Question

如何在for循环里用参数方法读取数据库中数据

SqlDataReader reader = null;
SqlCommand cmd = conn.CreateCommand();
for (int i = 0; i < 10; i++)
{
cmd.CommandText = "Select Answer from Question where QuestionId=@QUESTIONID";
cmd.Parameters.Add(new SqlParameter("@QUESTIONID", question[i]));
reader = cmd.ExecuteReader();
while (reader.Read())
{
ans[i] = reader.GetValue(0).ToString();
}
reader.Close();
}

在运行一次后出现异常:"参数@QUESTIONID已声明,变量在查询批次里必须唯一",
有什么方法可以在for循环里用参数方法读取数据库中数据呢??

Answer 1

for (int i = 0; i < 10; i++)
{
SqlDataReader reader = null;
SqlCommand cmd = conn.CreateCommand();

cmd.CommandText = "Select Answer from Question where QuestionId=@QUESTIONID";
cmd.Parameters.Add(new SqlParameter("@QUESTIONID", question[i]));
reader = cmd.ExecuteReader();
while (reader.Read())
{
ans[i] = reader.GetValue(0).ToString();
}
reader.Close();
}