Asp.net，to_date函数

Question

我想更新oracle db中的记录。但它在转换之前给了我错误＆＃34;日期格式图片结束...＆＃34;我使用to_date函数。列的数据类型是DATE。 这是我的查询

             var updateddate = DateTime.Now;
              var testing=  this.hidvalue.Value;
             var idrow = id.Text;
            var anserrow = lblanswer.Text;
            var weightpwd = lblweighted.Text;
            var solvetimerow =lblsolvetime.Text;
            var updatedby = Session["Name"];
string queryDuppass = "Update ADU.QAT_DATA set Question='" + idrow + "',Answer='" + anserrow + "', Question_Weighted='" + weightpwd + "',  Resolve_Estimated_Time='" + solvetimerow + "', Updated_By='" + updatedby + "', Updated_Date= to_date('" + updateddate + "','mm-dd-yyyy hh12:mi:ss'" + ")" + " where ID='" + testing + "'";