TableAdapter / dataset / C＃中的参数

Question

SELECT        iddocs, iddep, year
FROM            docs
WHERE        (@p1 = @p2)

this.docsTableAdapter.FillYear(this.test1DataSet2.docs,string1,string2);

或

 this.docsTableAdapter.FillBy(this.test1DataSet2.docs,string1,string2);

无效。为什么呢？