procedure TForm1.Button2Click(Sender: TObject);
var
  vFS: TFileStream;
  A1: Integer;
begin
  A1 := $07EB;                     //要写入的机器码
  ShowMessage(IntToStr(A1));       //变成了10进制的啦
  vFS := TFileStream.Create(sEdit1.Text, fmOpenReadWrite);
  try
    vFS.Position := $843;        //要写入的FOA(文件偏移地址)即在x64dbg中直接复制得到的那个无需转换！
    vFS.WriteBuffer(A1, Length(E2.Text) div 2);
  finally
    FreeAndNil(vFS);
  end;
end;

procedure TForm1.cc1Click(Sender: TObject);
var
  vFS: TFileStream;
  a: TBytes;
begin
  vFS := TFileStream.Create(sEdit1.text, fmOpenReadWrite);
  try
    vFS.Position := $843; //后面这个赋值E1不会报错
    SetLength(a, Length(E2.Text) div 2);      //后面是写入的长度
    a[0] := $EB;          //后面这里转换成字节数组不会
    a[1] := $07;
    vFS.WriteBuffer(a[0], Length(a));         //a[0]指向首地址
  finally
    FreeAndNil(vFS);
  end;
end;

{好友巧妙的用了一个自定义函数完成转换！
不然直接调用就出错了！
}
function HexToInt(Value: string): Integer;
begin
  result := StrToInt('$' + Value);
end;


procedure TForm1.NewClick(Sender: TObject);
var
  vFS: TFileStream;
  A1: Integer;
begin
  A1 := HexToInt(E2.Text);            //要写入的机器码
//  ShowMessage(IntToStr(A1));       //变成了10进制的啦
  vFS := TFileStream.Create(sEdit1.Text, fmOpenReadWrite);
  try
    vFS.Position := HexToInt(E1.Text);        //要写入的FOA(文件偏移地址)即在x64dbg中直接复制得到的那个无需转换！
    vFS.WriteBuffer(A1, Length(E2.Text) div 2);
  finally
    FreeAndNil(vFS);
  end;
end;

procedure TForm1.sdsdClick(Sender: TObject);
var
  buf: array[0..100] of byte;
  str: string;
begin
  str := '07EB';
  Move(str[1], buf[0], 32);
  ShowMessageFmt('$%.2d, $%.2d, $%.2d, $%.2d', [buf[3], buf[2], buf[1], buf[0]]);
end;