C#

using System.Windows.Forms;<br />
using System.Collections.Generic;<br />
using System.ComponentModel;<br />
<br />
class testForm : Form {<br />
<br />
Storage s = new Storage();<br />
<br />
testForm() {<br />
<br />
Customer c = new Customer();<br />
c.Id = "J";<br />
c.Name = "John";<br />
List<Customer> l = new List<Customer>();<br />
l.Add(c);<br />
<br />
NullableComBobox cm = new NullableComBobox();<br />
cm.DisplayMember = "Name";<br />
cm.ValueMember = "Id";<br />
cm.DataSource = l;<br />
<br />
s.CustId = "J";<br />
cm.DataBindings.Add("SelectedValue", s, "CustId");<br />
<br />
Controls.Add(cm);<br />
Button b = new Button();<br />
b.Top = 80;<br />
b.Click += new System.EventHandler(b_Click);<br />
Controls.Add(b);<br />
}<br />
<br />
void b_Click(object sender, System.EventArgs e) {<br />
<br />
if (s.CustId == null)<br />
MessageBox.Show("Value is null");<br />
else<br />
MessageBox.Show("Value is NOT null "+s.CustId.ToString());<br />
}<br />
<br />
class Customer {<br />
public string Id { get; set; }<br />
public string Name { get; set; }<br />
}<br />
<br />
class Storage {<br />
public string CustId { get; set; }<br />
}<br />
<br />
static void Main() {<br />
Application.Run(new testForm());<br />
}<br />
}<br />
<br />
/// <summary><br />
/// Combobx which stores null value for empty Text.<br />
/// </summary><br />
public class NullableComBobox : ComboBox {<br />
<br />
protected override void OnValidating(CancelEventArgs e) {<br />
<br />
if (Text.Trim().Length == 0) {<br />
SelectedIndex = -1;<br />
base.OnValidating(e);<br />
return;<br />
}<br />
<br />
int pos = FindString(Text.Trim());<br />
<br />
if (pos >= 0) {<br />
SelectedIndex = pos;<br />
base.OnValidating(e);<br />
return;<br />
}<br />
<br />
e.Cancel = true;<br />
MessageBox.Show("Invalid entry");<br />
base.OnValidating(e);<br />
}<br />
} 

nlmLogVariableOpaqueVal OBJECT-TYPE<br />
    SYNTAX      Opaque<br />
    MAX-ACCESS  read-only<br />
    STATUS      current<br />
    DESCRIPTION<br />
     "The value when nlmLogVariableType is 'opaque'."<br />
    ::= { nlmLogVariableEntry 12 }<br />
<br />
<br />
--<br />
-- Conformance<br />
--<br />
<br />
notificationLogMIBConformance OBJECT IDENTIFIER ::=<br />
    { notificationLogMIB 3 }<br />
notificationLogMIBCompliances OBJECT IDENTIFIER ::=<br />
    { notificationLogMIBConformance 1 }<br />
notificationLogMIBGroups      OBJECT IDENTIFIER ::=<br />
    { notificationLogMIBConformance 2 }<br />
<br />
-- Compliance

Regex objIdentifiers = new Regex(@"(?<name>[a-z][\d\w0-9-]*).*(\n|\s|\t)*OBJECT IDENTIFIER.*(\s|\t|\n)*::=(\s|\t)*{(\s|\t)*(?<enterprise>[\d\w0-9-]*)(\s|\t)*(?<number>[0-9])(\s|\t)*}");<br />
<br />
MatchCollection matches = objIdentifiers.Matches(s);</number></enterprise></name>

notificationLogMIBGroups      OBJECT IDENTIFIER ::=<br />
-- Comment<br />
    { notificationLogMIBConformance 2 }