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IP TextBox

, 8 Sep 2005
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An IP textbox control that mimics ip boxes in windows network settings


This simple IP address textbox replaces the lack of an IP box in Windows Forms control. Using the DLL you can just add the control to your toolbox and its use is very similar to a regular TextBox control.

Background (optional)

While writing an application for some end-users, i had the need for a textbox that only took an ip address and performed some validation to make sure the text entered was actually an IP. Since there was nothing readily availible that did what I wanted, I wrote a control that can easily be added to any .NET Windows Form.

Using the code

Using this control is very easy. Just right-click somewhere in your toolbox, then click "Add/Remove Items...". Now browse to the DLL, click OK and the control should now be in your toolbox. The control inherits the standard TextBox in Windows.Forms and overrides the Text property so that you can programmatically set or get the Text value as a string; I also added a method IsValid() which returns true if the Text property falls in the parameters of an actual IP address and false otherwise;

Points of Interest

The control is actually 4 TextBoxs and 3 Labels with "." placed at the appropriate locations. Most validation is done on KeyPress and currently a MessageBox pops up to alert the user of Invalid inputs such as numbers less than 0 or greater than 255.


No history yet, but thinking of being able to turn off the MessageBox warnings. There also is no validation when setting the Text programmatically and an unhandled exception is thrown.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Web Developer
United States United States
No Biography provided

Comments and Discussions

GeneralMy vote of 2 Pinmemberi0018-Jan-12 13:47 
GeneralMy vote of 5 PinmemberDonaldKnuth29-Oct-11 23:45 
GeneralNeed PinmemberHardikasd25-Feb-10 2:23 
GeneralNice PinmemberMember 33287121-Dec-09 1:59 
GeneralNew code update Pinmembersysx19-Nov-09 8:33 
QuestionRegarding IP textbox Pinmemberrajionline20-Sep-07 18:55 
GeneralCheck IP Textbox if it's filled with a ip address PinmemberLuneto_HA20-Mar-07 4:38 
GeneralRe: Check IP Textbox if it's filled with a ip address Pinmemberavramik14-Jun-10 21:20 
GeneralDataBinding Pinmemberjoelthegeek1-Dec-05 6:31 
GeneralMovement needs to be a little better Pinmemberluniv04048-Nov-05 10:26 
GeneralRe: Movement needs to be a little better Pinmemberjoelthegeek1-Dec-05 4:32 
GeneralNice Control ! A little question :doh: PinmemberFredyAlfredo20-Sep-05 3:25 
GeneralRe: Nice Control ! A little question :doh: Pinmembermawnkay27-Sep-05 5:16 
AnswerRe: Nice Control ! A little question :doh: Pinmembermawnkay4-Oct-05 5:44 
GeneralLittle changes PinmemberMansonP15-Sep-05 3:48 
GeneralRe: Little changes Pinmembermawnkay27-Sep-05 5:21 
GeneralRe: Little changes Pinmemberpinquotriot19-Mar-09 13:27 
General2 comments: PinmemberMadHatter ¢8-Sep-05 10:33 
1. put up pictures
2. you can wrap the standard IP Address control w/ much less code (this is a quick & dirty wrapper. I have a much better implementation, but this is just from memory):
namespace NullFX.Controls	{
    using System;
    using System.Net;
    using System.Windows.Forms;
    using System.Runtime.InteropServices;
    public struct Nmhdr	{
        public IntPtr HWndFrom;
        public int IdFrom;
        public int Code;
    public struct NmIPAddress {
        public Nmhdr Hdr;
        public int Field;
        public int Value;
    public enum	IPField	{OctetOne =	0,OctetTwo=1,OctetThree=2,OctetFour=3}
    public delegate	void TextChangedHandler(object sender, TextChangedEventArgs	e);
    public class TextChangedEventArgs :	EventArgs {
        private	int	_field,	_value;
        public int Field {
            get{return _field;}
        public int Value {
            get{return _value;}
        public TextChangedEventArgs(int	field, int value):base() {
            _field = field;
            _value = value;
    public class IPAddressControl : TextBox {
        private	const int WM_NOTIFY	= 0x004E,
            WM_USER	= 0x0400,
            WM_REFLECT = WM_USER + 0x1C00,
            IPM_SETRANGE = (WM_USER+103),
            IPM_GETADDRESS = (WM_USER+102),
            IPM_SETADDRESS = (WM_USER+101),
            IPM_CLEARADDRESS = (WM_USER+100),
            IPM_ISBLANK = (WM_USER+105);
        private	int[] values = new int[4];
        new	public event TextChangedHandler	TextChanged;
        public IPAddressControl() : base()	{
            for(int	i =	0; i < 4; i++)
                values[i] =	0;
        protected virtual void OnTextChanged(TextChangedEventArgs e) {
            if(TextChanged != null)	TextChanged(this, e);
        protected override CreateParams	CreateParams {
            get	{
                CreateParams cp	= base.CreateParams;
                cp.ClassName = "SysIPAddress32";
                cp.Height =	23;
                return cp;
        public bool	SetIPRange(IPField field, byte lowValue, byte highValue) {
            Message	m =	Message.Create(Handle, IPM_SETRANGE, (IntPtr)((int)field) ,	MakeRange(lowValue,	highValue));
            WndProc(ref	m);
            return m.Result.ToInt32() >	0;
        public System.Net.IPAddress IPAddress {
                return IPAddress.Parse(base.Text);
        public bool IsBlank {
                Message m = Message.Create(Handle, IPM_ISBLANK, IntPtr.Zero, IntPtr.Zero);
                WndProc(ref m);
                return m.Result.ToInt32() > 0;
        new public void Clear() {
            Message m = Message.Create(Handle, IPM_CLEARADDRESS, IntPtr.Zero, IntPtr.Zero);
            WndProc(ref m); 
        private System.Net.IPAddress GetIpAddress(IntPtr ip) {
            return new IPAddress(ip.ToInt64());
        private	IntPtr MakeRange(byte low, byte	high) {
            return (IntPtr)((int)((high	<< 8) +	low));
        protected override void	WndProc(ref	Message	m) {
            if(m.Msg ==	(WM_REFLECT	+ WM_NOTIFY)) {
                NmIPAddress	ipInfo =  (NmIPAddress)Marshal.PtrToStructure(m.LParam,	typeof(NmIPAddress));
                if(ipInfo.Hdr.Code == -860)	{
                    if(values[ipInfo.Field]	!= ipInfo.Value) {
                        values[ipInfo.Field] = ipInfo.Value;
                        OnTextChanged(new TextChangedEventArgs(ipInfo.Field, ipInfo.Value));
            base.WndProc (ref m);



GeneralRe: 2 comments: Pinmembermalharone8-Sep-05 16:23 
GeneralRe: 2 comments: PinmemberMadHatter ¢8-Sep-05 18:25 
GeneralRe: 2 comments: Pinmembermawnkay9-Sep-05 5:41 
GeneralRe: 2 comments: PinmemberMadHatter ¢9-Sep-05 8:33 

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