SQL选择查询同一属性的多个值 [英] SQL Select query of more than one value of a same Attribute

问题描述

我有一个包含许多属性的Sql数据库。从那里我想在一个名为getQuestion的数组中获取question属性的所有值。这是我的代码

I have a Sql Database with many attributes. From there i want to take all the value of question attribute in an array named getQuestion Here Is my code

vcon.Open();
  SqlCommand cmd = new SqlCommand("select question from examQuestion where tchId='123'", vcon);
  SqlDataReader dr = cmd.ExecuteReader();
  String[] getQuestion = { "" };
  int i = 0;

  while (dr.Read())
  {
      getQuestion[i] = dr.GetString(0);
      i++;
  }
  vcon.Close();

当数据库包含单个值时，它很好，但是当数据库有多个值时，它提供错误索引超出了数组的范围 。问题是什么？请帮我。我是ASP.Net的新手。

It is fine when database contain single value, But when database has more then one value it provide an Error "Index was outside the bounds of the array". What is the problem? Please Help me. I am very new at ASP.Net.

推荐答案

试试这种方式：

Try this way:

vcon.Open();
SqlCommand cmd = new SqlCommand("select question from examQuestion where tchId='123'", vcon);
SqlDataReader dr = cmd.ExecuteReader();
ArrayList getQuestion = new ArrayList();
int i = 0;

while (dr.Read())
{ 
    getQuestion.Add((string)dr["question"]);//or getQuestion.Add((string)dr[0]);
}
vcon.Close();

使用Generic List轻松的方式

use Generic List the Easy way

vcon.Open();
          SqlCommand cmd = new SqlCommand("select question from examQuestion where tchId='123'", vcon);
          SqlDataReader dr = cmd.ExecuteReader();
           System.Collections.Generic.List<string> LstQuestion = new System.Collections.Generic.List<string>();

          while (dr.Read())
          {
              LstQuestion.Add(dr.GetString(0));

          }
          vcon.Close();

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