获取含有字符串数组里元素的数据，并批量删除

 var urList = allcategory.Select(u => new { u.ArticleCategoryId }).ToArray();
string[] objectIdStr = new string[urList.Length];
int i = 0;
foreach (var item in urList)
  objectIdStr[i++] = item.ArticleCategoryId.ToString();
dataList = dataList.Where(a => objectIdStr.Contains(a.ArticleCategoryId));
db.Sys_UserRelation.RemoveRange(dataList);