Pretty printing of the .NET DataTable from System.Data

DataTablePrinter.cs

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
 
namespace DataTablePrinter
{
    // Code originally written by grampa (http://stackoverflow.com/users/4607577/grampa)
    // Found here: http://stackoverflow.com/a/28729432/664178
    // Modified to handle DataTable and to work correctly with one column tables
    class DataTablePrinter
    {
        const string TOP_LEFT_JOINT = "┌";
        const string TOP_RIGHT_JOINT = "┐";
        const string BOTTOM_LEFT_JOINT = "└";
        const string BOTTOM_RIGHT_JOINT = "┘";
        const string TOP_JOINT = "┬";
        const string BOTTOM_JOINT = "┴";
        const string LEFT_JOINT = "├";
        const string JOINT = "┼";
        const string RIGHT_JOINT = "┤";
        const char HORIZONTAL_LINE = '─';
        const char PADDING = ' ';
        const string VERTICAL_LINE = "│";
 
        private static int[] GetMaxCellWidths(List<string[]> table)
        {
            int maximumCells = 0;
            foreach (Array row in table)
            {
                if (row.Length > maximumCells)
                    maximumCells = row.Length;
            }
 
            int[] maximumCellWidths = new int[maximumCells];
            for (int i = 0; i < maximumCellWidths.Length; i++)
                maximumCellWidths[i] = 0;
 
            foreach (Array row in table)
            {
                for (int i = 0; i < row.Length; i++)
                {
                    if (row.GetValue(i).ToString().Length > maximumCellWidths[i])
                        maximumCellWidths[i] = row.GetValue(i).ToString().Length;
                }
            }
 
            return maximumCellWidths;
        }
 
        public static string GetDataInTableFormat(DataTable dtable)
        {
            var table = new List<string[]>();
 
            table.Add(dtable.Columns.Cast<DataColumn>().Select(col => " " + col.ColumnName + " ").ToArray());
            foreach (DataRow row in dtable.Rows)
            {
                table.Add(row.ItemArray.Select(obj => obj.ToString()).ToArray());
            }
 
            StringBuilder formattedTable = new StringBuilder();
            Array nextRow = table.FirstOrDefault();
            Array previousRow = table.FirstOrDefault();
 
            if (table == null || nextRow == null)
                return String.Empty;
 
            // FIRST LINE:
            int[] maximumCellWidths = GetMaxCellWidths(table);
            for (int i = 0; i < nextRow.Length; i++)
            {
                if (i == 0 && i == nextRow.Length - 1)
                    formattedTable.AppendLine(String.Format("{0}{1}{2}", TOP_LEFT_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), TOP_RIGHT_JOINT));
                else if (i == 0)
                    formattedTable.Append(String.Format("{0}{1}", TOP_LEFT_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
                else if (i == nextRow.Length - 1)
                    formattedTable.AppendLine(String.Format("{0}{1}{2}", TOP_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), TOP_RIGHT_JOINT));
                else
                    formattedTable.Append(String.Format("{0}{1}", TOP_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
            }
 
            int rowIndex = 0;
            int lastRowIndex = table.Count - 1;
            foreach (Array thisRow in table)
            {
                // LINE WITH VALUES:
                int cellIndex = 0;
                int lastCellIndex = thisRow.Length - 1;
                foreach (object thisCell in thisRow)
                {
                    string thisValue = thisCell.ToString().PadLeft(maximumCellWidths[cellIndex], PADDING);
 
                    if (cellIndex == 0 && cellIndex == lastCellIndex)
                        formattedTable.AppendLine(String.Format("{0}{1}{2}", VERTICAL_LINE, thisValue, VERTICAL_LINE));
                    else if (cellIndex == 0)
                        formattedTable.Append(String.Format("{0}{1}", VERTICAL_LINE, thisValue));
                    else if (cellIndex == lastCellIndex)
                        formattedTable.AppendLine(String.Format("{0}{1}{2}", VERTICAL_LINE, thisValue, VERTICAL_LINE));
                    else
                        formattedTable.Append(String.Format("{0}{1}", VERTICAL_LINE, thisValue));
 
                    cellIndex++;
                }
 
                previousRow = thisRow;
 
                // SEPARATING LINE:
                if (rowIndex != lastRowIndex)
                {
                    nextRow = table[rowIndex + 1];
 
                    int maximumCells = Math.Max(previousRow.Length, nextRow.Length);
                    for (int i = 0; i < maximumCells; i++)
                    {
                        if (i == 0 && i == maximumCells - 1)
                        {
                            formattedTable.AppendLine(String.Format("{0}{1}{2}", LEFT_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), RIGHT_JOINT));
                        }
                        else if (i == 0)
                        {
                            formattedTable.Append(String.Format("{0}{1}", LEFT_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
                        }
                        else if (i == maximumCells - 1)
                        {
                            if (i > previousRow.Length)
                                formattedTable.AppendLine(String.Format("{0}{1}{2}", TOP_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), TOP_RIGHT_JOINT));
                            else if (i > nextRow.Length)
                                formattedTable.AppendLine(String.Format("{0}{1}{2}", BOTTOM_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), BOTTOM_RIGHT_JOINT));
                            else if (i > previousRow.Length - 1)
                                formattedTable.AppendLine(String.Format("{0}{1}{2}", JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), TOP_RIGHT_JOINT));
                            else if (i > nextRow.Length - 1)
                                formattedTable.AppendLine(String.Format("{0}{1}{2}", JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), BOTTOM_RIGHT_JOINT));
                            else
                                formattedTable.AppendLine(String.Format("{0}{1}{2}", JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), RIGHT_JOINT));
                        }
                        else
                        {
                            if (i > previousRow.Length)
                                formattedTable.Append(String.Format("{0}{1}", TOP_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
                            else if (i > nextRow.Length)
                                formattedTable.Append(String.Format("{0}{1}", BOTTOM_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
                            else
                                formattedTable.Append(String.Format("{0}{1}", JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
                        }
                    }
                }
 
                rowIndex++;
            }
 
            // LAST LINE:
            for (int i = 0; i < previousRow.Length; i++)
            {
                if (i == 0 && i == previousRow.Length - 1)
                    formattedTable.AppendLine(String.Format("{0}{1}{2}", BOTTOM_LEFT_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), BOTTOM_RIGHT_JOINT));
                else if (i == 0)
                    formattedTable.Append(String.Format("{0}{1}", BOTTOM_LEFT_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
                else if (i == previousRow.Length - 1)
                    formattedTable.AppendLine(String.Format("{0}{1}{2}", BOTTOM_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE), BOTTOM_RIGHT_JOINT));
                else
                    formattedTable.Append(String.Format("{0}{1}", BOTTOM_JOINT, String.Empty.PadLeft(maximumCellWidths[i], HORIZONTAL_LINE)));
            }
 
            return formattedTable.ToString();
        }
    }
}