List<>泛型排序，快速去重复

public int IsHasMail(string mail, string reg_id)
{
//此方法用户在认证邮箱时检测
//所分情况
//1、该邮箱已经有人使用
//2、自己的邮箱重复认证
//3、该邮箱可以认证
//声明返回变量
int retdata = 0;
List<Model.UserCheck> lmuc = new List<Model.UserCheck>();
lmuc = GetModelList("value = '" + HttpUtility.UrlDecode(mail) + "' ");
if (lmuc.Count > 0)
{
//进行排序
lmuc.Sort(delegate(Model.UserCheck modelp1, Model.UserCheck modelp2)
{
return Comparer<string>.Default.Compare(modelp1.Value, modelp2.Value);
});
//去除重复的值
List<Model.UserCheck> lmuc1 = new List<Model.UserCheck>();
for (int i = 0; i < lmuc.Count; i++)
{
Model.UserCheck model = new Model.UserCheck();
model = lmuc[i];
if (lmuc[i].Value == lmuc[i + 1].Value)
{
continue;
}
lmuc1.Add(model);
}
}
return retdata;
}