C++通过ADO读写Excel文件

介绍

有时候我们需要从excel表格里导入、导出数据。其中一种方式就是通过ADO的方式。在这里，excel文件被当作数据库来处理，该方式不需要客户端安装Microsoft Excel，速度也够快。

连接字符串

这里有两种类型的连接字符串，第一种是针对xls格式的：

Provider=Microsoft.JET.OLEDB.4.0;Data Source=data.xls;Extended Properties="Excel 8.0"

第二种是针对xlsx格式的:

Provider=Microsoft.ACE.OLEDB.12.0;Data Source=data.xlsx; Extended Properties="Excel 12.0 Xml"

TESTHR定义

inline void TESTHR(HRESULT x) { if FAILED(x) _com_issue_error(x); };

写入

首先创建一个连接字符串：

TESTHR(pCon.CreateInstance(__uuidof(Connection))); TESTHR(pCon->Open(connStr, "", "", NULL));

然后创建Command对象和表，注意表名就是excel的页：

TESTHR(pCmd.CreateInstance(__uuidof(Command))); pCmd->ActiveConnection = pCon; pCmd->CommandText = "CREATE TABLE MySheet (A int, B varchar, C int, D int, E int, F int, G int, H int, I int, J varchar)"; pCmd->Execute(NULL, NULL, adCmdText);

创建Recordset并增加记录：

TESTHR(pRec.CreateInstance(__uuidof(Recordset))); pRec->Open("SELECT * FROM MySheet", _variant_t((IDispatch*)pCon), adOpenKeyset, adLockOptimistic, adCmdText); for(int i = 0; i < writeRows; ++i) { TESTHR(pRec->AddNew()); char str[11] = {0}; for(int j = 0; j < 10; ++j) str[j] = 'a' + (rand() % 26); pRec->Fields->GetItem("A")->Value = _variant_t(i); pRec->Fields->GetItem("B")->Value = _variant_t(str); pRec->Fields->GetItem("C")->Value = _variant_t(i); pRec->Fields->GetItem("D")->Value = _variant_t(i); pRec->Fields->GetItem("E")->Value = _variant_t(i); pRec->Fields->GetItem("F")->Value = _variant_t(i); pRec->Fields->GetItem("G")->Value = _variant_t(i); pRec->Fields->GetItem("H")->Value = _variant_t(i); pRec->Fields->GetItem("I")->Value = _variant_t(i); pRec->Fields->GetItem("J")->Value = _variant_t(str); } TESTHR(pRec->Update()); TESTHR(pRec->Close());

读取

创建和打开Recordset：

TESTHR(pRec.CreateInstance(__uuidof(Recordset))); TESTHR(pRec->Open("SELECT * FROM [Sheet1$]", connStr, adOpenStatic, adLockOptimistic, adCmdText));

如果excel的页不清楚，可以通过索引来查找：

TESTHR(pCon.CreateInstance(__uuidof(Connection))); TESTHR(pCon->Open(connStr, "", "", NULL)); pSchema = pCon->OpenSchema(adSchemaTables); for(int i = 0; i < sheetIndex; ++i) pSchema->MoveNext(); std::string sheetName = (char*)(_bstr_t)pSchema->Fields->GetItem("TABLE_NAME")->Value.bstrVal;

读取单元格的值：

while(!pRec->adoEOF) { for(long i = 0; i < pRec->Fields->GetCount(); ++i) { if(i > 0) stream << ";"; _variant_t v = pRec->Fields->GetItem(i)->Value; if(v.vt == VT_R8) stream << v.dblVal; if(v.vt == VT_BSTR) stream << (char*)(_bstr_t)v.bstrVal; } stream << std::endl; pRec->MoveNext(); }

参考资料

How to Read and Write Excel Files in C++ via ADOC++ using adodb to read excel file in 64-bit windows 7?AccessDatabaseEngine#install instruction

转载于:https://www.cnblogs.com/lkpp/p/ReadandWriteExcelFilesCppviaADO.html