从主机名创建ipendpoint

System.Net.Dns.GetHostAddresses

public static IPEndPoint GetIPEndPointFromHostName(string hostName, int port, bool throwIfMoreThanOneIP)
{
    var addresses = System.Net.Dns.GetHostAddresses(hostName);
    if (addresses.Length == 0)
    {
        throw new ArgumentException(
            "Unable to retrieve address from specified host name.", 
            "hostName"
        );
    }
    else if (throwIfMoreThanOneIP && addresses.Length > 1)
    {
        throw new ArgumentException(
            "There is more that one IP address to the specified host.", 
            "hostName"
        );
    }
    return new IPEndPoint(addresses[0], port); // Port gets validated here.
}

您可以使用如下内容:

var addresses = Dns.GetHostAddresses(uri);
Debug.Assert(addresses.Length > 0);
var endPoint = new IPEndPoint(addresses[0], port);