.net 合并两个数组为一个新的数组，两数组中相同的数据只存在一个

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections;

public partial class _Default : System.Web.UI.Page
{
void Page_Load() void Page_Load(object sender, EventArgs e)
{
string str1 = "010&011&012&112&151";
string str2 = "010&011&012&112&151";
string[] user1 = str1.Split('&');
string[] user2 = str2.Split('&');

string[] user3 = MergeArray(user1, user2);

for (int i = 0; i < user3.Length; i++)
{
Response.Write(user3[i]+"<br>");
}

}

static string [] MergeArray() static string [] MergeArray(string [] a, string [] b)
{

ArrayList student = new ArrayList();
foreach (string s1 in a)
{
student.Add(s1);
}
foreach (string s2 in b)
{
bool flag = true;
for (int i = 0; i < a.Length; i++)
{
if(a[i]==s2)
{
flag = false;
break;
}
}
if (flag)
{
student.Add(s2);
}
}
string[] c1= (string[])student.ToArray(typeof(string));

return c1;
}

}