用写C#写的一个IP输入框控件

using System;
using System.Collections.Generic;
using System.Text;

namespace IpBox
{
    using System;
    using System.Collections;
    using System.ComponentModel;
    using System.Drawing;
    using System.Data;
    using System.Windows.Forms;
    using System.Text.RegularExpressions;

    public class IpBox : System.Windows.Forms.UserControl
    {
        private System.Windows.Forms.Panel panel1;
        private System.Windows.Forms.TextBox textBox4;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.TextBox textBox3;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.TextBox textBox2;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.TextBox textBox1;
        private string _text = "";
        
        private System.ComponentModel.Container components = null;

        public IpBox()
        {
            // 该调用是 Windows.Forms 窗体设计器所必需的。
            InitializeComponent();

            // TODO: 在 InitializeComponent 调用后添加任何初始化

        }

        
        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose(disposing);
        }

        #region 组件设计器生成的代码
     
        private void InitializeComponent()
        {
            this.panel1 = new System.Windows.Forms.Panel();
            this.textBox4 = new System.Windows.Forms.TextBox();
            this.label3 = new System.Windows.Forms.Label();
            this.textBox3 = new System.Windows.Forms.TextBox();
            this.label2 = new System.Windows.Forms.Label();
            this.textBox2 = new System.Windows.Forms.TextBox();
            this.label1 = new System.Windows.Forms.Label();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.panel1.SuspendLayout();
            this.SuspendLayout();
            // 
            // panel1
            // 
            this.panel1.BackColor = System.Drawing.Color.White;
            this.panel1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
            this.panel1.Controls.Add(this.textBox4);
            this.panel1.Controls.Add(this.label3);
            this.panel1.Controls.Add(this.textBox3);
            this.panel1.Controls.Add(this.label2);
            this.panel1.Controls.Add(this.textBox2);
            this.panel1.Controls.Add(this.label1);
            this.panel1.Controls.Add(this.textBox1);
            this.panel1.Location = new System.Drawing.Point(0, 0);
            this.panel1.Name = "panel1";
            this.panel1.Size = new System.Drawing.Size(136, 20);
            this.panel1.TabIndex = 1;
            // 
            // textBox4
            // 
            this.textBox4.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.textBox4.Location = new System.Drawing.Point(104, 0);
            this.textBox4.MaxLength = 3;
            this.textBox4.Name = "textBox4";
            this.textBox4.Size = new System.Drawing.Size(20, 14);
            this.textBox4.TabIndex = 6;
            this.textBox4.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
            this.textBox4.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.textBox4_KeyPress);
            // 
            // label3
            // 
            this.label3.Location = new System.Drawing.Point(96, 0);
            this.label3.Name = "label3";
            this.label3.Size = new System.Drawing.Size(8, 14);
            this.label3.TabIndex = 5;
            this.label3.Text = ".";
            this.label3.TextAlign = System.Drawing.ContentAlignment.TopCenter;
            // 
            // textBox3
            // 
            this.textBox3.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.textBox3.Location = new System.Drawing.Point(72, 0);
            this.textBox3.MaxLength = 3;
            this.textBox3.Name = "textBox3";
            this.textBox3.Size = new System.Drawing.Size(20, 14);
            this.textBox3.TabIndex = 4;
            this.textBox3.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
            this.textBox3.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.textBox3_KeyPress);
            // 
            // label2
            // 
            this.label2.Location = new System.Drawing.Point(64, 0);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(8, 14);
            this.label2.TabIndex = 3;
            this.label2.Text = ".";
            this.label2.TextAlign = System.Drawing.ContentAlignment.TopCenter;
            // 
            // textBox2
            // 
            this.textBox2.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.textBox2.Location = new System.Drawing.Point(40, 0);
            this.textBox2.MaxLength = 3;
            this.textBox2.Name = "textBox2";
            this.textBox2.Size = new System.Drawing.Size(20, 14);
            this.textBox2.TabIndex = 2;
            this.textBox2.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
            this.textBox2.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.textBox2_KeyPress);
            // 
            // label1
            // 
            this.label1.Location = new System.Drawing.Point(32, 0);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(8, 14);
            this.label1.TabIndex = 1;
            this.label1.Text = ".";
            this.label1.TextAlign = System.Drawing.ContentAlignment.TopCenter;
            // 
            // textBox1
            // 
            this.textBox1.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.textBox1.Location = new System.Drawing.Point(8, 0);
            this.textBox1.MaxLength = 3;
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(20, 14);
            this.textBox1.TabIndex = 0;
            this.textBox1.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
            this.textBox1.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.textBox1_KeyPress);
            // 
            // IpBox
            // 
            this.Controls.Add(this.panel1);
            this.Name = "IpBox";
            this.Size = new System.Drawing.Size(136, 20);
            this.panel1.ResumeLayout(false);
            this.panel1.PerformLayout();
            this.ResumeLayout(false);

        }
        #endregion

        private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
        {
            //System.Text.Encoding.GetEncoding(0).GetString();
        }

        private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
        {
            MaskIpAddr(textBox1, e);
        }

        private void textBox2_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
        {
            MaskIpAddr(textBox2, e);
        }

        private void textBox3_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
        {
            MaskIpAddr(textBox3, e);
        }

        private void textBox4_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
        {
            MaskIpAddr(textBox4, e);
        }

        private void MaskIpAddr(System.Windows.Forms.TextBox textBox, KeyPressEventArgs e)
        {
            int len = textBox.Text.Length;

            if (Char.IsDigit(e.KeyChar) || e.KeyChar == '.' || e.KeyChar == 8)
            {
                if (e.KeyChar != 8)
                {
                    if (len == 2 && e.KeyChar != '.')
                    {
                        string tmp = textBox.Text + e.KeyChar;
                        if (textBox.Name == "textBox1")
                        {
                            if (Int32.Parse(tmp) > 223) // 进行验证
                            {
                                MessageBox.Show(tmp + " 不是一个有效项目。请指定一个介于 1 和 223 之间的数值。");
                                textBox.Text = "223";
                                textBox.Focus();
                                return;
                            }

                            textBox2.Focus();
                            textBox2.SelectAll();

                        }
                        else if (textBox.Name == "textBox2")
                        {
                            if (Int32.Parse(tmp) > 255)
                            {
                                MessageBox.Show(tmp + " 不是一个有效项目。请指定一个介于 1 和 255 之间的数值。");
                                textBox.Text = "255";
                                textBox.Focus();
                                return;
                            }
                            textBox3.Focus();
                            textBox3.SelectAll();
                        }
                        else if (textBox.Name == "textBox3")
                        {
                            if (Int32.Parse(tmp) > 255)
                            {
                                MessageBox.Show(tmp + " 不是一个有效项目。请指定一个介于 1 和 255 之间的数值。");
                                textBox.Text = "255";
                                textBox.Focus();
                                return;
                            }
                            textBox4.Focus();
                            textBox4.SelectAll();
                        }
                        else if (textBox.Name == "textBox4")
                        {
                            if (Int32.Parse(tmp) > 255)
                            {
                                MessageBox.Show(tmp + " 不是一个有效项目。请指定一个介于 1 和 255 之间的数值。");
                                textBox.Text = "255";
                                textBox.Focus();
                                return;
                            }

                        }

                    }
                    if (e.KeyChar == '.')
                    {
                        if (textBox.Name == "textBox1" && textBox.Text != "")
                        {
                            textBox2.Focus();
                            textBox2.SelectAll();
                        }
                        if (textBox.Name == "textBox2" && textBox.Text != "")
                        {
                            textBox3.Focus();
                            textBox3.SelectAll();
                        }
                        if (textBox.Name == "textBox3" && textBox.Text != "")
                        {
                            textBox4.Focus();
                            textBox4.SelectAll();
                        }
                        if (textBox.Name == "textBox4" && textBox.Text != "")
                        {

                        }
                        e.Handled = true;
                    }
                }
                else
                {
                    if (textBox.Name == "textBox1" && textBox.Text == "")
                    {

                    }
                    if (textBox.Name == "textBox2" && textBox.Text == "")
                    {
                        textBox1.Focus();
                        textBox1.SelectionStart = textBox1.Text.Length;
                    }
                    if (textBox.Name == "textBox3" && textBox.Text == "")
                    {
                        textBox2.Focus();
                        textBox2.SelectionStart = textBox2.Text.Length;
                    }
                    if (textBox.Name == "textBox4" && textBox.Text == "")
                    {
                        textBox3.Focus();
                        textBox3.SelectionStart = textBox3.Text.Length;
                    }
                    e.Handled = false;
                }
            }
            else
                e.Handled = true;
        }


        [Browsable(true)]
        
        // 获取 IpBox 的文本。
        
        public new string Text
        {
            get
            {
                if (textBox1.Text == ""
                 || textBox2.Text == ""
                 || textBox3.Text == ""
                 || textBox4.Text == "")
                {
                    _text = "";
                    return _text;
                }
                else
                {
                    _text = Convert.ToInt32(textBox1.Text).ToString() + "." + Convert.ToInt32(textBox2.Text).ToString() + "." + Convert.ToInt32(textBox3.Text).ToString() + "." + Convert.ToInt32(textBox4.Text).ToString();
                    return _text;
                }

            }
            /* set  // 
             {
              if(value != null)
              {
               // 255-255-255-255
               //string pattern = @"^([1-9]|/d{2}|1[0-9]{1,2}|2[0-5]{2})/.(/d{1,2}|1[0-9]{1,2}|[1-2][0-5]{2})/.(/d{1,2}|1[0-9]{1,2}|[1-2][0-5]{2})/.(/d{1,2}|1[0-9]{1,2}|[1-2][0-5]{2})$";
               // 223-255-255-255
               string pattern = @"^([1-9]|/d{2}|1[0-9]{1,2}|2[1-2][1-3])/.(/d{1,2}|1[0-9]{1,2}|[1-2][0-5]{2})/.(/d{1,2}|1[0-9]{1,2}|[1-2][0-5]{2})/.(/d{1,2}|1[0-9]{1,2}|[1-2][0-5]{2})$";

               if( !Regex.IsMatch(value , pattern) )
               {
                _text = "";
                throw new Exception("IP 地址格式错误！");
               }
               else
               {
                string[] ipnum = value.Split('.');
                textBox1.Text = ipnum[0];
                textBox2.Text = ipnum[1];
                textBox3.Text = ipnum[2];
                textBox4.Text = ipnum[3];
               }
              }

              _text = value;

             }
            */

        }

    }
}