类:
using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public class ConnClass
{
public ConnClass()
{

}
public void aaa(string str)
{
...
...
}

引用
ConnClass myClass = new ConnClass();
myClass.aaa("abc");