/// <summary>
/// Overrides the ConvertFrom method of IConvertFrom.
/// </summary>
/// <param name="source">the object to convert to an IPAddress</param>
/// <returns>the IPAddress</returns>
/// <remarks>
/// <para>
/// Uses the <see cref="IPAddress.Parse"/> method to convert the
/// <see cref="String"/> argument to an <see cref="IPAddress"/>.
/// If that fails then the string is resolved as a DNS hostname.
/// </para>
/// </remarks>
/// <exception cref="ConversionNotSupportedException">
/// The <paramref name="source"/> object cannot be converted to the
/// target type. To check for this condition use the <see cref="CanConvertFrom"/>
/// method.
/// </exception>
public object ConvertFrom(object source)
{
string str = source as string;
if (str != null && str.Length > 0)
{
try
{
#if NET_2_0 || NETCF_2_0
#if !NETCF_2_0
// Try an explicit parse of string representation of an IPAddress (v4 or v6)
IPAddress result;
if (IPAddress.TryParse(str, out result))
{
return(result);
}
#endif
// Try to resolve via DNS. This is a blocking call.
// GetHostEntry works with either an IPAddress string or a host name
IPHostEntry host = Dns.GetHostEntry(str);
if (host != null &&
host.AddressList != null &&
host.AddressList.Length > 0 &&
host.AddressList[0] != null)
{
return(host.AddressList[0]);
}
#else
// Before .NET 2 we need to try to parse the IPAddress from the string first
// Check if the string only contains IP address valid chars
if (str.Trim(validIpAddressChars).Length == 0)
{
try
{
// try to parse the string as an IP address
return(IPAddress.Parse(str));
}
catch (FormatException)
{
// Ignore a FormatException, try to resolve via DNS
}
}
// Try to resolve via DNS. This is a blocking call.
IPHostEntry host = Dns.GetHostByName(str);
if (host != null &&
host.AddressList != null &&
host.AddressList.Length > 0 &&
host.AddressList[0] != null)
{
return(host.AddressList[0]);
}
#endif
}
catch (Exception ex)
{
throw ConversionNotSupportedException.Create(typeof(IPAddress), source, ex);
}
}
throw ConversionNotSupportedException.Create(typeof(IPAddress), source);
}