
  TForm2 = class(TForm)
  private
    { Private declarations }
  public
    TblName:String;
    constructor create; reintroduce;overload;
    constructor create(const str:String);overload;
    { Public declarations }
  end;var
  Form2: TForm2;implementation{$R *.dfm}{ TForm2 }constructor TForm2.create;
begin
  inherited Create(Application);
end;constructor TForm2.create(const str: String);
begin
  inherited Create(Application);
  TblName:=str;
end;end.

Answer 8

注意，你的tblname 位置不对需要提到方法之前

Answer 9

最好你再定义一个FAowner属性将上面的
  inherited Create(Application);
改为
  inherited Create(FAowner);
这样就和原来完全兼容了

Answer 10

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;type
  TForm1 = class(TForm)
  private
    { Private declarations }
  public
    { Public declarations }
    Constructor Create(Text:string); reintroduce ; overload;
  end;var
  Form1: TForm1;implementation{$R *.dfm}
Constructor TForm1.Create(Text:string);
begin
  inherited Create(Application);
  showmessage(text);
end;