Excel Automation in C++

[Learned]

This the code I have from a book which I am not able to run. I have figured out other errors but it is still stuck in with linker errors.

I am using Excel 2002.

These are the linker errors:

------ Build started: Project: test, Configuration: Debug Win32 ------
Compiling...
testExcelDriver.cpp
Linking...
testExcelDriver.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall ExcelDriver::~ExcelDriver(void)" (??1ExcelDriver@@UAE@XZ) referenced in function _main
testExcelDriver.obj : error LNK2019: unresolved external symbol "public: void __thiscall ExcelDriver::SetActiveSheet(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?SetActiveSheet@ExcelDriver@@QAEXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function _main
testExcelDriver.obj : error LNK2019: unresolved external symbol "public: void __thiscall ExcelDriver::AddWorkbook(void)" (?AddWorkbook@ExcelDriver@@QAEXXZ) referenced in function _main
testExcelDriver.obj : error LNK2019: unresolved external symbol "public: void __thiscall ExcelDriver::OpenExcel(void)" (?OpenExcel@ExcelDriver@@QAEXXZ) referenced in function _main
testExcelDriver.obj : error LNK2019: unresolved external symbol "public: __thiscall ExcelDriver::ExcelDriver(void)" (??0ExcelDriver@@QAE@XZ) referenced in function _main
C:\Documents and Settings\Saket1\Desktop\C++ Practice\test\Debug\test.exe : fatal error LNK1120: 5 unresolved externals
Build log was saved at "file://c:\Documents and Settings\Saket1\Desktop\C++ Practice\test\Debug\BuildLog.htm"
test - 6 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

The rest of the code are:
--------------Imports.hpp---------------------------------

#import "C:\Program Files\Common Files\Microsoft Shared\office10\mso.dll" rename("DocumentProperties", "DocumentPropertiesXL") rename("RGB", "RBGXL") 
#import "C:\Program Files\Common Files\Microsoft Shared\VBA\VBA6\vbe6ext.olb" 
#import "C:\Program Files\Microsoft Office\Office10\EXCEL.EXE" rename("DialogBox", "DialogBoxXL") rename("RGB", "RBGXL") rename("DocumentProperties", "DocumentPropertiesXL") rename("ReplaceText", "ReplaceTextXL") rename("CopyFile", "CopyFileXL") no_dual_interfaces

-----------------ExcelDriver.hpp---------------------------------------

#ifndef ExcelDriver_hpp
#define ExcelDriver_hpp
#include <iostream>
#include "imports.hpp"

class ExcelDriver
{
private:
	Excel::_ApplicationPtr m_pXL;
public:
	ExcelDriver();
	ExcelDriver(const ExcelDriver& source);
	virtual ~ExcelDriver();

	Excel::_ApplicationPtr Application() const;

	// Operations
	void OpenExcel();
	void CloseExcel();
	void AddWorkbook();
	void SetActiveSheet(const std::string& name);
};


#endif

------------------------ExcelDriver.cpp--------------------

#include "ExcelDriver.hpp"

// Constructors & destructor
ExcelDriver::ExcelDriver()
{ // Default constructor
}

ExcelDriver::ExcelDriver(const ExcelDriver& source)
{ // Copy constructor
}

ExcelDriver::~ExcelDriver()
{ // Destructor
}

// Selectors
Excel::_ApplicationPtr ExcelDriver::Application() const
{ // Return Excel application

	return m_pXL;
}

// Modifiers

// Operations
void ExcelDriver::OpenExcel()
{ // Open Excel application

	try
	{
		m_pXL.CreateInstance(L"Excel.Application");
		m_pXL->Visible=VARIANT_TRUE;
	}
	catch(_com_error&)
	{ // For now ignore error
	}
}

void ExcelDriver::CloseExcel()
{ // Close Excel

	try
	{
		m_pXL->Quit();
	}
	catch(_com_error&)
	{ // For now ignore error
	}
}

void ExcelDriver::AddWorkbook()
{ // Add a workbook

	try
	{
		m_pXL->Workbooks->Add((long)Excel::xlWorksheet);
	}
	catch(_com_error&)
	{ // For now ignore error
	}
}

void ExcelDriver::SetActiveSheet(const std::string& name)
{ // Make a sheet active

	Excel::_WorkbookPtr pWorkbook=m_pXL->ActiveWorkbook;
	Excel::_WorksheetPtr pWorksheet=pWorkbook->Worksheets->GetItem(name.c_str());
	pWorksheet->Activate();
}

-------------testExcelDriver.cpp---------------

#include "exceldriver.hpp"

int main()
{
		CoInitialize(NULL);

		ExcelDriver myFirst;

		myFirst.OpenExcel();

		myFirst.AddWorkbook();
		myFirst.SetActiveSheet("Daniel");
		
		CoUninitialize();

		return 0;
}

[D_Drmmr]

Are you compiling ExcelDriver.cpp?
This code seems like it shouldn't compile.

void ExcelDriver::OpenExcel()
{ // Open Excel application

	try
	{
		m_pXL.CreateInstance(L"Excel.Application");
		m_pXL->Visible=VARIANT_TRUE;
	}
	catch(_com_error&)
	{ // For now ignore error
	}
}

[Learned]

Yes it compiles fine. But why would you say that it should not compile? What change do you suggest?

[Paul McKenzie]

Yes it compiles fine. But why would you say that it should not compile?

Because the code below is not valid C++, unless the operator -> has been overloaded:

m_pXL.CreateInstance(L"Excel.Application");
m_pXL->Visible=VARIANT_TRUE;

If operator -> has been overloaded, you need to tell us what it has been overloaded to do. Otherwise, you can't use "." and "->" at the same time in the context you are showing us.

"Visible" is just a member variable, and if you create an object, you access members and functions of that object using ".", so what would have been expected is:

m_pXL.Visible=VARIANT_TRUE;

If you have a pointer to an object, then you access members using "->". Then the expected code would have looked like this:

	Excel::_ApplicationPtr* m_pXL;
//...

m_pXL->CreateInstance(L"Excel.Application");
m_pXL->Visible=VARIANT_TRUE;

As to the error, your linker is telling you that it cannot find those functions. This could mean that you do not have your project or makefile set up correctly to include the file(s) you're compiling.

Regards,

Paul McKenzie