public List<string> names = new List<string>();

while(reader.Read())
{
    string name = reader["FirstName"].ToString().ToUpper());
    if (!names.Contains(name))
        names.Add(names);
    else
    {
        // handle reporting the duplicate here
    }
}

如果列表很大，那么考虑使用Dictionary或HashSet而不是List来提高性能。



如果你只需要一个列表那些没有重复的名字

If the list is large, then consider using a Dictionary or a HashSet instead of a List to improve performance.

If all you need is a list of the names with no duplicates then

public List<string> names = new List<string>();

while(reader.Read())
{
    string name = reader["FirstName"].ToString().ToUpper());
    names.Add(names);
    names = names.Distinct().ToList();
}

这个或类似的东西应该适合：

This or something similar should suit:

public List<string> names = new List<string>();

while (reader.Read())
{
    string name = reader["FirstName"].ToString().ToUpper());
    if (names.Count == 0)
    {
        names.Add(name);
    }
    else
    {
        bool duplicate;

        foreach (string n in names)
        {
            if (n == name)
                duplicate = true;
        }

        if (!duplicate)
            names.Add(name);
    }
}

如果列表为空，那么你总是添加字符串，然后每次你如果列表中不存在，则只读取您添加的名称。这样你就永远不会产生一个带有重复的列表。



如果这不是你想要的那么我恐怕我误解了你的要求。



祝你好运。 ：）

Here you are always adding the string if the list is empty, then each time you read a name you are only adding it if it does not exist in the list. This way you will never produce a list with duplicates in it.

If this is not what you want then I'm afraid I have misunderstood your request.

Good luck. :)

根据您的评论，这是一个更新的解决方案：



在命名空间中创建一个类型，类似于：

Based on your comment, here is an updated solution:

Create a type in your namespace, similar to this:

struct Record
{
    public string Name;
    public string PhoneNumber;
}

然后在你的方法中，比较类型值：

Then in your method, compare the type values:

public List<Record> Records = new List<Record>();

while (reader.Read())
{
    string name = reader["FirstName"].ToString().ToUpper());
    string phoneNumber = reader["PhoneNumber"].ToString();
    Record r = new Record();

    if (names.Count == 0)
    {
        r.Name = name;
        r.PhoneNumber = phoneNumber;
        Records.Add(r);
    }
    else
    {
        bool duplicate;

        foreach (Record record in Records)
        {
            if (record.Name == name &&
                record.PhoneNumber == phoneNumber)
                duplicate = true;
        }

        if (!duplicate)
            Records.Add(r);
        else
        {
            // Use whatever means you see fit here to
            // ask the user if they wish to replce the
            // existing record
        }
    }
}