請問: type Test = record X, Y: Single; end; Test可以用Pointer方式傳輸嘛.? 如何使用? 謝謝

可以的

type
  Test = record
     X, Y: Single;
  end;
  
  pTest = ^Test;    使用時
var
  ptExample:pTest;
begin
  New(ptExample);
  ptExample^.X:=100;
  ptExample^.Y:=100;
  testProcedure(ptExample);
   ...
  dispose(ptExample); 
end;    Procedure testProcedure(ptEx:ptTest);
var
  x,y:Single;
begin
  x:=ptEx^.X;
  y:=ptEx^.Y;
  ptEx^.X:=0;
  ptEx^.Y:=0;
end;

發表人 - chris_shieh 於 2004/12/17 11:57:28

你好：
  補充 chris_shieh 的回答, 也可以這樣傳遞    var
  Example : Test;
begin
  Example.X:=100;
  Example.Y:=100;
  testProcedure(@Example); // @ 是傳回變數的指標
end;        

如果是函式是這樣請問如何傳 Procedure testProcedure(userdata:Point); thk

Procedure testProcedure(userdata:Point); 我想這應該要看你Point 型態的定義為何才能決定吧

Point 也是Pointer型態嗎
那就是
var
  originPt:Point;
begin
  new(originPt);
  //參考我前面的post 可以指定 originPt的值
  testProcedure(originPt);
  ...
  ...
  dispose(originPt);
end;    如果你的Point 型態是跟 TPoint 有關的話 (應該不是吧)
那就是
>        發表人 - 
        

原函式為 function test(UserData: Pointer = nil): Cardinal; 那UserData可傳那種類資料, type類型的可以嗎 type Test = record X, Y: Single; end; 謝謝

unit Unit1;    interface    uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;    type
  Test = record
    X, Y: Single;
  end;
  pTest = ^Test;      TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    ptEx:pTest;
    function test(UserData: Pointer = nil): Cardinal;
    { Public declarations }
  end;    var
  Form1: TForm1;    implementation    {$R *.dfm}    function TForm1.test(UserData: Pointer = nil): Cardinal;
var
  ptLocal:pTest;
begin
  ptLocal:=pTest(UserData); //Type casting to pTest
  Showmessage(FloatToStr(ptLocal^.X));
  Showmessage(FloatToStr(ptLocal^.Y));
  ptLocal.X:=ptLocal.X*10; //update value
  ptLocal.Y:=ptLocal.Y*10; //update value
end;    procedure TForm1.FormCreate(Sender: TObject);
begin
  new(ptEx);
  ptEx.X:=10;
  ptEx.Y:=20;
  test(ptEx); 
  Showmessage(FloatToStr(ptEx^.X)); //show updated value
  Showmessage(FloatToStr(ptEx^.Y)); //show updated value
  dispose(ptEx);
end;    end.    

很抱歉,表達有點錯誤 1.我是用由別人開發的物件,故無法修改函式內的程式 2.原件動作步驟如下 function test(UserData: Pointer = nil): Cardinal; 當下了該行函數後,在某狀態會觸發事件,而是件內包含以下資料 TTransactionInfo = record ID: Cardinal; UserData: Pointer; end; 而UserData會引用test傳入Pointer 該項解說是 UserData is a pointer to user-defined data that was supplied by the application to a previous call to one of the transaction initiation methods. 那UserData: Pointer;可以傳type嗎. 謝謝 謝謝

UserData is a pointer to user-defined data that was supplied by the application to a previous call to one of the transaction initiation methods. 所以 UserData 應該是您呼叫 transaction initiation methods 而可以得到的吧 function test 還是要傳Pointer , 不管是typed or untyped 我想test function 內應該自己會作處理 根據Delphi Online Help: Addr function ...... The result of Addr is of the predefined type Pointer, which means that it is assignment-compatible with all pointer types but can't be dereferenced directly without a typecast. 不過我想你應該要先瞭解test function所需要的 UserData 真正的型態定義才能給一個正確的UserData, 也才能正確宣告UserData

var
  UserData:Pointer;
begin
  UserData:=Get_From_TransInit_Method; //如果傳回的也是Pointer
  test(UserData);
end;

發表人 - chris_shieh 於 2004/12/20 17:36:48