c# - 访问 App.Config 连接字符串时出现 TypeInitializationException

Question

我创建了一个静态实用程序类来简化对数据库的访问，当我运行代码“TypeInitializationException”时出现以下异常。

<connectionStrings>
  <add name="vistConnectionString" connectionString="XXXXX"/>
</connectionStrings>


static class DBUtility
{
    private static string dbConnection = ConfigurationManager.ConnectionStrings["vistConnectionString"].ConnectionString;

    public static string DbConnection
    {
        get { return dbConnection; }
    }  
}

如果我调用静态属性，那么我会收到一个 TypeInitializationException 异常

string s = DBUtility.DbConnection; // this line throws the exception

来自异常的消息是

Message=The type initializer for 'VIServiceToolServiceLibrary.Database.DBUtility' threw an exception.

Answer 1

使用下面的代码进行连接

var connectionString = ConfigurationManager.ConnectionStrings["vistConnectionString"].ConnectionString;
SqlConnection con = new SqlConnection(connectionString);
try { con.Open(); }