注释:

connectionstring:连接字符串名称
127.0.0.1:数据库地址,此处为本机名
sa:数据库登录名
pwd:数据库登录密码
Power:数据库名称

第一种写法

写法:

  <configuration>
  <appSettings>
  <add key="connectionstring" value="server=127.0.0.1;uis=sa;pwd=123456;database=Power"/>
  </appSettings>
  </congiguration>

调用方式:

string rode= ConfigurationManager.AppSettings["connectionstring"];

第二种写法

写法:

  <configuration>
  <appSettings>
  <add name="connectionstring" connectionString="server=127.0.0.1;Uid=sa;pwd=123456;Database=Power"/>
  </appSettings>
  </congiguration>

调用方式:

string  connectionstr =ConfigurationManager.ConnectionStrings["connectionstring"].ConnectionString;

第三种写法

写法:

<connectionStrings>
<appSettings>
<add name="connectionstring" connectionString="Data source=localhost,8085;Initial Catalog=Power;Integrated Security=SSPI;"  providerName="System.Data.SqlClient"/>
</appSettings>
</connectionStrings>

调用方式:

string  connectionstr =ConfigurationManager.ConnectionStrings["connectionstring"].ConnectionString;