Question

我的任务是使用Access数据库并创建一个Excel文件，但我似乎无法创建 OleDb将使用的Excel文件。

Excel文件名将由运行该工具的工程师提供。 Access数据库中的每个数据表都将成为Excel文件中的工作表。

现在，我有一个不能克服的问题：如果Excel文件不存在，我就无法创建它！

internal const string XL_FMT = "Provider=Microsoft.{0}.OLEDB.{1};Data Source={2};Mode=ReadWrite;Extended Properties=\"Excel {1};HDR={3};IMEX=1;\"";
internal DataTable tableNames;
internal OleDbConnection oleCon;
private string conStr;

public OleBase(string connectionString) {
  conStr = connectionString;
  // Using the debugger, conStr is:
  // "Provider=Microsoft.ACE.OLEDB.12.0;" +
  // "Data Source=C:\\Users\\cp-jpool\\Documents\\Ecat5.xlsx;" +
  // "Mode=ReadWrite;Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=1;\""
  object[] param = new object[] { null, null, null, "TABLE" };
  oleCon = new OleDbConnection(conStr);
  oleCon.Open();
  tableNames = oleCon.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, param);
}

如果Excel文件不存在，每当我调用Open()时，我都会收到以下OleDbException：

“ Microsoft Access数据库引擎无法找到对象'C：\ Users \ cp-jpool \ Documents \ Ecat5.xlsx'。请确保该对象存在，并且您正确拼写其名称和路径名称。如果'C：\ Users \ cp-jpool \ Documents \ Ecat5.xlsx'不是本地对象，请检查您的网络连接或联系服务器管理员。“

所以，文件不存在，是吧？好吧，我尝试通过将CTor()修改为：

来创建它

public OleBase(string connectionString) {
  conStr = connectionString;
  object[] param = new object[] { null, null, null, "TABLE" };
  oleCon = new OleDbConnection(conStr);
  if (-1 < conStr.IndexOf(";IMEX=1;")) {
    string dsString = "Data Source=";
    int dsIndex = conStr.IndexOf(dsString);
    string conSub = conStr.Substring(dsIndex + dsString.Length);
    int firstCol = conSub.IndexOf(';');
    string xlPath = conSub.Substring(0, firstCol);
    if (!File.Exists(xlPath)) {
      File.Create(xlPath);
    }
  }
  oleCon.Open();
  tableNames = oleCon.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, param);
}

现在每当这段代码试图调用OleDbConnection的Open()方法时，我就会得到不同的OleDbException：

“Microsoft Access数据库引擎无法打开或写入文件”。它已由其他用户独占打开，或者您需要获得查看和写入其数据的权限。“

我甚至尝试使用 StreamWriter 创建Excel文件，用基本标题填充它：

public OleBase(string connectionString) {
  conStr = connectionString;
  object[] param = new object[] { null, null, null, "TABLE" };
  oleCon = new OleDbConnection(conStr);
  if (-1 < conStr.IndexOf(";IMEX=1;")) {
    string dsString = "Data Source=";
    int dsIndex = conStr.IndexOf(dsString);
    string conSub = conStr.Substring(dsIndex + dsString.Length);
    int firstCol = conSub.IndexOf(';');
    string xlPath = conSub.Substring(0, firstCol);
    using (StreamWriter xls = new StreamWriter(xlPath, false, Encoding.UTF8)) {
      xls.WriteLine("<?xml version=\"1.0\"?><?mso-application progid=\"Excel.Sheet\"?>");
      xls.WriteLine("<ss:Workbook xmlns:ss=\"urn:schemas-microsoft-com:office:spreadsheet\" ");
      xls.WriteLine("xmlns:o=\"urn:schemas-microsoft-com:office:office\" ");
      xls.WriteLine("xmlns:x=\"urn:schemas-microsoft-com:office:excel\" ");
      xls.WriteLine("xmlns:ss=\"urn:schemas-microsoft-com:office:spreadsheet\">");
      xls.WriteLine("<ss:Styles>");
      xls.WriteLine("<ss:Style ss:ID=\"Default\" ss:Name=\"Normal\"><ss:Alignment ss:Vertical=\"Bottom\"/><ss:Borders/><ss:Font/><ss:Interior/><ss:NumberFormat/><ss:Protection/></ss:Style>");
      xls.WriteLine("<ss:Style ss:ID=\"BoldColumn\"><ss:Font x:Family=\"Swiss\" ss:Bold=\"1\"/></ss:Style>");
      xls.WriteLine("<ss:Style ss:ID=\"StringLiteral\"><ss:NumberFormat ss:Format=\"@\"/></ss:Style>");
      xls.WriteLine("<ss:Style ss:ID=\"Decimal\"><ss:NumberFormat ss:Format=\"0.0000\"/></ss:Style>");
      xls.WriteLine("<ss:Style ss:ID=\"Integer\"><ss:NumberFormat ss:Format=\"0\"/></ss:Style>");
      xls.WriteLine("<ss:Style ss:ID=\"DateLiteral\"><ss:NumberFormat ss:Format=\"mm/dd/yyyy;@\"/></ss:Style>");
      xls.WriteLine("</ss:Styles>");
      xls.WriteLine("</ss:Workbook>");
      xls.Flush();
      xls.Close();
    }
  }
  oleCon.Open();
  tableNames = oleCon.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, param);
}

此代码生成了另一个OleDbException消息：

“外部表格不符合预期格式。”

我可以看到，OleDbConnection没有创建文件的方法，那么如何创建这个Excel文件以便我可以使用它？

Answer 1

我查看了各种网站上发布的大量代码，最终选择了一个非常适合我需要的版本。

我希望我将链接添加为书签，以便我可以在此处发布，但经过多次尝试失败后，我似乎停止了跟踪。

无论如何，如果它对其他人有帮助，这里是我最终得到的ExcelWriter课程（如何立即使用该课程）：

public class ExcelWriter : IDisposable {

  private XmlWriter writer;
  private static readonly DateTime NODATE = new DateTime(1900, 1, 1);

  public enum CellStyle { General, Number, Currency, DateTime, ShortDate };

  public ExcelWriter(string outputFileName) {
    if (!String.IsNullOrEmpty(outputFileName)) {
      XmlWriterSettings settings = new XmlWriterSettings();
      settings.Indent = true;
      writer = XmlWriter.Create(outputFileName, settings);
    } else {
      throw new Exception("Output path not supplied.");
    }
  }

  public void Close() {
    if (writer != null) {
      writer.Close();
      writer = null;
    } else {
      throw new NotSupportedException("Already closed.");
    }
  }

  public static bool HasValue(object obj) {
    if (obj != null) {
      if (obj != DBNull.Value) {
        string txt = obj.ToString();
        return (0 < txt.Length);
      }
    }
    return false;
  }

  public void WriteStartDocument() {
    if (writer != null) {
      writer.WriteProcessingInstruction("mso-application", "progid=\"Excel.Sheet\"");
      writer.WriteStartElement("ss", "Workbook", "urn:schemas-microsoft-com:office:spreadsheet");
      WriteExcelStyles();
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteEndDocument() {
    if (writer != null) {
      writer.WriteEndElement();
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  private void WriteExcelStyleElement(CellStyle style) {
    if (writer != null) {
      writer.WriteStartElement("Style", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteAttributeString("ID", "urn:schemas-microsoft-com:office:spreadsheet", style.ToString());
      writer.WriteEndElement();
    }
  }

  private void WriteExcelStyleElement(CellStyle style, string NumberFormat) {
    if (writer != null) {
      writer.WriteStartElement("Style", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteAttributeString("ID", "urn:schemas-microsoft-com:office:spreadsheet", style.ToString());
      writer.WriteStartElement("NumberFormat", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteAttributeString("Format", "urn:schemas-microsoft-com:office:spreadsheet", NumberFormat);
      writer.WriteEndElement();
      writer.WriteEndElement();
    }
  }

  private void WriteExcelStyles() {
    if (writer != null) {
      writer.WriteStartElement("Styles", "urn:schemas-microsoft-com:office:spreadsheet");
      WriteExcelStyleElement(CellStyle.General);
      WriteExcelStyleElement(CellStyle.Number, "General Number");
      WriteExcelStyleElement(CellStyle.DateTime, "General Date");
      WriteExcelStyleElement(CellStyle.Currency, "Currency");
      WriteExcelStyleElement(CellStyle.ShortDate, "Short Date");
      writer.WriteEndElement();
    }
  }

  public void WriteStartWorksheet(string name) {
    if (writer != null) {
      writer.WriteStartElement("Worksheet", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteAttributeString("Name", "urn:schemas-microsoft-com:office:spreadsheet", name);
      writer.WriteStartElement("Table", "urn:schemas-microsoft-com:office:spreadsheet");
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteEndWorksheet() {
    if (writer != null) {
      writer.WriteEndElement();
      writer.WriteEndElement();
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteExcelColumnDefinition(int columnWidth) {
    if (writer != null) {
      writer.WriteStartElement("Column", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteStartAttribute("Width", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteValue(columnWidth);
      writer.WriteEndAttribute();
      writer.WriteEndElement();
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteExcelUnstyledCell(string value) {
    if (writer != null) {
      writer.WriteStartElement("Cell", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteStartElement("Data", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteAttributeString("Type", "urn:schemas-microsoft-com:office:spreadsheet", "String");
      writer.WriteValue(value);
      writer.WriteEndElement();
      writer.WriteEndElement();
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteStartRow() {
    if (writer != null) {
      writer.WriteStartElement("Row", "urn:schemas-microsoft-com:office:spreadsheet");
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteEndRow() {
    if (writer != null) {
      writer.WriteEndElement();
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteExcelStyledCell(object value, CellStyle style) {
    if (writer != null) {
      writer.WriteStartElement("Cell", "urn:schemas-microsoft-com:office:spreadsheet");
      writer.WriteAttributeString("StyleID", "urn:schemas-microsoft-com:office:spreadsheet", style.ToString());
      writer.WriteStartElement("Data", "urn:schemas-microsoft-com:office:spreadsheet");
      switch (style) {
        case CellStyle.General:
          writer.WriteAttributeString("Type", "urn:schemas-microsoft-com:office:spreadsheet", "String");
          if (!HasValue(value)) {
            value = String.Empty; // DBNull.Value causes issues in an Excel cell.
          }
          break;
        case CellStyle.Number:
        case CellStyle.Currency:
          writer.WriteAttributeString("Type", "urn:schemas-microsoft-com:office:spreadsheet", "Number");
          if (!HasValue(value)) {
            value = 0;
          }
          break;
        case CellStyle.ShortDate:
        case CellStyle.DateTime:
          writer.WriteAttributeString("Type", "urn:schemas-microsoft-com:office:spreadsheet", "DateTime");
          if (!HasValue(value)) {
            value = NODATE;
          }
          break;
      }
      writer.WriteValue(value);
      writer.WriteEndElement();
      writer.WriteEndElement();
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  public void WriteExcelAutoStyledCell(object value) {
    if (writer != null) { //write the <ss:Cell> and <ss:Data> tags for something
      if (value is Int16 || value is Int32 || value is Int64 || value is SByte ||
          value is UInt16 || value is UInt32 || value is UInt64 || value is Byte) {
        WriteExcelStyledCell(value, CellStyle.Number);
      } else if (value is Single || value is Double || value is Decimal) { //we'll assume it's a currency
        WriteExcelStyledCell(value, CellStyle.Currency);
      } else if (value is DateTime) { //check if there's no time information and use the appropriate style
        WriteExcelStyledCell(value, ((DateTime)value).TimeOfDay.CompareTo(new TimeSpan(0, 0, 0, 0, 0)) == 0 ? CellStyle.ShortDate : CellStyle.DateTime);
      } else {
        WriteExcelStyledCell(value, CellStyle.General);
      }
    } else {
      throw new NotSupportedException("Cannot write after closing.");
    }
  }

  #region IDisposable Members

  public void Dispose() {
    if (writer != null) {
      writer.Close();
      writer = null;
    }
  }

  #endregion

}

示例：

以下是如何使用此类将整个DataSet写入Excel工作簿：

/// <summary> /// Saves data to the Access database to the Excel file specified by the filename /// </summary> public void Save(string excelFile) { using (ExcelWriter writer = new ExcelWriter(excelFile)) { writer.WriteStartDocument(); foreach (DataTable table in Dataset.Tables) { writer.WriteStartWorksheet(string.Format("{0}", SafeName(table.TableName))); // Write the worksheet contents writer.WriteStartRow(); //Write header row foreach (DataColumn col in table.Columns) { writer.WriteExcelUnstyledCell(col.Caption); } writer.WriteEndRow(); foreach (DataRow row in table.Rows) { //write data writer.WriteStartRow(); foreach (object o in row.ItemArray) { writer.WriteExcelAutoStyledCell(o); } writer.WriteEndRow(); } writer.WriteEndWorksheet(); // Close up the document } writer.WriteEndDocument(); writer.Close(); } }

我希望其他人能从中得到很多用处！

〜的Joep

Answer 2

使用模板（已存在的空excel文件）将该文件复制到具有所需名称的新excel文件。那就是你的创造！

Answer 3

我找到了一个有效的解决方案，只需删除这样的IMEX参数：

string connString = String.Format(
    "Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};" + 
    "Extended Properties=\"Excel 8.0;HDR={1}\"",
    file,
    (containsHeader ? "Yes" : "No")
);

当我尝试使用Excel 12.0时，它会创建一个文件，但我无法在Excel Application中打开它。

无论如何，这些东西适用于XLS文件。

Answer 4

要在文件上启用读写，您可以使用以下属性：模式

Provider=Microsoft.ACE.OLEDB.12.0;Data Source=EXCELFILENAME;Mode=ReadWrite;Extended Properties='Excel 12.0 Macro;HDR=YES;'

如何使用OleDb创建Excel数据库

4 个答案: