How To: Best way to draw table in console app (C#)

Question

I have an interesting question. Imagine I have a lot of data changing in very fast intervals. I want to display that data as a table in console app. f.ex:

-------------------------------------------------------------------------
|    Column 1     |    Column 2     |    Column 3     |    Column 4     |
-------------------------------------------------------------------------
|                 |                 |                 |                 |
|                 |                 |                 |                 |
|                 |                 |                 |                 |
-------------------------------------------------------------------------

How to keep things fast and how to fix column widths ? I know how to do that in java, but I don't how it's done in C#.

Answer 1

public static void ToPrintConsole(this DataTable dataTable)
    {
        // Print top line
        Console.WriteLine(new string('-', 75));

        // Print col headers
        var colHeaders = dataTable.Columns.Cast<DataColumn>().Select(arg => arg.ColumnName);
        foreach (String s in colHeaders)
        {
            Console.Write("| {0,-20}", s);
        }
        Console.WriteLine();

        // Print line below col headers
        Console.WriteLine(new string('-', 75));

        // Print rows
        foreach (DataRow row in dataTable.Rows)
        {
            foreach (Object o in row.ItemArray)
            {
                Console.Write("| {0,-20}", o.ToString());
            }
            Console.WriteLine();
        }

        // Print bottom line
        Console.WriteLine(new string('-', 75));
    }

Answer 2

This is an improvement to a previous answer. It adds support for values with varying lengths and rows with a varying number of cells. For example:

┌──────────┬─────────┬──────────────────────────┬────────────────┬─────┬───────┐
│Identifier│     Type│               Description│  CPU Credit Use│Hours│Balance│
├──────────┼─────────┼──────────────────────────┼────────────────┼─────┼───────┘
│ i-1234154│ t2.small│       This is an example.│         3263.75│  360│
├──────────┼─────────┼──────────────────────────┼────────────────┼─────┘
│ i-1231412│ t2.small│  This is another example.│         3089.93│
└──────────┴─────────┴──────────────────────────┴────────────────┘

Here is the code:

public class ArrayPrinter
{
    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(List<string[]> table)
    {
        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.Append(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.Append(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)
                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();
    }
}

Answer 3

Use MarkDownLog library (you can find it on NuGet)

you can simply use the extension ToMarkdownTable() to any collection, it does all the formatting for you.

 Console.WriteLine(
    yourCollection.Select(s => new
                    {
                        column1 = s.col1,
                        column2 = s.col2,
                        column3 = s.col3,
                        StaticColumn = "X"
                    })
                    .ToMarkdownTable());

Output looks something like this:

Column1  | Column2   | Column3   | StaticColumn   
--------:| ---------:| ---------:| --------------
         |           |           | X              

Answer 4

You could do something like the following:

static int tableWidth = 77;

static void PrintLine()
{
    Console.WriteLine(new string('-', tableWidth));
}

static void PrintRow(params string[] columns)
{
    int width = (tableWidth - columns.Length) / columns.Length;
    string row = "|";

    foreach (string column in columns)
    {
        row += AlignCentre(column, width) + "|";
    }

    Console.WriteLine(row);
}

static string AlignCentre(string text, int width)
{
    text = text.Length > width ? text.Substring(0, width - 3) + "..." : text;

    if (string.IsNullOrEmpty(text))
    {
        return new string(' ', width);
    }
    else
    {
        return text.PadRight(width - (width - text.Length) / 2).PadLeft(width);
    }
}

Answer 5

I wanted variable-width columns, and I didn't particularly care about the box characters. Also, I needed to print some extra information for each row.

So in case anyone else needs that, I'll save you few minutes:

public class TestTableBuilder
{

    public interface ITextRow
    {
        String Output();
        void Output(StringBuilder sb);
        Object Tag { get; set; }
    }

    public class TableBuilder : IEnumerable<ITextRow>
    {
        protected class TextRow : List<String>, ITextRow
        {
            protected TableBuilder owner = null;
            public TextRow(TableBuilder Owner)
            {
                owner = Owner;
                if (owner == null) throw new ArgumentException("Owner");
            }
            public String Output()
            {
                StringBuilder sb = new StringBuilder();
                Output(sb);
                return sb.ToString();
            }
            public void Output(StringBuilder sb)
            {
                sb.AppendFormat(owner.FormatString, this.ToArray());
            }
            public Object Tag { get; set; }
        }

        public String Separator { get; set; }

        protected List<ITextRow> rows = new List<ITextRow>();
        protected List<int> colLength = new List<int>();

        public TableBuilder()
        {
            Separator = "  ";
        }

        public TableBuilder(String separator)
            : this()
        {
            Separator = separator;
        }

        public ITextRow AddRow(params object[] cols)
        {
            TextRow row = new TextRow(this);
            foreach (object o in cols)
            {
                String str = o.ToString().Trim();
                row.Add(str);
                if (colLength.Count >= row.Count)
                {
                    int curLength = colLength[row.Count - 1];
                    if (str.Length > curLength) colLength[row.Count - 1] = str.Length;
                }
                else
                {
                    colLength.Add(str.Length);
                }
            }
            rows.Add(row);
            return row;
        }

        protected String _fmtString = null;
        public String FormatString
        {
            get
            {
                if (_fmtString == null)
                {
                    String format = "";
                    int i = 0;
                    foreach (int len in colLength)
                    {
                        format += String.Format("{{{0},-{1}}}{2}", i++, len, Separator);
                    }
                    format += "\r\n";
                    _fmtString = format;
                }
                return _fmtString;
            }
        }

        public String Output()
        {
            StringBuilder sb = new StringBuilder();
            foreach (TextRow row in rows)
            {
                row.Output(sb);
            }
            return sb.ToString();
        }

        #region IEnumerable Members

        public IEnumerator<ITextRow> GetEnumerator()
        {
            return rows.GetEnumerator();
        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return rows.GetEnumerator();
        }

        #endregion
    }



    static void Main(String[] args)
    {
        TableBuilder tb = new TableBuilder();
        tb.AddRow("When", "ID", "Name");
        tb.AddRow("----", "--", "----");

        tb.AddRow(DateTime.Now, "1", "Name1");
        tb.AddRow(DateTime.Now, "1", "Name2");

        Console.Write(tb.Output());
        Console.WriteLine();

        // or

        StringBuilder sb = new StringBuilder();
        int i = 0;
        foreach (ITextRow tr in tb)
        {
            tr.Output(sb);
            if (i++ > 1) sb.AppendLine("more stuff per line");
        }
        Console.Write(sb.ToString());
    }
}

Output:

When                 ID  Name
----                 --  ----
2/4/2013 8:37:44 PM  1   Name1
2/4/2013 8:37:44 PM  1   Name2

When                 ID  Name
----                 --  ----
2/4/2013 8:37:44 PM  1   Name1
more stuff per line
2/4/2013 8:37:44 PM  1   Name2
more stuff per line

Answer 6

It's easier in VisualBasic.net!

If you want the user to be able to manually enter data into a table:

Console.Write("Enter Data For Column 1: ")
    Dim Data1 As String = Console.ReadLine
    Console.Write("Enter Data For Column 2: ")
    Dim Data2 As String = Console.ReadLine

    Console.WriteLine("{0,-20} {1,-10} {2,-10}", "{Data Type}", "{Column 1}", "{Column 2}")
    Console.WriteLine("{0,-20} {1,-10} {2,-10}", "Data Entered:", Data1, Data2)

    Console.WriteLine("ENTER To Exit: ")
    Console.ReadLine()

It should look like this: