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The author:(作者)aaa
published in(发表于) 2014/7/19 0:11:47
delphi映像内存发送端

映像内存发送端

发送端利用CreateFileMapping 函数建立内存映像文件，并用MapViewOfFile 函数将映像文件映射到本进行中，并利用PostMessage 发送信息，具体步骤及方法如下。

（1）新建一个项目。将窗体的Caption 设置为“映像内存发送端”。在窗体上添加一个Caption 属性为“发送数据”的Button 组件。

（2）程序源代码如下：

unit Unit1;

interface

Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,

StdCtrls;

const

WM_DATA = WM_USER + 1024;

type

PShareMem = ^TShareMem;

TShareMem = record

Data: array[0..255] of char;

end;

TForm1 = class(TForm)

Button1: TButton;

procedure Button1Click(Sender: TObject);

procedure FormDestroy(Sender: TObject);

procedure FormCreate(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

var

Form1: TForm1;

PShare: PShareMem;

implementation

{$R *.DFM}

var

HMapping: THandle;

HMapMutex: THandle;

const

MAPFILESIZE = 1000;

REQUEST_TIMEOUT = 1000;

procedure OpenMap; //打开建立共享内存

begin

{创建一个文件映射内核对象}

HMapping := CreateFileMapping(

$FFFFFFFF,

nil,

PAGE_READWRITE,

0,

SizeOf(TShareMem),

pchar(’Map Name’) {映像文件的名字是’Map Name’}

);

if (hMapping = 0) then

begin

ShowMessage(’不能创建内存映射文件’);

Application.Terminate;

exit;

end;

{将映像文件映射到进程的地址空间}

PShare := PShareMem(MapViewOfFile(HMapping, FILE_MAP_ALL_ACCESS, 0, 0, 0));

if PShare = nil then

begin

CloseHandle(HMapping);

ShowMessage(’Can’’t View Memory Map’);

Application.Terminate;

exit;

end;

end;

procedure CloseMap; //关闭共享内存

begin

if PShare <> nil then

{从进程的地址空间中撤消文件数据的映像}

UnMapViewOfFile(PShare);

if HMapping <> 0 then

CloseHandle(HMapping); //关闭映像文件

end;

function LockMap: Boolean; //建立互斥对象

begin

Result := true;

{创建互斥对象}

HMapMutex := CreateMutex(nil, false,

pchar(’MY MUTEX NAME GOES HERE’));

if HMapMutex = 0 then

begin

ShowMessage(’不能创建互斥对象’);

Result := false;

end else begin

if WaitForSingleObject(HMapMutex, REQUEST_TIMEOUT)

= WAIT_FAILED then

begin

ShowMessage(’不能对互斥对象加锁!’);

Result := false;

end;

end;

end;

procedure UnlockMap; //释放互斥对象

begin

ReleaseMutex(HMapMutex);

CloseHandle(HMapMutex);

end;

procedure TForm1.Button1Click(Sender: TObject);

var

str: pchar;

begin

str := pchar(’简单的共享内存的例子’);

CopyMemory(@(pShare^.data), Str, Length(str));

{发送消息表明有数据}

PostMessage(FindWindow(nil, ’映像内存接收端’), WM_DATA, 1, 1)

end;

procedure TForm1.FormDestroy(Sender: TObject);

begin

UnlockMap;

CloseMap;

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

OpenMap;

LockMap;

end;

end.

（3）保存工程为“SendDemo.dpr”。

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