配置文件內容為
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
</configuration>
在配置節點中添加connectionStrings節點
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<!--數據庫連接字符串-->
<connectionStrings>
<add name="ConnectionToNorthwind"
connectionString="Data Source=localhost;Initial Catalog=數據庫名;UserID=sa;password=123456"
providerName="System.Data.SqlClient"/>
</connectionStrings>
</configuration>