C# 将列数据加载到复选框列表中

我试图将r1、r2、r3列加载到复选框列表中，但输出不是我期望的结果

我的数据库中的数据

问题r1 r2 r3

我是谁？A、B、C

输出（我的复选框列表中的项目）

A

预期产出

A

B

C

我试图将r1、r2、r3添加到DataTextField中，但asp.net不允许我这样做=(

DataSourceID=“SqlDataSource1”DataTextField=“r1”DataValueField=“r1”>

尝试将此作为选择命令：

SELECT [r1] AS [Option] FROM [ExerciseTable] WHERE ([Question] = @Question)
UNION
SELECT [r2] AS [Option] FROM [ExerciseTable] WHERE ([Question] = @Question)
UNION
SELECT [31] AS [Option] FROM [ExerciseTable] WHERE ([Question] = @Question)

---

它不起作用，输出正在数据绑定：“System.Data.DataRowView”不包含名为“r1”的属性。哦，我将其更改为option并重试，它会返回缺少对象或列名或为空的输出。对于SELECT INTO语句，请验证每一列都有名称。对于其他语句，请查找空别名。别名定义为不允许使用“”或[]。请将别名更改为有效名称。

SELECT [r1] AS [Option] FROM [ExerciseTable] WHERE ([Question] = @Question)
UNION
SELECT [r2] AS [Option] FROM [ExerciseTable] WHERE ([Question] = @Question)
UNION
SELECT [31] AS [Option] FROM [ExerciseTable] WHERE ([Question] = @Question)