SqlParameter构造函数的临界边缘

windows2003无法安装Windows Live Installer，将就着用CE写了。在对代码的精简下（绿色-->红色代码），由于没有对SqlDbType进行相应的指定类型，出现了object与SqlDbType的异常(系统无法捕获)，主要是针对0，找了好久才发现！偷懒反被0耍了，哈哈。当然下面的精简只适合在修改少数字段的情况下方便，对于数目较多的情况下还是采用对象模型方便。

            Jasen.Business.Operate operate = new Jasen.Business.Operate();
            Jasen.Business.BaseModel baseModel = new Jasen.Business.BaseModel();
            Jasen.Business.SysOwnuser ownuser = new Jasen.Business.SysOwnuser();*/
            for (int i = 0; i < dgdList.Items.Count; i++)
            {
                DataGridItem item = dgdList.Items[i];
                if (((CheckBox)item.FindControl("chkSelect")).Checked == true)
                {
                    int ID = int.Parse(((CheckBox)item.FindControl("chkSelect")).Text.ToString());
                  /*  baseModel = operate.GetModelby(m_ownuser, "sys_ownuser", "where ownuser_id=" + ID);
                    ownuser .Equals(baseModel );
                    ownuser .state = 0;
                    ownuser.ownuser_id = int.Parse(((CheckBox)item.FindControl("chkSelect")).Text.ToString());
                    operate.Update(m_ownuser, "sys_ownuser", "ownuser_id");*/
                    DBTool.ExecuteNonQuery("update sys_ownuser set state =@state where ownuser_id=@ownuser_id", new SqlParameter("@state", 0), new SqlParameter("@ownuser_id", ID));
                  
                    //Operate Log
                    Jasen.Business.OperateLog log = new OperateLog();
                    log.InsertOperationLog("XX", "XX【" + item.Cells[1].Text + "】", OwnUser.Name.ToString(), Request.UserHostAddress.ToString());
                }
            }

           new SqlParameter("@state", 0)，对于构造函数public SqlParameter(string parameterName,Object value）和public SqlParameter(string parameterName,SqlDbType dbType，0就处于边缘地带了，断点测试发现sqlhelper中

          foreach (SqlParameter p in commandParameters)
          {
             if( p != null )
             {
                // Check for derived output value with no value assigned
                if ( ( p.Direction == ParameterDirection.InputOutput ||  p.Direction == ParameterDirection.Input ) && (p.Value == null))
                {
                  p.Value = DBNull.Value;
                }
               command.Parameters.Add(p);
            }
          }

        传入@state时系统无法判断0（开始没有设置类型）的类型,默认为null，p.Value 设置成了DBNull.Value;

        因此以后有必要针对于0的时候还是不要偷懒，起码设置下0的类型。不要以为sqlparameter构造函数中，0就是个object，传入进去就可以了，嘿嘿。

        吃一堑长一智！！！