C#基础问题？？

这是我一个类，我想在类中定义一些变量，在程序任何页面都能访问。
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient; namespace TTS
{
    class Cls_public
    {
        public String gstrUserID;
        public String gstrUserName;
        public String gstrPassWord;
        public String gstrDepartment;
        public String gstTel;
        public String gstrEmail;        public string UserID
        {
            get { return gstrUserID; }
            set { gstrUserID = value;}
        }
        public String UserName
        {
            get { return gstrUserName; }
            set { gstrUserName = value;}
        }
        public string PassWord
        {
            get { return gstrPassWord; }
            set { gstrPassWord = value;}
        }
        public String Department
        {
            get { return gstrDepartment; }
            set { gstrDepartment = value;}
        }
        public string Tel
        {
            get { return gstTel; }
            set { gstTel = value;}
        }
        public String Email
        {
            get { return gstrEmail; }
            set { gstrEmail = value;}
        }    }
}在登陆窗体的时候，给这些值赋值
 if (mydt.Rows.Count == 0)
            {
                MessageBox.Show("INVALID USER!", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
                this.txt_user.Text = "";
                this.txt_user.Focus();
            }
            else
            {
                if (mydr.Read())
                {
                    if (mydr["cUserID"].ToString() != null)
                    {
                        clsp.UserID = mydr["cUserID"].ToString();
                    }
                    else
                    {
                        clsp.UserID = "";
                    }                    if (mydr["vUserName"].ToString() != null)
                    {
                        clsp.UserName = mydr["vUserName"].ToString();
                    }
                    else
                    {
                        clsp.UserName = "";
                    }                    if (mydr["cPassword"].ToString() != null)
                    {
                        clsp.PassWord = mydr["cPassword"].ToString();
                    }
                    else
                    {
                        clsp.PassWord = "";
                    }                    if (mydr["vDeptName"].ToString() != null)
                    {
                        clsp.Department = mydr["vDeptName"].ToString();
                    }
                    else
                    {
                        clsp.Department = "";
                    }                    if (mydr["vTelNo"].ToString() != null)
                    {
                        clsp.Tel = mydr["vTelNo"].ToString();
                    }
                    else
                    {
                        clsp.Tel = "";
                    }
                    if (mydr["vEmailAddress"].ToString() != null)
                    {
                        clsp.Email = mydr["vEmailAddress"].ToString();
                    }
                    else
                    {
                        clsp.Email = "";
                    }                }现在是 在其它的页面我们去访问这些公共的数值。。如果重新new的话，那又得重新赋值，这些是基础的公共值，登陆的时候就得到，
在程序后面很多地方要用到。。
请问怎么去实现。。？