删除数组重复值

好比，在数据库中查询到某个字段的值 aa,bb,aa,dd,cc,bb,aa,ee，如今要把重复的值去掉，那么咱们能够把该值查询出来，而后赋值到数组，删除重复值。

好比咱们把查询到的值放到datatable里，这里演示第一行第二列的操做。多行的话，for循环便可。

   string mydata = ds.Tables["data"].Rows[i][1].ToString();
                string ls_str = mydata;
                string[] str_num = ls_str.Split(',');
                ArrayList al = new ArrayList();
                for (int j = 0; j< str_num.Length;j++)
                {

                    //判断是否已经存在                     if (al.Contains(str_num[j]) == false)                     {                         al.Add(str_num[j]);                     }                 }                 str_num = new String[al.Count];                 str_num = (string[])al.ToArray(typeof(string));                 for (int k = 0; k < str_num.Length; k++) {                     Response.Write(str_num[k]);                     Response.Write("，");                 }