使用CreateFrm函数需要先声明哪个类?

Question

如题

Answer 1

已经申明了forms单元啊，怎么说这个函数没定义
unit Main;interfaceuses
  Windows, Messages, SysUtils,Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls, JvExControls, JvComponent, JvNavigationPane,
  JvGradientHeaderPanel, JvSpeedButton;type
  TFrm_Main = class(TForm)
    Panel1: TPanel;
    Label1: TLabel;
    Label3: TLabel;
    Button3: TJvSpeedButton;
    Button5: TJvSpeedButton;
    Button6: TJvSpeedButton;
    Button7: TJvSpeedButton;
    JvGradientHeaderPanel1: TJvGradientHeaderPanel;
    JvNavPanelHeader1: TJvNavPanelHeader;
    JvSpeedButton1: TJvSpeedButton;
    JvGradientHeaderPanel3: TJvGradientHeaderPanel;
    procedure btn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Frm_Main: TFrm_Main;implementationuses Client_unit;{$R *.dfm}procedure TFrm_Main.btn1Click(Sender: TObject);
begin
  CreateFrm(TFrm_client,Frm_client);
  try
    Frm_client.ShowModal;
  finally
    FreeAndNil(Frm_client);
  end;end;end.

Answer 2

要这么写
Application.CreateForm(TFrm_client, Frm_client);
或者
Frm_client:= TFrm_client.Create(self);