.Net WebApi 使用Session

直接使用Session 会报错“未将对象引用设置到对象的实例”。

解决办法：在Global中添加如下代码

        /// <summary>
        /// 打开session
        /// </summary>
        public override void Init()
        {
            this.PostAuthenticateRequest += (sender, e) => HttpContext.Current.SetSessionStateBehavior(SessionStateBehavior.Required);
            base.Init();
        }

Session帮助类：

 public class SessionHelper
    {
        /// <summary>
        /// 写Session
        /// </summary>
        /// <typeparam name="T">Session键值的类型</typeparam>
        /// <param name="key">Session的键名</param>
        /// <param name="value">Session的键值</param>
        public static void WriteSession<T>(string key, T value)
        {
            if (key.Length == 0)
                return;
            HttpContext.Current.Session[key] = value;
            HttpContext.Current.Session.Timeout = 1;//有效期为1分钟
        }

        /// <summary>
        /// 写Session
        /// </summary>
        /// <param name="key">Session的键名</param>
        /// <param name="value">Session的键值</param>
        public static void WriteSession(string key, string value)
        {
            WriteSession<string>(key, value);
        }

        /// <summary>
        /// 读取Session的值
        /// </summary>
        /// <param name="key">Session的键名</param>        
        public static string GetSession(string key)
        {
            if (key.Length == 0)
                return string.Empty;
            return HttpContext.Current.Session[key] as string;
        }

        /// <summary>
        /// 读取Session的值
        /// </summary>
        /// <param name="key">Session的键名</param>        
        public static T GetSession<T>(string key)
        {
            if (key.Length == 0)
                return default(T);
            return (T)HttpContext.Current.Session[key];
        }

        /// <summary>
        /// 删除指定Session
        /// </summary>
        /// <param name="key">Session的键名</param>
        public static void RemoveSession(string key)
        {
            if (key.Length == 0)
                return;
            HttpContext.Current.Session.Contents.Remove(key);
        }
    }