<span style="font-size:18px;">string conn = "Trusted_Connection = SSPI; Database = Application_site; Server = DELL-PC;";

SqlConnection mycon = new SqlConnection(conn);

mycon.Open();

SqlCommand read_Applicant_Class = new SqlCommand("select * from Applicant_Class", mycon);

SqlDataReader dr_Applicant_Class = read_Applicant_Class.ExecuteReader();</span>

</pre><pre name="code" class="csharp">此处略去一部分代码

<span style="font-size:18px;">
string Class_Date = (string)dr_Applicant_Class["Class_Date"];
string start = (string)dr_Applicant_Class["Start_Time"];        //报越界异常
string end = (string)dr_Applicant_Class["End_Time"];</span>

注：请务必确定不是访问地址越界，并且数据库表的列名没有拼写错误！！！

引起问题的原因初步判断是由于使用

<span style="font-size:18px;">string Class_Date = (string)dr_Applicant_Class["Class_Date"];</span>

<span style="font-size:18px;">dr_Applicant_Class.Read();</span>

解决方法如下：

在语句

<span style="font-size:18px;">string Class_Date = (string)dr_Applicant_Class["Class_Date"];</span>

<span style="font-size:18px;">dr_Applicant_Class.Close();
dr_Applicant_Class = read_Applicant_Class.ExecuteReader();
dr_Applicant_Class.Read();
</span>

问题解决

具体原因暂时未知。如有大神路过，还望能够告知一下个中原理，万分感激！