Question

参数化查询 需要参数 @UserID，但未提供该参数

他说我没有提供参数，可是我写了呀，怎么也找不到错在哪里，请高手指教
//删除教师
public void Delete(TeacherEntity teacher)
{

IList<TeacherEntity> teachers = new List<TeacherEntity>();
SqlConnection cn = new SqlConnection(Connct_String);

string sql = "delete from TeacherInfo where UserID=@UserID";
SqlCommand cmd = new SqlCommand(sql, cn);
SqlParameter p1 = new SqlParameter("@UserID", teacher.UserID);

cmd.Parameters.Add(p1);

//cmd.Parameters.Add(new SqlParameter("@UserID", teacher.UserID));

cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}

Answer 1

teacher.UserID 肯定没有取到值
IList<TeacherEntity> teachers = new List<TeacherEntity>();
这个是干嘛的？