C#

public class TextBoxTab : TabPage
{
   public RichTextBox TheTextBox
   {
      return this.richTextBox1; // assuming there is a RichTextBox named richTextBox1 on this control.
   }
}

tabControl1.TabPages.Add(new TextBoxTab());

// Read all the text from the file:
string text = File.ReadAllText(theFileName);

// Get the selected tab:
TextBoxTab selectedTab = tabControl1.SelectedTab as TextBoxTab;

// Set the text of the text box on the tab.
selectedTab.TheTextBox.Text = text;

static T[] CommaSeparatedStringToIEnumerable<T>(string values)<br />
{<br />
    List<string> list = new List<string>(values.Split(','));<br />
    List<T> ret = new List<T>();<br />
<br />
    foreach(string value in list)<br />
        ret.Add(ConvertValue<T>(value));<br />
    <br />
    return ret.ToArray();<br />
}<br />
<br />
static T ConvertValue<T>(object value)<br />
{<br />
    Converter<object, T> convert =<br />
    new Converter<object, T>(delegate(object val) { return (T)val; });<br />
<br />
    switch(typeof(T).ToString())<br />
    {<br />
        case "System.Int16":<br />
        case "System.Int32":<br />
            int RetInt;<br />
            if(int.TryParse(value.ToString(), out RetInt))<br />
                return convert(RetInt);<br />
            break;<br />
<br />
        case "System.Single":<br />
            float RetFloat;<br />
            if(float.TryParse(value.ToString(), out RetFloat))<br />
                return convert(RetFloat);<br />
            break;<br />
<br />
        case "System.Double":<br />
            double RetDouble;<br />
            if(double.TryParse(value.ToString(), out RetDouble))<br />
                return convert(RetDouble);<br />
            break;<br />
<br />
        default:<br />
            return convert(value);<br />
    }<br />
<br />
    return convert(value);<br />
}

public static IEnumerable<T> CommaSeperatedToIEnumerable<T>(string commaSeperatedValues, Converter<string, T> converter)
{
   foreach (string value in commaSeperatedValues.Split(','))
   {
      yield return converter(value);
   }
}

IEnumerable<int> myInts = CommaSeperatedSTringToIEnumerable<int>("1,2,3,4324,3423", int.Parse);

public static IEnumerable<T> Where<T>(IEnumerable<T> items, Predicate<T> criteria)
{
   foreach(T item in items)
   {
      if(criteria(item)) yield return item;
   }
}

int[] ints = {5, 10, 15, 20};
IEnumerable<int> evenIntegers = Linq.Where(ints, delegate(int i) { return i % 2 == 0; });

IEnumerable<int> evenIntegers = Linq.Where(ints, i => i % 2 == 0);

IEnumerable<int> evenIntegers = ints.Where(i => i % 2 == 0);

IEnumerable<int> evenIntegers = from ints where i % 2 == 0 select i;

var evenIntegers = from ints where i % 2 == 0 select i;