I looked at lots of code posted on various websites, and eventually went with a version that worked really good for what I needed.
I wished I bookmarked the link so I could post it here, but after so many failed attempts it appears I stopped keeping track.
Anyway, if it helps others, here is the ExcelWriter class I ended up with (how to use the class is immediately following):
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
}
EXAMPLE:
Here is how to use this class to write an entire DataSet to an Excel workbook:
/// <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();
}
}
I hope others get a lot of usage out of this!
~JoeP
