从List获取不同的属性值

I am trying to get distinct FullNames from a list that contains FullNames and IDs then displaying these in a listBox control. Is there a simple way to do it? Thanks Ben

我试图从包含FullNames和ID的列表中获取不同的FullNames，然后在listBox控件中显示这些。有一个简单的方法吗？谢谢本

using (DB2DataReader dr = command.ExecuteReader())
            {
                while (dr.Read())
                {

                Contact contact = new Contact();

                contact.ContactID = Convert.ToInt32(dr["CONTACT_ID"]);
                contact.FullName= dr["FULL_NAME"].ToString();


                myContacts.Add(contact);

                //contactsListBox.ItemsSource = myContacts.Distinct FullName??


            }
        }

2 个解决方案

#1

With LINQ:

使用LINQ：

var uniqueNames = myContacts.Select(c => c.FullName).Distinct().ToList();

should work. If the order is unimportant you could also use:

应该管用。如果订单不重要，您还可以使用：

var names = new HashSet<string>();
while(dr.Read()) {
    ...
    names.Add(contact.FullName);
}

(and then use ToList() / OrderBy whatever you need)

（然后使用ToList（）/ OrderBy，无论你需要什么）

#2

I think you can use different approaches here:

我想你可以在这里使用不同的方法：

Make Sql query that queries distinct values.

进行查询不同值的Sql查询。
Check that contact already in list. This approach assume that your class must redefine euqality operator. Or you can check that this contact id is already in list.

检查列表中的联系人。这种方法假设您的类必须重新定义euqality运算符。或者您可以检查此联系人ID是否已列在列表中。
Use Linq query as mentioned above.

如上所述使用Linq查询。

#1