1. Calling C++ DLLs from VC++ -- with Win32 Dynamic-Link Library Copyright (c) 2006 NCNU Lab 202 All Rights Reserved

2. Files Required To Use A DLL Programmer : Normal User : .dll

3. Loading Method Loading DLL Implicitly  A DLL that exports some symbols. Loading DLL Explicitly  Using ".def " file. Calling GUI DLL  Using MFC DLL  Call by C# Application  Call by MFC Application Return Input DLL Call DLL

4. Method One Using Exported Symbols

5. Initial Dll Project – step 1

6. Initial Dll Project – step 2

7. Initial Dll Project – step 3

8. Initial Dll Project – step 4

9. Initial Define #pragma message("automatic link to MyDll.lib") #pragma comment(lib, "MyDll.lib")  Ensure when a project include the DLL’s header file, it will automatically link to the DLL’s Lib file.

10. Initial Dll Project – step 5

11. Understanding DllMain() BOOL APIENTRY DllMain ( HMODULE hModule,//Identify DLL DWORD ul_reason_for_call,//Why Call ?? LPVOID lpReserved//pointer )

12. Edit MyDll.h extern MYDLL_API float num_01 ; extern MYDLL_API float num_02 ; class MYDLL_API Plus { public: Plus(void) ;//Constructor float static myplus(float m, float n); //function float static dimension_1(float m, float n) ; //function };

13. Edit MyDll.cpp MYDLL_API float num_01 = 0 ;//set default vale MYDLL_API float num_02 = 0 ;//set default vale float Plus::myplus(float n, float m) { return (num_01 + num_02) ; } float Plus::dimension_1(float m, float n) { return ((num_01 + num_02) + (num_01 + num_02)) ; } Compile project “MyDLL" to get “MyDll.dll" & "method_01.lib". It will be under "..\debug "

14. Initial Console Project – step 1

15. Initial Console Project – step 2

16. Initial Console Project – step 3

17. Initial Console Project – step 4

18. Initial Console Project – step 5

19. Initial Console Project – step 6

20. Edit AppConsole.cpp - 01 float num_a = num_01 ; float num_b = num_02 ; cout << "Default Value : " << endl ; cout << "num_a = " << num_a << ", num_b = “<< num_b << endl ;

21. Edit AppConsole.cpp - 02 cout << "Keyin New Value : " << endl ; cout > num_01 ; cout > num_02 ; cout << "Update Value : " << endl ; cout << "num_01 = " << num_01 << ", num_02 = " << num_02 << endl ;

22. Edit AppConsole.cpp - 03 doplus = Plus::myplus(num_01, num_02) ; dimension_01 = Plus::dimension_1(num_01, num_02) ; cout << num_01 << " + " << num_02 << " = " << doplus << endl ; cout << "Result dimension_01 = " << dimension_01 << endl ;

23. Initial MFC Project – step 1

24. Initial MFC Project – step 2

25. Initial MFC Project – step 3

26. Initial MFC Project – step 4

27. Initial MFC Project – step 5

28. Initial MFC Project – step 6

29. Insert New Item

30. Add Member Variables - 1

31. Add Member Variables - 2

32. Add Member Variables - 3

33. Edit AppMFCDlg.cpp void CAppMFCDlg::OnBnClickedButton1() { CString mystr_a = string_a ; CString mystr_b = string_b ; CString mystr_c = string_c ; m_static.SetWindowText(mystr_a) ; m_edit.SetWindowText(mystr_b) ; m_button.SetWindowText(mystr_c) ; }

34. After Executing

35. Method Two Using ".def " File

36. Initial ExplicitDLL Project – step 1

37. Initial ExplicitDLL Project – step 2

38. Initial ExplicitDLL Project – step 3

39. Initial ExplicitDLL Project – step 4

40. Initial ExplicitDLL Project – step 5

41. Initial ExplicitDLL Project – step 6

42. Edit count.h

43. Edit count.cpp

44. Compile project "ExplicitDLL" to get “ExplicitDLL.dll" & "ExplicitDLL.lib". It will be under "..\debug " Edit count.def

45. Initial ExplicitDLL2 Project Follow page35 ~ page 42 to make ExplicitDLL2 After compile, you will get ExplicitDLL2.dll and ExplicitDLL2.lib

46. Initial DllMFC Project – step 1

47. Initial DllMFC Project – step 2

48. Initial DllMFC Project – step 3

49. Initial DllMFC Project – step 4

50. Add Member Variables - 1

51. Add Member Variables - 2

52. Edit DllMFCDlg.cpp - 1 typedef double (*LPGETNUMBER)(double Nbr) ;//define type HINSTANCE hDLL = NULL ;//default value LPGETNUMBER lpGetNumber ;//set pointer

53. Edit DllMFCDlg.cpp - 2 hDLL = AfxLoadLibrary("ExplicitDLL");//load DLL if( hDLL == NULL ) { AfxMessageBox("Can't load ExplicitDLL");//show message m_button1.ShowWindow(SW_HIDE) ;//hide button1 } else { lpGetNumber = (LPGETNUMBER)GetProcAddress(hDLL, "GetNumber"); }

54. Edit DllMFCDlg.cpp - 3 void CDllMFCDlg::OnBnClickedGetNumberBtn1() { double Number, GetNbr; UpdateData(); Number = atof(m_Number); GetNbr = lpGetNumber(Number); m_GetNumber.Format("%.2f", GetNbr); UpdateData(FALSE); }

55. After Executing – delete ExplicitDLL2.dll

56. After Executing – calling ExplicitDLL.dll

57. After Executing – calling ExplicitDLL2.dll

58. Calling GUI DLL

59. Initial MyDLL Project – step 1

60. Initial MyDLL Project – step 2

61. Initial MyDLL Project – step 3

62. Initial MyDLL Project – step 4

63. Add Dialog Class

64. Edit IDD_MYCLASS.rc

65. Edit MyDLL.h

66. Compile project "MyDLL" to get “MyDLL.dll" & " MyDLL.lib". It will be under "..\debug " Edit MyDLL.cpp

67. Edit MyDLL.def

68. Initial MyCSharp Project – step 1

69. Initial MyCSharp Project – step 2

70. Edit Form1.cs - 1

71. Edit Form1.cs - 2 private void OnClick(object sender, EventArgs e) { ShowHTBDialog() ; } private void button2_Click(object sender, EventArgs e) { Application.Exit() ; }

72. After Executing – calling MyDLL.dll

73. Initial MyMFC Project – step 1

74. Initial MyMFC Project – step 2

75. Initial MyMFC Project – step 3

76. Initial MyMFC Project – step 4

77. Initial MyMFC Project – step 5

78. Initial MyMFC Project – step 6

79. Edit MyMFCDlg.cpp void CMyMFCDlg::OnClick() { CMyDLLApp::ShowHTBDialog() ; }

80. After Executing – calling MyDLL.dll

81. Return GUI DLL

82. Initial MyDLL Project – step 1

83. Initial MyDLL Project – step 2

84. Initial MyDLL Project – step 3

85. Initial MyDLL Project – step 4

86. Edit MyDLL.rc

87. Add Dialog Class

88. Add Member Variables

89. Edit MyDLL.cpp

90. Edit MyDLL.def Compile project "MyDLL" to get “MyDLL.dll" & " MyDLL.lib". It will be under "..\debug "

91. Initial MyCSharp Project – step 1

92. Initial MyCSharp Project – step 2

93. Edit Form1.cs

94. After Executing – calling MyDLL.dll

95. DLL Call DLL

96. Initial Two DLL Project Like last example, we add two DLL :  “MyDLL_1” and “MyDLL_2”

97. Initial MyMFC DLL – edit MyMFCDLL.cpp int CMyMFCDLLApp::Dll_call_Dll() { h1DLL = LoadLibrary(_T("MyDLL_1.dll")); h2DLL = LoadLibrary(_T("MyDLL_2.dll")); if(h1DLL == NULL && h2DLL == NULL ) { return 1 ; } else if(h1DLL != NULL && h2DLL == NULL) { return 2 ; } else if(h1DLL == NULL && h2DLL != NULL ) { return 3 ; } else { return 4 ; } }

98. Initial MyCSharp Project - 1

99. Edit Form1.cs - 1 [DllImport("MyDLL_1.dll")] public static extern int ShowHTBDialog_1(); [DllImport("MyDLL_2.dll")] public static extern int ShowHTBDialog_2(); [DllImport("MyMFCDLL.dll")] public static extern int Dll_call_Dll();

100. Edit Form1.cs - 2 private void Form1_Load(object sender, EventArgs e) { int num; num = Dll_call_Dll(); if (num == 1) { MyButton_1.Enabled = false;MyButton_2.Enabled = false; } else if (num == 2) { MyButton_1.Enabled = true;MyButton_2.Enabled = false; } else if (num == 3) { MyButton_1.Enabled = false;MyButton_2.Enabled = true; } else { MyButton_1.Enabled = true;MyButton_2.Enabled = true; } }

101. Edit Form1.cs - 3 private void MyButton_1_Click(object sender, EventArgs e) { int num; num = ShowHTBDialog_1(); MyLebel_1.Text = num.ToString(); } private void MyButton_2_Click(object sender, EventArgs e) { int num; num = ShowHTBDialog_2(); MyLebel_2.Text = num.ToString(); }

102. After Executing - 1

103. After Executing - 2 remove MyDLL_1.dll

104. After Executing - 3 remove MyDLL_2.dll

105. After Executing - 3 remove MyMFCDLL.dll