Question

I have found one open source project with the basic excel functionality, write cell, write int to cell, change color, font and stuff. One thing is missing, and its add Formula, and I was unable to implement it, so if any one know how to do it it would be great.

BIFF Formats:

internal sealed class BIFF
    {
        public const ushort DefaultColor = 0x7fff;

        public const ushort BOFRecord = 0x0209;
        public const ushort EOFRecord = 0x0A;

        public const ushort FontRecord = 0x0231;
        public const ushort FormatRecord = 0x001E;
        public const ushort LabelRecord = 0x0204;
        public const ushort WindowProtectRecord = 0x0019;
        public const ushort XFRecord = 0x0243;
        public const ushort HeaderRecord = 0x0014;
        public const ushort FooterRecord = 0x0015;
        public const ushort ExtendedRecord = 0x0243;
        public const ushort StyleRecord = 0x0293;
        public const ushort CodepageRecord = 0x0042;
        public const ushort NumberRecord = 0x0203;
        public const ushort ColumnInfoRecord = 0x007D;       

    }

example method for writing int and string

private void WriteStringCell(BinaryWriter writer, CellInfo cell)
        {
            string value;
            if (cell.Value is string)
                value = (string)cell.Value;
            else
                value = cell.Value.ToString();
            if (value.Length > 255)
                value = value.Substring(0, 255);
            ushort[] clData = { BIFF.LabelRecord, 0, 0, 0, 0, 0 };
            byte[] plainText = Encoding.GetEncoding(CodePage).GetBytes(value);
            int iLen = plainText.Length;
            clData[1] = (ushort)(8 + iLen);
            clData[2] = (ushort)cell.Row;
            clData[3] = (ushort)cell.Column;
            clData[4] = (ushort)cell.FXIndex;
            clData[5] = (ushort)iLen;
            WriteUshortArray(writer, clData);
            writer.Write(plainText);
        }
private void WriteNumberCell(BinaryWriter writer, CellInfo cell)
        {
            double dValue = Convert.ToDouble(cell.Value);
            ushort[] clData = { BIFF.NumberRecord, 14, (ushort)cell.Row, (ushort)cell.Column, (ushort)cell.FXIndex };
            WriteUshortArray(writer, clData);
            writer.Write(dValue);
        }

you can download source code from link provided. So what I want is to have a method WriteFromulaCell that will write formula into excel. No success at all.

Thanks in advance.

Answer 1

Try using NPOI, it has capability of adding formula, it’s open source and free, or there is a also another open source xls project: excellibrary. Both project claiming full BIFF implementation.