c# Network adapters list

Thursday, July 26, 2012 by Nate Bross

Someone asked on Stack Overflow:

I have code, which is using System.Net and System.Net.NetworkInformation references, it generates a list of my network connection names.

Everything seems fine and working, but when I made a class of this code, and exported values to listbox1 items add, I had only one network connection name, but really I have four.

How can I solve this problem?

private void button1_Click(object sender, EventArgs e)
{
    Adapters obj = new Adapters();
    var value = obj.net_adapters();
    listBox1.Items.Add(value);
}

public class Adapters
{
    public string net_adapters()
    {
        string value = string.Empty;
        foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
        {
            value = nic.Name;
        }
        return value;
    }
}

I posted the following answer, which was chosen as the accepted answer and received 17 upvotes:

I would modify the code you currently have:

public string net_adapters() 
{ 
    string value = string.Empty; 
    foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces()) 
    { 
        // bug in your original code right here is `=`
        // you proably meant to do something like value += ", " + nic.Name
        // which would not work well with listbox Items collection
        value = nic.Name; 
    } 
    return value; 
} 

To be like this:

public System.Collections.Generic.List<String> net_adapters() 
{ 
    List<String> values = new List<String>();
    foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces()) 
    { 
        values.Add(nic.Name);
    } 
    return values; 
}

A more fancy way (although it probably doesn’t matter because GetAllNetworkIntefaces probably blocks until it has has a full list) would be to use IEnumerable<T> and yield return:

public IEnumerable<String> net_adapters() 
{ 
    foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces()) 
    { 
        yield return nic.Name;
    } 
    yield break;
}

Either way, you would use it like this:

var obj = new Adapters();    
var values = obj.net_adapters();
listBox1.ItemsSource = values;

(On a side note, I would recommend that you use the .NET Framework Naming Guide)

Originally posted on Stack Overflow — 17 upvotes (accepted answer). Licensed under CC BY-SA.