Word wrap a string in multiple lines

static void Main(string[] args)
{
    List<string> lines = WrapText("Add some text", 300, "Calibri", 11);

    foreach (var item in lines)
    {
        Console.WriteLine(item);
    }

    Console.ReadLine();
}

static List<string> WrapText(string text, double pixels, string fontFamily, 
    float emSize)
{
    string[] originalLines = text.Split(new string[] { " " }, 
        StringSplitOptions.None);

    List<string> wrappedLines = new List<string>();

    StringBuilder actualLine = new StringBuilder();
    double actualWidth = 0;

    foreach (var item in originalLines)
    {
        FormattedText formatted = new FormattedText(item, 
            CultureInfo.CurrentCulture, 
            System.Windows.FlowDirection.LeftToRight,
            new Typeface(fontFamily), emSize, Brushes.Black);

        actualLine.Append(item + " ");
        actualWidth += formatted.Width;

        if (actualWidth > pixels)
        {
            wrappedLines.Add(actualLine.ToString());
            actualLine.Clear();
            actualWidth = 0;
        }
    }

    if(actualLine.Length > 0)
        wrappedLines.Add(actualLine.ToString());

    return wrappedLines;
}

Add WindowsBase and PresentationCore libraries.

Here's a version I came up with for my XNA game...

(Note that it's a snippet, not a proper class definition. Enjoy!)

using System;
using System.Text;
using Microsoft.Xna.Framework.Graphics;

public static float StringWidth(SpriteFont font, string text)
{
    return font.MeasureString(text).X;
}

public static string WrapText(SpriteFont font, string text, float lineWidth)
{
    const string space = " ";
    string[] words = text.Split(new string[] { space }, StringSplitOptions.None);
    float spaceWidth = StringWidth(font, space),
        spaceLeft = lineWidth,
        wordWidth;
    StringBuilder result = new StringBuilder();

    foreach (string word in words)
    {
        wordWidth = StringWidth(font, word);
        if (wordWidth + spaceWidth > spaceLeft)
        {
            result.AppendLine();
            spaceLeft = lineWidth - wordWidth;
        }
        else
        {
            spaceLeft -= (wordWidth + spaceWidth);
        }
        result.Append(word + space);
    }

    return result.ToString();
}

Thanks! I take a method from as-cii's answer with some changes, for using it in Windows Forms. I am using TextRenderer.MeasureText instead of FormattedText:

static List<string> WrapText(string text, double pixels, Font font)
{
    string[] originalLines = text.Split(new string[] { " " },
        StringSplitOptions.None);

    List<string> wrappedLines = new List<string>();

    StringBuilder actualLine = new StringBuilder();
    double actualWidth = 0;

    foreach (var item in originalLines)
    {
        int w = TextRenderer.MeasureText(item + " ", font).Width;
        actualWidth += w;

        if (actualWidth > pixels)
        {
            wrappedLines.Add(actualLine.ToString());
            actualLine.Clear();
            actualWidth = w;
        }

        actualLine.Append(item + " ");
    }

    if(actualLine.Length > 0)
        wrappedLines.Add(actualLine.ToString());

    return wrappedLines;
}

And a little remark: the line actualLine.Append(item + " "); needs to be placed after checking the width, because if actualWidth > pixels, this word must be in the next line.