C# 编写自定义 IP 输入框控件

场景: 做一些网络设备应用时，需要有ip地址的输入，这就需要ip地址输入框控件

思路:

1 重写TextBox 为IpInputBox。

2 重写TextBox为SubIpInputBox

3 一个IpInputBox 添加4个SubIpInputBox 和3个Label

控件图：

具体代码:

主窗口文件   Dialog.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace IP
{
    public delegate void FallBackEvent(IpInputBox box, int flag);

    public partial class Dialog : Form
    {
        public Dialog()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.Controls.Add(ipBox);
            ipBox.Location = new Point(10,10);
        }

        private IpInputBox ipBox = new IpInputBox(false);
    }
}

IpInputBox.cs 文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;

namespace IP
{
    public class IpInputBox :TextBox
    {
        private bool _isNetmask = false;
        public bool IsNetmask
        {
            get { return _isNetmask; }
            set { _isNetmask = value; }
        }
        public IpInputBox(bool isNetmask)
        {
            _isNetmask = isNetmask;

            this.Size = new System.Drawing.Size(150, 25);

            _dotLabel1.Text = ".";
            _dotLabel2.Text = ".";
            _dotLabel3.Text = ".";

            _dotLabel1.Size = new System.Drawing.Size(10, 25);
            _dotLabel2.Size = new System.Drawing.Size(10, 25);
            _dotLabel3.Size = new System.Drawing.Size(10, 25);

            _box1.IsNetmask = _isNetmask;
            _box2.IsNetmask = _isNetmask;
            _box3.IsNetmask = _isNetmask;
            _box4.IsNetmask = _isNetmask;

            _box1.Flag = 1;
            _box2.Flag = 2;
            _box3.Flag = 3;
            _box4.Flag = 4;

            this.Controls.Add(_box1);
            this.Controls.Add(_dotLabel1);

            this.Controls.Add(_box2);
            this.Controls.Add(_dotLabel2);

            this.Controls.Add(_box3);
            this.Controls.Add(_dotLabel3);

            this.Controls.Add(_box4);

            this.Font = new System.Drawing.Font(this.Font.Name, 11);
            _box1.Location = new System.Drawing.Point(-1, 2);
            _dotLabel1.Location = new System.Drawing.Point(29, 2);
            _box2.Location = new System.Drawing.Point(39, 2);
            _dotLabel2.Location = new System.Drawing.Point(69, 2);
            _box3.Location = new System.Drawing.Point(79, 2);
            _dotLabel3.Location = new System.Drawing.Point(109, 2);
            _box4.Location = new System.Drawing.Point(119, 2);

            _box1.Box = this;
            _box2.Box = this;
            _box3.Box = this;
            _box4.Box = this;
        }
        public void FallBackEventFun(IpInputBox box, int flag)
        {
            switch (flag)
            {
                case 1:
                    _box1.Focus();
                    break;
                case 2:
                    _box1.Focus();
                    break;
                case 3:
                    _box2.Focus(); ;
                    break;
                case 4:
                    _box3.Focus(); ;
                    break;
            }
        }

        private string _ipAddress = string.Empty;
        public void UpDateIpaddress()
        {
            try
            {
                string[] sArray = ipAddress.Split(new char[] { '.' });
                _box1.Text = sArray[0];
                _box2.Text = sArray[1];
                _box3.Text = sArray[2];
                _box4.Text = sArray[3];
            }
            catch (Exception exp)
            {
                MessageBox.Show("更新字符串失败:" + exp.Message);
            }
        }

        /// <summary>
        /// 获取ip地址
        /// </summary>
        public string IpAddressString
        {
            get
            {
                string _ipStr1 = _box1.Text;
                string _ipStr2 = _box2.Text;
                string _ipStr3 = _box3.Text;
                string _ipStr4 = _box4.Text;
                string _ipDotStr = ".";
                _ipAddress = _ipStr1 + _ipDotStr + _ipStr2 + _ipDotStr + _ipStr3 + _ipDotStr + _ipStr4;
                return _ipAddress;
            }
            set
            {
                _ipAddress = value;
            }
        }
        private string ipAddress = string.Empty;

        public string IpAddress
        {
            get { return ipAddress; }
            set { ipAddress = value; }
        }

        private SubIpInputBox _box1 = new SubIpInputBox("");
        private SubIpInputBox _box2 = new SubIpInputBox("");
        private SubIpInputBox _box3 = new SubIpInputBox("");
        private SubIpInputBox _box4 = new SubIpInputBox("");

        private Label _dotLabel1 = new Label();
        private Label _dotLabel2 = new Label();
        private Label _dotLabel3 = new Label();

    }
}

SubIpInputBox.cs 文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Windows.Forms;

namespace IP
{
    public class SubIpInputBox:TextBox
    {
            /// <summary>
            /// 判断是否是子网掩码,false表示ip地址,true表示子网掩码
            /// </summary>
            private bool _isNetmask = false;
            private bool _isSendKey = false;
            private System.ComponentModel.IContainer components;
            private int _flag = 0;

            public int Flag
            {
                get { return _flag; }
                set { _flag = value; }
            }

            /// <summary>
            ///
            /// </summary>
            public event FallBackEvent TextFallBackEvent;

            //定义事件函数
            public void FallBackEventFun(int flag)
            {
                if (TextFallBackEvent != null)
                {
                    TextFallBackEvent(box, this.Flag);
                }
            }

            public bool IsNetmask
            {
                get { return _isNetmask; }
                set { _isNetmask = value; }
            }

            /// <summary>
            /// 构造函数
            /// </summary>
            public SubIpInputBox(bool isNetmask)
            {
                _isNetmask = isNetmask;
                box = new IpInputBox(_isNetmask);
                this.Font = new System.Drawing.Font(this.Font.Name, 11);
                this.BorderStyle = System.Windows.Forms.BorderStyle.None;//去掉边框
                this.TextAlign = HorizontalAlignment.Center;//字体居中
                this.Size = new System.Drawing.Size(30, 25);
                this.MaxLength = 3;
            }

            public SubIpInputBox(string str)
            {
                this.Text = str;
                this.Size = new System.Drawing.Size(30, 25);
                this.MaxLength = 3;
                this.BorderStyle = System.Windows.Forms.BorderStyle.None;//去掉边框
                this.TextAlign = HorizontalAlignment.Center;//字体居中
            }

            private IpInputBox box;
            public IpInputBox Box
            {
                get { return box; }
                set { box = value; }
            }

            protected override void OnKeyUp(KeyEventArgs e)
            {
                base.OnKeyUp(e);

                if (this.Text == "")
                {
                    if (e.KeyCode.ToString() == "Back")
                    {
                        this.TextFallBackEvent += new FallBackEvent(box.FallBackEventFun);
                        this.FallBackEventFun(this.Flag);
                    }
                }
            }
            protected override void OnKeyPress(KeyPressEventArgs e)
            {
                base.OnKeyPress(e);

                //阻止从键盘输入键
                e.Handled = true;

                if ((e.KeyChar >= '0' && e.KeyChar <= '9') || (e.KeyChar == (char)8))
                {

                    if ((e.KeyChar == (char)8))
                    {
                        e.Handled = false; return;
                    }
                    else
                    {
                        int len = this.Text.Length;
                        if (len < 4)
                        {
                            if (len == 0 && e.KeyChar != '0')
                            {
                                e.Handled = false; return;
                            }
                            else if (len == 0)
                            {
                                if (this.Flag == 1 && this.IsNetmask == false)
                                {
                                    return;
                                }
                            }
                            e.Handled = false; return;
                        }
                        else
                        {
                            // MessageBox.Show("编号最多只能输入3位数字！");
                        }
                    }
                }
                else if (e.KeyChar == '.')
                {
                    //MessageBox.Show("编号只能输入数字！");
                    if (this.Text.Length != 0)
                    {
                        // 如果输入 . 就执行 TAB 键
                        SendKeys.SendWait("{TAB}");
                    }
                }
                else if (this._isSendKey)
                {
                    this.SelectAll();
                }

            }

            protected override void OnTextChanged(EventArgs e)
            {

                try
                {
                    string currentStr = this.Text;
                    int currentNumber = Convert.ToInt32(currentStr);
                    this.Text = currentNumber.ToString();
                    this.SelectionStart = currentStr.Length;//设置光标在末尾
                    if (_isNetmask == false)//表示ip地址
                    {

                        if (currentNumber > 223 || (currentNumber == 0 && this.Flag == 1))
                        {
                            MessageBox.Show("你输入的" + currentStr + "不是有效数值，请指定一个介于1到223之间的数值!", "错误", MessageBoxButtons.OK, MessageBoxIcon.Warning);

                            if (this.Flag == 1 && currentNumber == 0)
                            {
                                this.Text = "1";
                            }
                            else
                            {
                                this.Text = "223";
                            }
                            _isSendKey = true;
                            this.Focus();
                            this.SelectionStart = currentStr.Length;//设置光标在末尾
                            this.SelectAll();
                        }
                        else
                        {
                            if (currentStr.Length == 3 && _isSendKey == false)
                            {// 当输入的字符个数为3时，跳入另外一个输入框
                                //MessageBox.Show("输入完毕");
                                if (currentNumber == 0)
                                {
                                    this.Text = "";
                                    MessageBox.Show("000");
                                }
                                SendKeys.SendWait("{TAB}");
                            }
                        }

                    }
                    else//子网掩码
                    {
                        if (currentNumber > 255)
                        {
                            MessageBox.Show("你输入的" + currentStr + "不是有效数值，请指定一个介于0到255之间的数值!", "错误", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                            this.Text = "255";
                            this.Focus();
                            this.SelectionStart = currentStr.Length;//设置光标在末尾
                            this.SelectAll();
                        }
                        else
                        {
                            if (currentStr.Length == 3 && _isSendKey == false)
                            {// 当输入的字符个数为3时，跳入另外一个输入框
                                //MessageBox.Show("输入完毕");
                                SendKeys.SendWait("{TAB}");

                            }
                        }
                    }
                }
                catch
                {
                    // 异常处理
                }
            }

            private void InitializeComponent()
            {
                this.SuspendLayout();
                //
                // SubIpInputBox
                //
                this.TabIndexChanged += new System.EventHandler(this.SubTextBox_TabIndexChanged);
                this.ResumeLayout(false);
            }
            private void SubTextBox_TabIndexChanged(object sender, EventArgs e)
            {

            }
    }
}