How To: Best way to draw table in console app (C#)
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#.
Use String.Format with alignment values.
For example:
String.Format("|{0,5}|{1,5}|{2,5}|{3,5}|", arg0, arg1, arg2, arg3);
To create one formatted row.
You could do something like the following:
static int tableWidth = 73;
static void Main(string[] args)
{
Console.Clear();
PrintLine();
PrintRow("Column 1", "Column 2", "Column 3", "Column 4");
PrintLine();
PrintRow("", "", "", "");
PrintRow("", "", "", "");
PrintLine();
Console.ReadLine();
}
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);
}
}
Edit: thanks to @superlogical, you can now find and improve the following code in github!
I wrote this class based on some ideas here. The columns width is optimal, an it can handle object arrays with this simple API:
static void Main(string[] args)
{
IEnumerable<Tuple<int, string, string>> authors =
new[]
{
Tuple.Create(1, "Isaac", "Asimov"),
Tuple.Create(2, "Robert", "Heinlein"),
Tuple.Create(3, "Frank", "Herbert"),
Tuple.Create(4, "Aldous", "Huxley"),
};
Console.WriteLine(authors.ToStringTable(
new[] {"Id", "First Name", "Surname"},
a => a.Item1, a => a.Item2, a => a.Item3));
/* Result:
| Id | First Name | Surname |
|----------------------------|
| 1 | Isaac | Asimov |
| 2 | Robert | Heinlein |
| 3 | Frank | Herbert |
| 4 | Aldous | Huxley |
*/
}
Here is the class:
public static class TableParser
{
public static string ToStringTable<T>(
this IEnumerable<T> values,
string[] columnHeaders,
params Func<T, object>[] valueSelectors)
{
return ToStringTable(values.ToArray(), columnHeaders, valueSelectors);
}
public static string ToStringTable<T>(
this T[] values,
string[] columnHeaders,
params Func<T, object>[] valueSelectors)
{
Debug.Assert(columnHeaders.Length == valueSelectors.Length);
var arrValues = new string[values.Length + 1, valueSelectors.Length];
// Fill headers
for (int colIndex = 0; colIndex < arrValues.GetLength(1); colIndex++)
{
arrValues[0, colIndex] = columnHeaders[colIndex];
}
// Fill table rows
for (int rowIndex = 1; rowIndex < arrValues.GetLength(0); rowIndex++)
{
for (int colIndex = 0; colIndex < arrValues.GetLength(1); colIndex++)
{
arrValues[rowIndex, colIndex] = valueSelectors[colIndex]
.Invoke(values[rowIndex - 1]).ToString();
}
}
return ToStringTable(arrValues);
}
public static string ToStringTable(this string[,] arrValues)
{
int[] maxColumnsWidth = GetMaxColumnsWidth(arrValues);
var headerSpliter = new string('-', maxColumnsWidth.Sum(i => i + 3) - 1);
var sb = new StringBuilder();
for (int rowIndex = 0; rowIndex < arrValues.GetLength(0); rowIndex++)
{
for (int colIndex = 0; colIndex < arrValues.GetLength(1); colIndex++)
{
// Print cell
string cell = arrValues[rowIndex, colIndex];
cell = cell.PadRight(maxColumnsWidth[colIndex]);
sb.Append(" | ");
sb.Append(cell);
}
// Print end of line
sb.Append(" | ");
sb.AppendLine();
// Print splitter
if (rowIndex == 0)
{
sb.AppendFormat(" |{0}| ", headerSpliter);
sb.AppendLine();
}
}
return sb.ToString();
}
private static int[] GetMaxColumnsWidth(string[,] arrValues)
{
var maxColumnsWidth = new int[arrValues.GetLength(1)];
for (int colIndex = 0; colIndex < arrValues.GetLength(1); colIndex++)
{
for (int rowIndex = 0; rowIndex < arrValues.GetLength(0); rowIndex++)
{
int newLength = arrValues[rowIndex, colIndex].Length;
int oldLength = maxColumnsWidth[colIndex];
if (newLength > oldLength)
{
maxColumnsWidth[colIndex] = newLength;
}
}
}
return maxColumnsWidth;
}
}
Edit: I added a minor improvement - if you want the column headers to be the property name, add the following method to TableParser (note that it will be a bit slower due to reflection):
public static string ToStringTable<T>(
this IEnumerable<T> values,
params Expression<Func<T, object>>[] valueSelectors)
{
var headers = valueSelectors.Select(func => GetProperty(func).Name).ToArray();
var selectors = valueSelectors.Select(exp => exp.Compile()).ToArray();
return ToStringTable(values, headers, selectors);
}
private static PropertyInfo GetProperty<T>(Expression<Func<T, object>> expresstion)
{
if (expresstion.Body is UnaryExpression)
{
if ((expresstion.Body as UnaryExpression).Operand is MemberExpression)
{
return ((expresstion.Body as UnaryExpression).Operand as MemberExpression).Member as PropertyInfo;
}
}
if ((expresstion.Body is MemberExpression))
{
return (expresstion.Body as MemberExpression).Member as PropertyInfo;
}
return null;
}
There're several open-source libraries which allow console table formatting, ranging from simple (like the code samples in the answers here) to more advanced.
ConsoleTable
Judging by NuGet stats, the most popular library for formatting tables is ConsoleTable. Tables are constructed like this (from the readme file):
var table = new ConsoleTable("one", "two", "three");
table.AddRow(1, 2, 3)
.AddRow("this line should be longer", "yes it is", "oh");
Tables can be formatted using one of the predefined styles. It'll look like this:
--------------------------------------------------
| one | two | three |
--------------------------------------------------
| 1 | 2 | 3 |
--------------------------------------------------
| this line should be longer | yes it is | oh |
--------------------------------------------------
This library expects single-line cells with no formatting.
There're a couple of libraries based on ConsoleTable with slightly extended feature sets, like more line styles.
CsConsoleFormat
If you need more complex formatting, you can use CsConsoleFormat.† Here's a table generated from a process list (from a sample project):
new Grid { Stroke = StrokeHeader, StrokeColor = DarkGray }
.AddColumns(
new Column { Width = GridLength.Auto },
new Column { Width = GridLength.Auto, MaxWidth = 20 },
new Column { Width = GridLength.Star(1) },
new Column { Width = GridLength.Auto }
)
.AddChildren(
new Cell { Stroke = StrokeHeader, Color = White }
.AddChildren("Id"),
new Cell { Stroke = StrokeHeader, Color = White }
.AddChildren("Name"),
new Cell { Stroke = StrokeHeader, Color = White }
.AddChildren("Main Window Title"),
new Cell { Stroke = StrokeHeader, Color = White }
.AddChildren("Private Memory"),
processes.Select(process => new[] {
new Cell { Stroke = StrokeRight }
.AddChildren(process.Id),
new Cell { Stroke = StrokeRight, Color = Yellow, TextWrap = TextWrapping.NoWrap }
.AddChildren(process.ProcessName),
new Cell { Stroke = StrokeRight, Color = White, TextWrap = TextWrapping.NoWrap }
.AddChildren(process.MainWindowTitle),
new Cell { Stroke = LineThickness.None, Align = HorizontalAlignment.Right }
.AddChildren(process.PrivateMemorySize64.ToString("n0")),
})
)
The end result will look like this:
It supports any kind of table lines (several included and customizable), multi-line cells with word wrap, colors, columns growing based on content or percentage, text alignment etc.
† CsConsoleFormat was developed by me.
class ArrayPrinter
{
#region Declarations
static bool isLeftAligned = false;
const string cellLeftTop = "┌";
const string cellRightTop = "┐";
const string cellLeftBottom = "└";
const string cellRightBottom = "┘";
const string cellHorizontalJointTop = "┬";
const string cellHorizontalJointbottom = "┴";
const string cellVerticalJointLeft = "├";
const string cellTJoint = "┼";
const string cellVerticalJointRight = "┤";
const string cellHorizontalLine = "─";
const string cellVerticalLine = "│";
#endregion
#region Private Methods
private static int GetMaxCellWidth(string[,] arrValues)
{
int maxWidth = 1;
for (int i = 0; i < arrValues.GetLength(0); i++)
{
for (int j = 0; j < arrValues.GetLength(1); j++)
{
int length = arrValues[i, j].Length;
if (length > maxWidth)
{
maxWidth = length;
}
}
}
return maxWidth;
}
private static string GetDataInTableFormat(string[,] arrValues)
{
string formattedString = string.Empty;
if (arrValues == null)
return formattedString;
int dimension1Length = arrValues.GetLength(0);
int dimension2Length = arrValues.GetLength(1);
int maxCellWidth = GetMaxCellWidth(arrValues);
int indentLength = (dimension2Length * maxCellWidth) + (dimension2Length - 1);
//printing top line;
formattedString = string.Format("{0}{1}{2}{3}", cellLeftTop, Indent(indentLength), cellRightTop, System.Environment.NewLine);
for (int i = 0; i < dimension1Length; i++)
{
string lineWithValues = cellVerticalLine;
string line = cellVerticalJointLeft;
for (int j = 0; j < dimension2Length; j++)
{
string value = (isLeftAligned) ? arrValues[i, j].PadRight(maxCellWidth, ' ') : arrValues[i, j].PadLeft(maxCellWidth, ' ');
lineWithValues += string.Format("{0}{1}", value, cellVerticalLine);
line += Indent(maxCellWidth);
if (j < (dimension2Length - 1))
{
line += cellTJoint;
}
}
line += cellVerticalJointRight;
formattedString += string.Format("{0}{1}", lineWithValues, System.Environment.NewLine);
if (i < (dimension1Length - 1))
{
formattedString += string.Format("{0}{1}", line, System.Environment.NewLine);
}
}
//printing bottom line
formattedString += string.Format("{0}{1}{2}{3}", cellLeftBottom, Indent(indentLength), cellRightBottom, System.Environment.NewLine);
return formattedString;
}
private static string Indent(int count)
{
return string.Empty.PadLeft(count, '─');
}
#endregion
#region Public Methods
public static void PrintToStream(string[,] arrValues, StreamWriter writer)
{
if (arrValues == null)
return;
if (writer == null)
return;
writer.Write(GetDataInTableFormat(arrValues));
}
public static void PrintToConsole(string[,] arrValues)
{
if (arrValues == null)
return;
Console.WriteLine(GetDataInTableFormat(arrValues));
}
#endregion
static void Main(string[] args)
{
int value = 997;
string[,] arrValues = new string[5, 5];
for (int i = 0; i < arrValues.GetLength(0); i++)
{
for (int j = 0; j < arrValues.GetLength(1); j++)
{
value++;
arrValues[i, j] = value.ToString();
}
}
ArrayPrinter.PrintToConsole(arrValues);
Console.ReadLine();
}
}