Pivot Table with Multiply Key Columns in C#

I needed a pivot table to display a report to the user in my company, so I tried googling the best and practical way to do that. At first, I was interested in using MS Office components and just pass the data to the component and refresh the template so it will display the data I need. But, the thing is I will need the component also to be installed in the server, and this is not a really high priority apps to put the server in risk to not working for some time if there is anything wrong with the installation or the components it self. So, I decided using the data table manipulation and I found a good example on how to do that in weblogs of sql team here.

However, there is small modification I need to do since the function written there only accommodate single key column. After modified it, I was planning to put the update in comments of the page so I can contribute somehow. Unfortunately the comments is already closed, so I decided to put it here. Find it below. This pivot function is placed in a web service which is going to return a dataset containing the pivot table. After receiving it in the web app, I format the datagrid so it will display as the user need. Yay! Alhamdulillah. Hope it will be useful for other people who need it.

        /// <summary>
        /// Transform a table to a pivot table based on the given information.
        /// </summary>
        /// <param name="dataValues">The table which is going to be transformed to pivot table. The table should be sorted by the key colums, starting from most left part.</param>
        /// <param name="keyColumn">Array of String which contains the columns in dataValues that is going to be used as a keyColumn for display</param>
        /// <param name="pivotNameColumn">The Column name of the dataValues which is going to be displayed as pivot table's column</param>
        /// <param name="pivotValueColumn">The Column name of the dataValues which is going to be used to fill the value for the pivot table's column</param>
        /// <returns></returns>
        public static DataTable Pivot( DataTable dataValues, string[] keyColumn, string pivotNameColumn, string pivotValueColumn)
        {
            try
            {
                DataTable tmp = new DataTable();
                DataRow r;
                string[] LastKey = new string[keyColumn.Length];
                int i,keyColumnIndex, pValIndex, pNameIndex;
                string s;
                bool FirstRow = true;
                bool keyChanged = false;

                // Add non-pivot columns to the data table:
                pValIndex = dataValues.Columns.IndexOf(pivotValueColumn);
                pNameIndex = dataValues.Columns.IndexOf(pivotNameColumn);

                for (i = 0; i <= dataValues.Columns.Count - 1; i++)
                    if (i != pValIndex && i != pNameIndex)
                    {
                        tmp.Columns.Add(dataValues.Columns[i].ColumnName.ToString(), dataValues.Columns[i].DataType);
                    }
                r = tmp.NewRow();

                // now, fill up the table with the data:
                foreach (DataRow row in dataValues.Rows)
                {
                    // see if we need to start a new row
                    keyColumnIndex = 0;
                    keyChanged = false;
                    if (!FirstRow) 
                    {
                        while (!keyChanged && keyColumnIndex < keyColumn.Length)
                        {
                            if (row[keyColumn[keyColumnIndex]].ToString() != LastKey[keyColumnIndex])
                            {
                                keyChanged = true;
                            }
                            keyColumnIndex++;
                        }
                    }
                    else
                    {
                        for (keyColumnIndex = 0;keyColumnIndex<keyColumn.Length;keyColumnIndex++)
                        {
                            LastKey[keyColumnIndex] = row[keyColumn[keyColumnIndex]].ToString();
                        }                    
                    }
                                        
                    if (keyChanged || FirstRow)
                    {
                        // if this isn't the very first row, we need to add the last one to the table
                        if (!FirstRow)
                        {
                            tmp.Rows.Add(r);
                        }
                        r = tmp.NewRow();
                        
                        // Add all non-pivot column values to the new row:
                        for (i = 0; i <= dataValues.Columns.Count - 3; i++)
                        {
                            r[i] = row[tmp.Columns[i].ColumnName];
                        }
                        FirstRow = false;
                        
                        for (keyColumnIndex = 0;keyColumnIndex<keyColumn.Length;keyColumnIndex++)
                        {
                            LastKey[keyColumnIndex] = row[keyColumn[keyColumnIndex]].ToString();
                        }
                    }

                    // assign the pivot values to the proper column; add new columns if needed:
                    s = row[pNameIndex].ToString();
                    if (s.Length > 0)
                    {
                        if (!tmp.Columns.Contains(s) && s != null)
                        {
                            tmp.Columns.Add(s, dataValues.Columns[pValIndex].DataType);
                        }
                        r[s] = row[pValIndex];
                    }
                }
                // add that final row to the datatable:
                tmp.Rows.Add(r);

                // and that's it!
                return tmp;
            }
            catch (Exception)
            {    
                return null;
            }
        }