public DataTable GetTopSearch()
        {
            DataSet dsKeyword = dal.GetKeyword();
            DataSet dsTopSearch = new DataSet();
            for (int i = 0; i < 4; i++)
            {
                string keyword = dsKeyword.Tables[0].Rows[i]["Name"].ToString();
                string condition = dsKeyword.Tables[0].Rows[i]["SearchCondition"].ToString();
                dsTopSearch.Merge(dal.GetTopSearch(keyword,condition));
            }
            return dsTopSearch.Tables[0].DefaultView.ToTable(true, "ID","Name","Author","Publisher","PublishDate","TypeName","Price","SalePrice","SavePrice","Rebate","ImagePath","ContentIntro");
        }

先把DataTable转成DataView,再通过DataView.ToTable()转回DataTable,ToTable()方法中有一个重载可以轻松消除重复行.
注:该重载的第二个参数为要保存的字段名.