请问如何动态修改exe文件的图标

Question

unit ICOEXE;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ComCtrls,shellapi;type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Label2: TLabel;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    OpenDialog1: TOpenDialog;
    OpenDialog2: TOpenDialog;
    StatusBar1: TStatusBar;
    procedure Button2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button2Click(Sender: TObject);
begin
    Close;
end;procedure TForm1.Button1Click(Sender: TObject);
const
        readlen=10;  //每次读取字节数，可改变
        icolen=766;//32*32图标长度,根据研究前126为图标头,后640为图标数据
var
        i,j,itemp,nPos:int64;// nPos为目的图标在目的文件的位置
        ci,cj:array[0..readlen-1] of char;
        SourceFile,DestFile:String;//如果要把记事本图标换成瑞星杀毒软件图标
        bOK:boolean;//则SourceFile='C:\windows\notepad.exe',DestFile:='C:\Progra
m Files\rising\rav\ravmon.exe'
        SourceIcon,DestIcon:TIcon;
        SIconStream,s,sDest:TMemoryStream;
begin
        bOK:=false;
        if OpenDialog1.Execute then
            SourceFile:=OpenDialog1.FileName
        else
            exit;
        if  AnsiUpperCase(ExtractFileExt(SourceFile))<>'.EXE' then
        begin
            ShowMessage(AnsiUpperCase(ExtractFileExt(SourceFile)));
            exit;
        end;
        Edit1.Text:=SourceFile;
        if OpenDialog2.Execute then
            DestFile:=OpenDialog2.FileName
        else
            exit;
        if  AnsiUpperCase(ExtractFileExt(DestFile))<>'.EXE' then
            exit;
        Edit2.Text:=DestFile;
        SourceIcon:=TIcon.Create;
        case ExtractIcon(handle,PChar(SourceFile),UINT(-1)) of
            0:begin ShowMessage('源程序没有图标');exit;end;
            1:;
            else ShowMessage('源程序有多个图标,本程序选择第一个图标');
        end;
        SourceIcon.Handle:=ExtractIcon(handle,PChar(SourceFile),0);//选择第一个图
标
        DestIcon:=TIcon.Create;//选择第N个图标为 ExtractIcon(handle,PChar(Source
File),N-1)
        case ExtractIcon(handle,PChar(DestFile),UINT(-1)) of
            0:begin ShowMessage('目的程序没有图标');exit;end;
            1:;
            else ShowMessage('目的程序有多个图标,本程序选择第一个图标替换');
        end;
        DestIcon.Handle:=ExtractIcon(handle,PChar(DestFile),0);//选择第一个图标
        SIconStream:=TMemoryStream.Create;
        DestIcon.SaveToStream(sIconStream);
        if sIconStream.size<>icolen then
            ShowMessage('SIcon.size<>icolen');
        SDest:=TMemoryStream.Create;
        sDest.LoadFromFile(DestFile);
        i:=0;j:=0;   //以下程序查找目的图标在目的程序中的位置
        while  i< sDest.size do
        begin
               itemp:=i;
               j:=126;
{               repeat
                    SDest.Position:=i;
                    sDest.read(ci,Readlen);
                    SiconStream.Position:=j;
                    SIconStream.Read(cj,Readlen);
                    i:=i+Readlen;
                    j:=j+Readlen;
               until (String(ci)=String(cj)) and (i<sDest.size) and (j<icolen);
}                       ci:='';cj:='';
                        while (String(ci)=String(cj)) and (i<SDest.size) and (j<
icolen) do
                        begin
                                i:=i+readlen;
                                j:=j+readlen;
                                SDest.Position:=i;
                                SDest.read(ci,readlen);
                                SiconStream.Position:=j;
                                SiconStream.Read(cj,readlen);
                        end;
               if j<icolen then
                    i:=itemp+1  //没找到
               else
               begin
                   nPos:=itemp;  //找到
                   bOK:=true;
                   break;
               end;
        end;
        if bOK=false then
           exit;//目标文件二进制码中未找到图标
        SIconStream.Clear;//将源程序图标存入
        SourceIcon.SaveToStream(SIconStream);        SIconStream.position:=126;
        s:=TMemoryStream.Create;        sDest.Position:=0;
        s.CopyFrom(sDest,nPos);//将目的程序图标前数据拷入
        s.CopyFrom(SIconStream,640); //将源程序图标拷入
        if sDest.size>sDest.Position+640 then //将目的程序剩余数据拷入
        begin
             sDest.Position:=sDest.Position+640;
             s.CopyFrom(sDest,sDest.Size-sDest.Position);
        end;
        s.SaveToFile(Extractfilepath(application.exename)+'Result.exe');
        SourceIcon.Free;DestIcon.Free; //改造好的程序存放在本目录Result.exe文件中
        SIconStream.Free;s.Free;sDest.Free;
        ShowMessage(Extractfilepath(application.exename)+'Result.exe');
end;
//以上程序可以将目的程序的第一个图标换成源程序的第一个图标,经实证很多程序有二个
//或更多图标,转换原理相似,不在陈述
end.