关于Delphi中多线程传递参数的简单问题

没有昵称哦 2013-07-09 09:36:57

unit uThread;



interface



uses

  Classes;



type

  Th = class(TThread)

  private

    { Private declarations }

   

  protected

    procedure Execute; override;

  end;

以上是创建的一个多线程
我在另外一个单元里Unit1有一个函数

function Myfun(username,password:string):boolean

现在要把Myfun放到多线程里执行，怎么传递参数呢？
谁有这样的Demo给一个我，帮我讲解一下，感激不尽！我看到网上说有结构体，因本人才学Delphi没多久，不太懂的，希望大牛们指点迷津！

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sololie 2013-07-26

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property UserName: string read FUserName write GetUserName; property PassWord: string read FPassWord write GetPassWord; 名字都给弄错了，SetUserName、SetPassWord

property UserName: string read FUserName write SetUserName; property PassWord: string read FPassWord write SetPassWord;

mdejtod 2013-07-10

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传递函数指针，以回调的形式调用


type
  TMyFunc = function(username,password:string):boolean;stdcall; 
  Th = class(TThread)  
  private    { Private declarations } 
   FMyFunc : pointer;     
  protected    
    procedure Execute; override; 
  public
    Procedure SetMyFunc(func : pointer); 
  end;
implementation
procedure Th.Execute;
begin
  if assigned(FMyFunc) then TMyFunc(FMyFunc)(username,password);
end;

procedure Th.SetMyFunc(func : pointer); 
begin
  FMyFunc := func;
end;

//在其它地方定义一个函数，比如
function MyFunc(username,password) :boolean;stdcall;
begin
  //
end;

procedure TForm1.btn1Click(Sender: TObject);
 var  myThread: TMyThread;
begin  
  myThread := TMyThread.Create(false);
  myThread.SetMyFunc(@MyFunc); 
end;

sololie 2013-07-09

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function Myfun(FUserName, FPassWord: string): Boolean; 这行上面加个 private: 这个函数没必要也不应该public。另外注意，如果线程中涉及操作UI，就把操作UI的代码放到Synchronize中执行例如：


unit Unit2;

interface

uses
  Classes;

type
  TMyThread = class(TThread)
  private
    FUserName: string;
    FPassWord: string;
    FFlag: Boolean;
    procedure GetUserName(const Value: string);
    procedure GetPassWord(const Value: string);

    procedure Myfun; // 原本的参数传递交由 TMyThread的实例赋值完成
  protected
    procedure Execute; override;
  public
    property UserName: string read FUserName write GetUserName;
    property PassWord: string read FPassWord write GetPassWord;
    property MyFunRetVal: Boolean read FFlag default False;
    constructor Create(b: Boolean = True);
  end;

implementation

procedure TMyThread.Myfun;
begin
  // 假设这里做了操作UI的工作
  FFlag := True;
end;

constructor TMyThread.Create(b: Boolean = True);
begin
  inherited Create(b);
  Self.FreeOnTerminate := True;
end;

procedure TMyThread.Execute;
begin
  // 让操作UI的代码放回主线程中执行已保证同步
  Synchronize(Myfun);
end;

procedure TMyThread.GetPassWord(const Value: string);
begin
  FPassWord := Value;
end;

procedure TMyThread.GetUserName(const Value: string);
begin
  FUserName := Value;
end;

end.

sololie 2013-07-09

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// 线程类
unit Unit2;

interface

uses
  Classes;

type
  TMyThread = class(TThread)
  private
    FUserName: string;
    FPassWord: string;
    FFlag: Boolean;
    procedure GetUserName(const Value: string);
    procedure GetPassWord(const Value: string);
    { Private declarations }
  protected
    procedure Execute; override;
  public
    property UserName: string read FUserName write GetUserName;
    property PassWord: string read FPassWord write GetPassWord;
    property MyFunRetVal: Boolean read FFlag default False;
    function Myfun(FUserName, FPassWord: string): Boolean;
    constructor Create(b: Boolean = True);
  end;

implementation

function TMyThread.Myfun(FUserName, FPassWord: string): Boolean;
begin
  Result := True; // 简单起见让它固定为True
end;

constructor TMyThread.Create(b: Boolean = True);
begin
  inherited Create(b);
  Self.FreeOnTerminate := True;
end;

procedure TMyThread.Execute;
begin
  FFlag := Myfun(FUserName, FPassWord);
end;

procedure TMyThread.GetPassWord(const Value: string);
begin
  FPassWord := Value;
end;

procedure TMyThread.GetUserName(const Value: string);
begin
  FUserName := Value;
end;

end.


// 调用单元
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    btn1: TButton;
    procedure btn1Click(Sender: TObject);
  private
  public
    procedure MyOnTerminate(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses Unit2; // 线程类定义在unit2单元

var
  retVal: Boolean; // 线程"返回值"

procedure TForm1.btn1Click(Sender: TObject);
var
  myThread: TMyThread;
begin
  myThread := TMyThread.Create; // 创建线程并挂起
  myThread.UserName := 'sololie'; // 传参
  myThread.PassWord := '撸过更健康';
  myThread.OnTerminate := MyOnTerminate; // 线程结束的回调函数
  myThread.Resume; // 开始执行线程
end;

procedure TForm1.MyOnTerminate(Sender: TObject);
begin
  retVal := (Sender as TMyThread).MyFunRetVal;
  if retVal then
    ShowMessage('线程执行函数返回 True')
  else
    ShowMessage('线程执行函数返回 False');
end;

end.

没有昵称哦 2013-07-09