public class ExcelConvert
	{
		public int toExcelDate(int nDay, int nMonth, int nYear) {
			// Excel/Lotus 123 have a bug with 29-02-1900. 1900 is not a
			// leap year, but Excel/Lotus 123 think it is...
			if (nDay == 29 && nMonth == 02 && nYear==1900)
				return 60;

			// DMY to Modified Julian calculation with an extra substraction of 2415019.
			long nSerialDate = 	(int)(( 1461 * ( nYear + 4800 + (int)(( nMonth - 14 ) / 12) ) ) / 4) +
						(int)(( 367 * ( nMonth - 2 - 12 * ( ( nMonth - 14 ) / 12 ) ) ) / 12) -
						(int)(( 3 * ( (int)(( nYear + 4900 + (int)(( nMonth - 14 ) / 12) ) / 100) ) ) / 4) +
						nDay - 2415019 - 32075;

			if (nSerialDate < 60) {
				// Because of the 29-02-1900 bug, any serial date 
				// under 60 is one off... Compensate.
				nSerialDate--;
			}

			return (int)nSerialDate;
		}

		public object convertArray(object anarray) {
			object[,] ary = (object[,])anarray;
			
			int rows = ary.GetUpperBound(0) + 1;
			int cols = ary.GetUpperBound(1) + 1;

			for ( int row = 0 ; row < rows ; row++ ) {
				for ( int col = 0 ; col < cols ; col++ ) {
					object result;
					string value = (string) ary[row,col];
					try {
						result = Convert.ToDouble(value);
					}
					catch ( FormatException e ) {
						// Try Date 	
						try {
							DateTime dt = DateTime.Parse(value);
							result = toExcelDate(dt.Day, dt.Month, dt.Year);						
						}
						catch ( FormatException e2 ) {
							result = value;
						}
					}
				
					ary[row,col] = result;
				}
			}

			return ary;
		}
	}