C#

NetworkCredential loginInfo = new NetworkCredential(gMailAccount, password);
MailMessage msg = new MailMessage();

msg.Sender = new MailAddress(from, displayname);
msg.ReplyTo = new MailAddress(from, displayname);
msg.From = new MailAddress(from, displayname);
msg.To.Add(new MailAddress(to, "Jassim Rahma"));
msg.Subject = subject;
message = message.Replace(@"\r\n", Environment.NewLine);
msg.Body = message;
msg.Priority = MailPriority.High;
msg.IsBodyHtml = true;

Attachment mail_attachment = new Attachment(Application.StartupPath + "\\rbuilder.log");

if (technical_data == true)
{
    msg.Attachments.Add(mail_attachment);
}

SmtpClient client = new SmtpClient("smtp.gmail.com");
client.Port = 587;
client.EnableSsl = true;
client.UseDefaultCredentials = false;
client.Credentials = loginInfo;
client.Send(msg);

MessageBox.Show("Thank you." +Environment.NewLine + Environment.NewLine + "Your email was receieved.", "Feedback", MessageBoxButtons.OK, MessageBoxIcon.Information);

return true;

private void treeViewRekeningen_AfterCheck(object sender, TreeViewEventArgs e)
{
	Boolean ret = false;
	TreeNode node = e.Node;
	if (node.Nodes != null)
	{
		foreach (TreeNode subnode in node.Nodes)
		{
			subnode.Checked = node.Checked;
		}
	}

	if (e.Node.Checked == true)
	{
		ret = true;
	}
	else
	{
		doorloopTreeview(node, ref ret);
	}
	if (ret == false)
	{
		Console.WriteLine("No node is checked")
	}
	else
	{
		Console.WriteLine("At least one node is checked")
	}
}

private void doorloopTreeview(TreeNode parent, ref Boolean gevonden)
{
	if (gevonden == false)
	{
		foreach (TreeNode node in parent.Nodes)
		{
			doorloopTreeview(node, ref gevonden);
		}
		if (parent.Checked == true)
			gevonden = true;
	}
}

void GetUserDetailsFromAD()
{
  string _userName = Environment.UserName;
  string _userDomain = Environment.UserDomainName;

//Use given URL
   using (DirectoryEntry de = new DirectoryEntry(string.Format("LDAP://URL /OU=XYZ,DC={0},DC=XYZ,DC=XYZ,DC=com",_userDomain)))
            {
                   //Create a text file to write details
                    TextWriter tw = new StreamWriter("C:\\LDAP.txt");

                    de.AuthenticationType = AuthenticationTypes.Secure |AuthenticationTypes.ReadonlyServer;
                    using (DirectorySearcher search = new DirectorySearcher(de))
                    {
                        search.Filter = "(sAMAccountName=" + _userName + ")";
                        search.PropertiesToLoad.Add("displayName");
                        search.PropertiesToLoad.Add("memberof");
                        SearchResult result = search.FindOne();


                        if (result != null)
                        {
                            _displayName = result.Properties["displayname"][0].ToString();

                            //Loop through all the groups that user is part of
                            foreach (object item in result.Properties["memberof"])
                            {

                                 //Write the groups to a text file
                                tw.WriteLine(item.ToString());

                              //Check whether the group in which user is present starts with ABC
                                if (item.ToString().StartsWith("CN=ABC,DC=DEF"))
				{
					//user is member of ABC group
				}
				else
				{
				       //user is not member
				}
                            }
                        } 
                    }

                    tw.Close();
               
              
            }
}

class MyListObject
{
int MyInt {get;set;}
string MyString {get;set;}
}

MyList.Find(delegate (MyListObject mlo) {return mlo.MyString == "hello";});

SqlTransaction mySqlTransaction = mySqlConnection.BeginTransaction()
try
{
   // First SQL command that is part of an atomic transaction
   using (SqlCommand sqlCommand = new SqlCommand("...", mySqlConnection, mySqlTransaction))
   {
      mySqlCommand.ExecuteScalar(); // or whatever
   }

   // Second SQL command that is part of an atomic transaction
   using (SqlCommand sqlCommand = new SqlCommand("...", mySqlConnection, mySqlTransaction))
   {
      mySqlCommand.ExecuteScalar(); // or whatever
   }

   mySqlTransaction.Commit();
}
catch
{
   mySqlTransaction.Rollback();
}