4、  定义函数类型

        在调用DLL的函数之前，我们要在TC中使用DefineProc方法为它定义函数类型，告诉TC函数名称、参数和结果类型。例如下面脚本定义了DrawTextExA函数类型：

  // Registers the function type in TestComplete
  Def_DLL.DefineProc('DrawTextExA',   // function name
                    vt_i4,   // device context
                    vt_lpstr,   // pointer to the string to be drawn
                    vt_i4,   // the string length
                    Def_Rect,   // pointer to the RECT structure
                    vt_i4,   // additional drawing settings
                    Def_DrawTextParams,   // pointer to DRAWTEXTPARAMS
                    vt_i4);   // result type

5、  为结构填充数据

        在使用前面创建的RECT类型变量之前，应该为其填充数据：

  r := DLL.New('RECT');

  r.left := 50;
  r.top := 50;
  r.right := 350;
  r.bottom := 100;

6、  指定string参数的值

        DrawTextEx方法的第二个参数是指定在屏幕上画出来的某个字符串，应该按下面方法准备这段字符串：

LpStr:=DLL.New(‘LPSTR’,256)

LpStr.Text:=’My text’;

7、  把DLL加载到内存

        使用DLL.Load方法加载指定的DLL，例如：

Lib:=DLL.Load(‘C:\Windows\System32\USER32.DLL’,’USER32’);

        对于系统DLL，例如上面的USER32.DLL，我们可以忽略第一个参数，直接使用：

Lib:=DLL.Load(‘USER32’);

8、  调用函数

        现在，我们可以调用DLL的函数了，例如，以下脚本调用DrawTextExA方法：

i := Lib.DrawTextEx(dc, LpStr, Length(LpStr.Text), r,

  DT_PATH_ELLIPSIS, dtp);

        完整的调用USER32.DLL的DrawTextEx函数的脚本如下：

procedure CallRoutineFromDLL;
const
  DT_PATH_ELLIPSIS = $4000;
var
  p, w, s : OleVariant;
  Def_DrawTextParams, Def_Rect, Def_DLL, Lib : OleVariant;
  dtp, LpStr, r, dc, i : OleVariant;
begin
 
 // Text to draw
  s := 'My string: C:\Program Files\Files.txt';
 
  // Defines the dll type
  Def_DLL := DLL.DefineDLL('USER32');
 
 // Registers the DRAWTEXTPARAMS type in TestComplete
  Def_DrawTextParams := DLL.DefineType('DRAWTEXTPARAMS',
                                        vt_i4, 'cbSize',
                                        vt_i4, 'iTabLength',
                                        vt_i4, 'iLeftMargin',
                                        vt_i4, 'iRightMargin',
                                        vt_i4, 'uiLengthDrawn');
 
  // Registers the RECT type in TestComplete
  Def_Rect := DLL.DefineType('RECT',
                                 vt_i4, 'left',
                                 vt_i4, 'top',
                                 vt_i4, 'right',
                                 vt_i4, 'bottom');
 
  // Registers the function type in TestComplete
  Def_DLL.DefineProc('DrawTextExA',   // function name
                    vt_i4,   // device context
                    vt_lpstr,   // pointer to the string to be drawn
                    vt_i4,   // the string length
                    Def_Rect,   // pointer to the RECT structure
                    vt_i4,   // additional drawing settings
                    Def_DrawTextParams,   // pointer to DRAWTEXTPARAMS
                    vt_i4);   // result type
 
  // Creates an alias for DrawTextExA
  Def_DLL.DefineAlias('DrawTextEx', 'DrawTextExA');
 
  // Registers the types of the GetDC
  // and ReleaseDC routines. They will
  // be used to work with the device context
  Def_DLL.DefineProc('GetDC', vt_i4, vt_i4);
  Def_DLL.DefineProc('ReleaseDC', vt_i4, vt_i4, vt_i4);
 
  // Creates the RECT structure and fills it with data
  r := DLL.New('RECT');
  r.left := 50;
  r.top := 50;
  r.right := 350;
  r.bottom := 100;
 
  // Creates the DRAWTEXTPARAMS structure and fills it with data
  dtp := DLL.New('DRAWTEXTPARAMS');
  dtp.cbSize := 20; // Structure size
  dtp.iTabLength := 2;
  dtp.iLeftMargin := 2;
  dtp.iRightMargin := 2;
  dtp.uiLengthDrawn := 0;
 
  // Creates the string parameter
  LpStr := DLL.New('LPSTR', 256);
  LpStr.Text := s;
 
  // Loads the dll
  // We use such a brief notation,
  // because USER32.DLL is a system library and
  // the dll type name (USER32) coincides with
  // the dll file name
  Lib := DLL.Load('USER32');
 
  // Gets the device context for drawing
  dc := Lib.GetDC(0);
  // Calls the function from the DLL
  i := Lib.DrawTextEx(dc, LpStr, Length(LpStr.Text), r,
  DT_PATH_ELLIPSIS, dtp);
  // Releases the device context
  Lib.ReleaseDC(0, dc);
end;