将DataTable插入Excel使用Microsoft Access数据库引擎通过OleDb
今天我遇到了使用本网站上的OleDbConnection从Microsoft Excel文件读取数据的说明： OLE DB提供程序
这使我可以读取Excel文件中的所有数据：
private const string EXCEL_CON = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};" + @"Extended Properties='Excel 8.0;HDR=Yes;IMEX=1;'"; public DataTable ExtractExcel(string fullFilename, string tableName) { var table = new DataTable(); string strCon = string.Format(EXCEL_CON, fullFilename); using (var xlConn = new System.Data.OleDb.OleDbConnection(strCon)) { ConnectionState initialState = xlConn.State; try { if ((initialState & ConnectionState.Open) != ConnectionState.Open) { xlConn.Open(); } string sql = string.Format("SELECT * FROM `{0}`;", tableName); using (var cmd = new System.Data.OleDb.OleDbCommand(sql, xlConn)) { table.Load(cmd.ExecuteReader()); } } finally { // it seems like Access does not always close the connection if ((initialState & ConnectionState.Open) != ConnectionState.Open) { xlConn.Close(); } } } return table; }
当我插入数据时，步骤1是删除Microsoft Access数据库中的现有表格，以防添加，更改或删除列：
public void InsertExcel(OleDbConnection dbConn, DataTable table) { ConnectionState initState = dbConn.State; try { if ((initState & ConnectionState.Open) != ConnectionState.Open) { dbConn.Open(); } string sql = string.Format("SELECT * FROM {0};", table.TableName); DataTable original = new DataTable(); using (OleDbCommand cmd = new OleDbCommand(sql, dbConn)) { try { original.Load(cmd.ExecuteReader()); } catch (Exception) { // table does not exist } } if (0 < original.Rows.Count) { sql = string.Format("DROP TABLE {0};", table.TableName); using (OleDbCommand cmd = new OleDbCommand(sql, dbConn)) { cmd.ExecuteNonQuery(); } } // **************** // CODE NEEDED HERE // **************** } finally { if ((initState & ConnectionState.Open) != ConnectionState.Open) { dbConn.Close(); } } }
执行DROP TABLE命令（在CODE NEEDED HERE部分）后，我需要以某种方式将信息插入到DataTable中 。
如果我没有任何一种主键，列名或列数据types，我将如何插入表？
OleDbParameter有AddWithValue方法，允许添加数据而不必知道数据types。 有没有类似的东西，我可以使用转储整个DataTable （或DataSet ）？
这是一个static class我通过合并我已经find或开发的各种代码构build。 这个你要注意的主要方法是ExportToExcelOleDb ，它给定一个DataSet和一个连接string，将这个DataSet写到你select的Excel文件中，格式化为DataSet 。
请注意，Access Engine写入Excel的方式有一个“错误” – 写入Excel工作簿时，不能保留数据types，这意味着所有数据types都以Excel TEXT / STRINGforms写入。 无论如何，这是…
// Structures used for conversion between data-types. private struct ExcelDataTypes { public const string NUMBER = "NUMBER"; public const string DATETIME = "DATETIME"; public const string TEXT = "TEXT"; // also works with "STRING". } private struct NETDataTypes { public const string SHORT = "int16"; public const string INT = "int32"; public const string LONG = "int64"; public const string STRING = "string"; public const string DATE = "DateTime"; public const string BOOL = "Boolean"; public const string DECIMAL = "decimal"; public const string DOUBLE = "double"; public const string FLOAT = "float"; } /// <summary> /// Routine to export a given DataSet to Excel. For each DataTable contained /// in the DataSet the overloaded routine will create a new Excel sheet based /// upon the currently selected DataTable. The proceedure loops through all /// DataRows in the selected DataTable and pushes each one to the specified /// Excel file using ADO.NET and the Access Database Engine (Excel is not a /// prerequisit). /// </summary> /// <param name="dataSet">The DataSet to be written to Excel.</param> /// <param name="connectionString">The connection string.</param> /// <param name="fileName">The Excel file name to export to.</param> /// <param name="deleteExistFile">Delete existing file?</param> public static void ExportToExcelOleDb(DataSet dataSet, string connectionString, string fileName, bool deleteExistFile) { // Support for existing file overwrite. if (deleteExistFile && File.Exists(fileName)) File.Delete(fileName); ExportToExcelOleDb(dataSet, connectionString, fileName); } /// <summary> /// Overloaded version of the above. /// </summary> /// <param name="dataSet">The DataSet to be written to Excel.</param> /// <param name="connectionString">The SqlConnection string.</param> /// <param name="fileName">The Excel file name to export to.</param> public static bool ExportToExcelOleDb(DataSet dataSet, string connectionString, string fileName) { try { // Check for null set. if (dataSet != null && dataSet.Tables.Count > 0) { using (OleDbConnection connection = new OleDbConnection(String.Format(connectionString, fileName))) { // Initialise SqlCommand and open. OleDbCommand command = null; connection.Open(); // Loop through DataTables. foreach (DataTable dt in dataSet.Tables) { // Build the Excel create table command. string strCreateTableStruct = BuildCreateTableCommand(dt); if (String.IsNullOrEmpty(strCreateTableStruct)) return false; command = new OleDbCommand(strCreateTableStruct, connection); command.ExecuteNonQuery(); // Puch each row into Excel. for (int rowIndex = 0; rowIndex < dt.Rows.Count; rowIndex++) { command = new OleDbCommand(BuildInsertCommand(dt, rowIndex), connection); command.ExecuteNonQuery(); } } } } return true; } catch (Exception eX) { Utils.ErrMsg(eX.Message); return false; } } /// <summary> /// Build the various sheet names to be inserted based upon the /// number of DataTable provided in the DataSet. This is not required /// for XCost purposes. Coded for completion. /// </summary> /// <param name="connectionString">The connection string.</param> /// <returns>String array of sheet names.</returns> private static string[] BuildExcelSheetNames(string connectionString) { // Variables. DataTable dt = null; string[] excelSheets = null; using (OleDbConnection schemaConn = new OleDbConnection(connectionString)) { schemaConn.Open(); dt = schemaConn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null); // No schema found. if (dt == null) return null; // Insert 'TABLE_NAME' to sheet name array. int i = 0; excelSheets = new string[dt.Rows.Count]; foreach (DataRow row in dt.Rows) excelSheets[i++] = row["TABLE_NAME"].ToString(); } return excelSheets; } /// <summary> /// Routine to build the CREATE TABLE command. The conversion of /// .NET to Excel data types is also handled here (supposedly!). /// Help: http://support.microsoft.com/kb/316934/en-us. /// </summary> /// <param name="dataTable"></param> /// <returns>The CREATE TABLE command string.</returns> private static string BuildCreateTableCommand(DataTable dataTable) { // Get the type look-up tables. StringBuilder sb = new StringBuilder(); Dictionary<string, string> dataTypeList = BuildExcelDataTypes(); // Check for null data set. if (dataTable.Columns.Count <= 0) return null; // Start the command build. sb.AppendFormat("CREATE TABLE [{0}] (", BuildExcelSheetName(dataTable)); // Build column names and types. foreach (DataColumn col in dataTable.Columns) { string type = ExcelDataTypes.TEXT; if (dataTypeList.ContainsKey(col.DataType.Name.ToString().ToLower())) { type = dataTypeList[col.DataType.Name.ToString().ToLower()]; } sb.AppendFormat("[{0}] {1},", col.Caption.Replace(' ', '_'), type); } sb = sb.Replace(',', ')', sb.ToString().LastIndexOf(','), 1); return sb.ToString(); } /// <summary> /// Routine to construct the INSERT INTO command. This does not currently /// work with the data type miss matches. /// </summary> /// <param name="dataTable"></param> /// <param name="rowIndex"></param> /// <returns></returns> private static string BuildInsertCommand(DataTable dataTable, int rowIndex) { StringBuilder sb = new StringBuilder(); // Remove whitespace. sb.AppendFormat("INSERT INTO [{0}$](", BuildExcelSheetName(dataTable)); foreach (DataColumn col in dataTable.Columns) sb.AppendFormat("[{0}],", col.Caption.Replace(' ', '_')); sb = sb.Replace(',', ')', sb.ToString().LastIndexOf(','), 1); // Write values. sb.Append("VALUES ("); foreach (DataColumn col in dataTable.Columns) { string type = col.DataType.ToString(); string strToInsert = String.Empty; strToInsert = dataTable.Rows[rowIndex][col].ToString().Replace("'", "''"); sb.AppendFormat("'{0}',", strToInsert); //strToInsert = String.IsNullOrEmpty(strToInsert) ? "NULL" : strToInsert; //String.IsNullOrEmpty(strToInsert) ? "NULL" : strToInsert); } sb = sb.Replace(',', ')', sb.ToString().LastIndexOf(','), 1); return sb.ToString(); } /// <summary> /// Build the Excel sheet name. /// </summary> /// <param name="dataTable"></param> /// <returns></returns> private static string BuildExcelSheetName(DataTable dataTable) { string retVal = dataTable.TableName; if (dataTable.ExtendedProperties.ContainsKey(TABLE_NAME_PROPERTY)) retVal = dataTable.ExtendedProperties[TABLE_NAME_PROPERTY].ToString(); return retVal.Replace(' ', '_'); } /// <summary> /// Dictionary for conversion between .NET data types and Excel /// data types. The conversion does not currently work, so I am /// puching all data upto excel as Excel "TEXT" type. /// </summary> /// <returns></returns> private static Dictionary<string, string> BuildExcelDataTypes() { Dictionary<string, string> dataTypeLookUp = new Dictionary<string, string>(); // I cannot get the Excel formatting correct here!? dataTypeLookUp.Add(NETDataTypes.SHORT, ExcelDataTypes.NUMBER); dataTypeLookUp.Add(NETDataTypes.INT, ExcelDataTypes.NUMBER); dataTypeLookUp.Add(NETDataTypes.LONG, ExcelDataTypes.NUMBER); dataTypeLookUp.Add(NETDataTypes.STRING, ExcelDataTypes.TEXT); dataTypeLookUp.Add(NETDataTypes.DATE, ExcelDataTypes.DATETIME); dataTypeLookUp.Add(NETDataTypes.BOOL, ExcelDataTypes.TEXT); dataTypeLookUp.Add(NETDataTypes.DECIMAL, ExcelDataTypes.NUMBER); dataTypeLookUp.Add(NETDataTypes.DOUBLE, ExcelDataTypes.NUMBER); dataTypeLookUp.Add(NETDataTypes.FLOAT, ExcelDataTypes.NUMBER); return dataTypeLookUp; }
我希望这对你有一些用处。
注意。 我意识到这种答案是不被接受的，但是我花了一些时间来开发这个方法，最终没有用到它，而是转向COM / interop。 这是一个耻辱不分享！