我正在尝试将连接字符串写入Web.config,如下所示：
<connectionStrings>
<add name="Dbconnection" connectionString="Server=localhost;
Database=OnlineShopping ; Integrated Security=True"/>
</connectionStrings >
并从中读取：
string strcon =
ConfigurationManager.ConnectionStrings["Dbconnection"].ConnectionString;
sqlConnection DbConnection = new sqlConnection(strcon);
当运行程序时,我得到一个错误,因为null引用.但是当我使用这个代码：
sqlConnection DbConnection = new sqlConnection(); DbConnection.ConnectionString = "Server=localhost; Database=OnlineShopping ; Integrated Security=True";
我没有得到任何错误,程序正常工作！
问题是什么？
解决方法
添加引用添加System.Configuration： –
System.Configuration.ConfigurationManager.
ConnectionStrings["connectionStringName"].ConnectionString;
<connectionStrings>
<add name="Dbconnection"
connectionString="Server=localhost; Database=OnlineShopping ; Integrated Security=True" ;
providerName="System.Data.sqlClient" />
</connectionStrings>
