使用C＃进行ASP.NET Web开发：集中连接字符串

I am new to asp.net and C#. I am using a connection string in each and every page to connect to database and get results (the connection string is shown in the below code). Is there any way I can make the connection string centralized? So that I don't have to call it in each and every page?I am new to asp.net and C#. I am using a connec