autoscroll text

textBox1.SelectionStart = textBox1.Text.Length;
textBox1.SelectionLength = 0;
textBox1.ScrollToCaret();

ArrayList to array

using System.Collections;

ArrayList arrList = new ArrayList();

arrList.Add("one");
arrList.Add("two");
arrList.Add("three");

string[] strArray = arrList.ToArray(Type.GetType("System.String")) as string[];
return strArray;

Fill combobox with enum values

public enum CardDataType
{
    Unknown,
    Raw,
    RowChp
}

ctlDataType.DataSource = Enum.GetValues(typeof(CardDataType));
ctlDataType.SelectedItem = CardDataType.Unknown;

...
...
string strType = ctlDataType.SelectedItem.ToString();

or

CardDataType dataType;
string strDataType = "Raw";
dataType = (CardDataType)Enum.Parse(typeof(CardDataType), strDataType, true);

and eventually

ctlDataType.SelectedItem = dataType; 

// a volte da' problemi in fase di inizializzazione della UI;
// in questi casi si puo' ricorrere a Enum.GetNames()

foreach ( string name in Enum.GetNames(typeof(CardDataType)) )
{
    ctlDataType.Items.Add(name);
}

...

string strDataType = "Raw";
ctlDataType.SelectedItem = strDataType;

String to date/time conversion

public static DateTime atodt( string text )
{
    // Formati previsti : "AAAAMMGG" oppure "HHMM"
    DateTime rc = new DateTime();
    rc = DateTime.MinValue;

    string strDateTime = text.Trim();

    switch ( strDateTime.Length )
    {
        case 8 :
        {
            int year  = atoi(strDateTime.Substring(0,4));
            int month = atoi(strDateTime.Substring(4,2));
            int day   = atoi(strDateTime.Substring(6,2));

            rc = new DateTime(year,month,day);
        }
            break;

        case 4 :
        {
            int hours   = atoi(strDateTime.Substring(0,2));
            int minutes = atoi(strDateTime.Substring(2,2));

            rc = DateTime.MinValue;
            rc = rc.AddHours(hours);
            rc = rc.AddMinutes(minutes);
        }
            break;
    }        

    return rc;
}

public static TimeSpan atohhmmss( string text )
{
    // Formato previsto : "HHMMSS"
    TimeSpan rc = new TimeSpan();
    rc = TimeSpan.MinValue;

    string strDateTime = text.Trim();

    if ( strDateTime.Length == 6 )
    {
        int hours   = atoi(strDateTime.Substring(0,2));
        int minutes = atoi(strDateTime.Substring(2,2));
        int seconds = atoi(strDateTime.Substring(4,2));

        rc = new TimeSpan(hours,minutes,seconds);
    }        

    return rc;
}

String to int/double conversion

// Double to string conversion; always uses '.' as decimal separator
public static string dtoa( double value )
{
    string text = value.ToString("0.#######");
    return text.Replace(",",".");
}

// String to int conversion
// from http://www.c-sharpcenter.com/CSNET/string.asp
public static int atoi( string str )
{
    int sign      = 1;
    int TheNumber = 0;
    int tmp       = 0;
    int x         = 0;
    //int l         = (str.Length )-1;
    int l         = str.Length;

    if ( str.Length > 0 )
    {
        char [] c     = str.ToCharArray();

        if ('-'==c[0])
        {
            sign=-1;
            x=1;
        }
        for ( ; x<l; x++ )
        {
            if ((c[x]>='0')&&(c[x]<='9'))
            {
                tmp =(c[x]-'0');
                TheNumber = TheNumber * 10 + tmp;
            }
        }
    }
    return TheNumber * sign;
}

// String to double conversion; both '.' and ',' are treated as decimal separator
public static double atod( string str )
{
    int sign      = 1;
    double TheNumber = 0.0;
    int tmp       = 0;
    int x         = 0;
    //int l         = (str.Length )-1;
    int l         = str.Length;
    bool bDot     = false;
    int  normalizer = 1;          

    if ( str.Length > 0 )
    {
        char [] c     = str.ToCharArray();
        if ('-'==c[0])
        {
            sign=-1;
            x=1;
        }
        for ( ; x<l; x++ )
        {
            if ((c[x]>='0')&&(c[x]<='9'))
            {
                tmp =(c[x]-'0');
                TheNumber = TheNumber * 10.0 + tmp;
                if ( bDot )
                {
                    normalizer *= 10;
                }
            }
            else if ( c[x]=='.' || c[x]==',' )
            {
                bDot = true;
            }
        }
    }
    return (TheNumber * sign)/normalizer;
}