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) { } }}