c# 随机函数

[zhdd_06]

我在做毕业设计管理系统,我首先给教师分组,比如说分成了5组
现在我要把学生随机分成5组,但是有一个要求:学生不能和指导教师在同一个组中
for(i=0;i<scount;i++)
{
int temp = rand.Next(a.Count - 1);//随机生成一个在在数组a大小范围内的非负数
m = (int)a[temp];//用以上的随机数temp为索引，得到数组a[temp]的值，我们设定为：m
b[i] = m;//将m赋值给b
if(!a.Contains(temp))
{
a.Add(temp);
dr = ds.Tables["student"].Rows[b[i]];
SqlCommand sqlcommand = new SqlCommand("update student set stu_group = @sgroup where stu_id = @stu_id",conn1);
sqlcommand.Parameters .Add(new SqlParameter("@stu_id",SqlDbType.Char,12));
sqlcommand.Parameters["@stu_id"].Value = dr["stu_id"].ToString();
if(i % j ==0 && jj <= sgroup)//j中记录了每组教师的人数,jj记录组别
{
mm = jj;
jj = jj + 1;
}
sqlcommand.Parameters.Add(new SqlParameter("@sgroup",SqlDbType.Int,4));
sqlcommand.Parameters["@sgroup"].Value = Convert.ToString(mm);
DataSet dset = new DataSet();
SqlDataAdapter sqldd = new SqlDataAdapter("select * from student s,teacher t,works w where s.stu_works = w.works_title and w.works_state='已选定' and t.tea_id = w.tea_id and s.stu_id = '"+dr["stu_id"].ToString()+"' and t.rejoin_group = '"+ mm +"'",conn1);
sqldd.Fill(dset);
int sum = dset.Tables[0].Rows.Count;
if(sum == 0)
{
sqlcommand.ExecuteNonQuery();
}
else
{
i = i - 1;
//a.RemoveAt(temp);
}
}
不能实现
请问如何实现呢?

[Kevin_LiuFeng]

太多了，懒的看，把最主要的问题表示出来。。。。

[csharp_start]

//举一个例子给你
List<string> student = new List<string>();
            List<string> teacher = new List<string>();
            List<string> result = new List<string>();
            student.AddRange(new string[] { "A1","B1","C1","D1","E1"});
            teacher.AddRange(new string[] { "A", "B", "C", "D", "E" });
            for (int i = 0; i < student.Count; i++)
            {
                bool isFindSelt = false;
                if(teacher.Contains(student[i].Substring(0,1)))
                {
                    teacher.Remove(student[i].Substring(0, 1));
                    isFindSelt = true;
                }
                Random rand = new Random();
                int index = rand.Next(0, teacher.Count - 1);
                string s = teacher[index];
                teacher.RemoveAt(index);
                if (isFindSelt)
                    teacher.Add(student[i].Substring(0, 1));
                result.Add(student[i] + "--" + s);
            }
            for (int i = 0; i < result.Count ; i++)
            {
                System.Windows.Forms.MessageBox.Show(result[i].ToString());
            }