ToNameValueCollection

/// <summary>
/// Splits a string into a NameValueCollection, where each "namevalue" is separated by
/// the "OuterSeparator". The parameter "NameValueSeparator" sets the split between Name and Value.
/// Example: 
///             String str = "param1=value1;param2=value2";
///             NameValueCollection nvOut = str.ToNameValueCollection(';', '=');
///             
/// The result is a NameValueCollection where:
///             key[0] is "param1" and value[0] is "value1"
///             key[1] is "param2" and value[1] is "value2"
/// </summary>
/// <param name="str">String to process</param>
/// <param name="OuterSeparator">Separator for each "NameValue"</param>
/// <param name="NameValueSeparator">Separator for Name/Value splitting</param>
/// <returns></returns>
public static NameValueCollection ToNameValueCollection(this String str, Char OuterSeparator, Char NameValueSeparator)
{
    NameValueCollection nvText = null;
    str = str.TrimEnd(OuterSeparator);
    if (!String.IsNullOrEmpty(str))
    {
        String[] arrStrings = str.TrimEnd(OuterSeparator).Split(OuterSeparator);

        foreach (String s in arrStrings)
        {
            Int32 posSep = s.IndexOf(NameValueSeparator);
            String name = s.Substring(0, posSep);
            String value = s.Substring(posSep + 1);
            if (nvText == null)
                nvText = new NameValueCollection();
            nvText.Add(name, value);
        }
    }
    return nvText;
}

String a = "param1=value1;param2=value2";
NameValueCollection nv = a.ToNameValueCollection(';', '=');