Author: Pixelot12345
How to use the Excel.Application in C++Builder. Target device is Win64.
Use the ComObj, call in CreateOleObject (“Excel.Application”).
Including ComObj is required.
In C++Builder it is below.
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//// #include "System.Win.ComObj.hpp" |
Import from CSV file to Excel file.
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//// constexpr wchar_t const def_filename[] = L"C:EmbarcaderoExcel_testBook1.xlsx"; constexpr wchar_t const csv_file[] = L"C:EmbarcaderoExcel_testcsv.csv"; |
We will implement this process.
Prepare the TButton.
TButton is one in a simple form.
Next is the TButton OnClick event.
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///// constexpr wchar_t const def_excel_name[] = L"Excel.Application"; void __fastcall TForm1::Button1Click(TObject *Sender) { Variant ExcelApp = CreateOleObject(def_excel_name); try { Variant excel_book; Variant excel_sheet; UnicodeString excel_filename{def_filename}; try { ExcelApp.OlePropertySet("Visible", true); //setup Show Excel. excel_book = ExcelApp.OlePropertyGet("Workbooks"). OleFunction("Open",static_cast＜WideString＞(excel_filename)); //Open Excel File. excel_sheet = excel_book.OlePropertyGet("WorkSheets"). OlePropertyGet("Item", static_cast＜WideString＞("Sheet1")); //Select Sheet Name or Number. /* excel_sheet.OlePropertyGet("Cells"). OlePropertyGet("Item",1,2).OlePropertySet("Value",(WideString)L"文字"); //Write String Cell. cell_set(excel_sheet.OlePropertyGet("Cells"), 1, 1, "a"); //One Cell SetValue. */ load_csv_toCell(csv_file,excel_sheet.OlePropertyGet("Cells")); excel_book.OleProcedure("Save"); } __finally { excel_book = Unassigned(); excel_sheet = Unassigned(); } ExcelApp.OleProcedure("Quit"); //Quit Excel. } __finally { ExcelApp = Unassigned(); } } |
Sheet name is “Sheet 1”.
Next we will create two methods.
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//// void __fastcall TForm1::cell_set(System::Variant cells, int row_, int col, String value_) { try { //Write to one of the cell. cells.OlePropertyGet("Item",row_,col) .OlePropertySet("Value",static_cast＜WideString＞(value_)); } catch(...){} } |
Read the file with TStringList.And, you write to the specified cell.
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//// void __fastcall TForm1::load_csv_toCell(String csv_filename, System::Variant cells) { auto csv_ = {std::make_unique＜TStringList＞()}; std::wstringstream cols_; std::wstring value_ = L""; int column_count_{0}; try { (*csv_.begin())->LoadFromFile(csv_filename); //Read file. for (int i=0; i < (*csv_.begin())->Count; i++) //Retrieve one row. { //Separate one line. column_count_ = 0; //Column Count = 0. cols_.clear(); //Clear Rows. cols_.str(StringReplace((*csv_.begin())->Strings[i],L""", "",TReplaceFlags()＜＜rfReplaceAll).w_str()); while (std::getline(cols_, value_, L',')){ column_count_++; cell_set(cells,i + 1,column_count_,value_.c_str()); }; } } catch(...){} } |
Write the imported CSV file to Excel.
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Where do you close the excel object crated with CreateOleObject?
The CreateOleObject doesn’t actually create an object, as such, it returns an interface to the object and this is reference-counted.
The line;
ExcelApp = Unassigned();sets the OLE object to nil (unassigned) which correctly releases the interface.