二维码是用某种特定的几何图形按一定规律在平面（二维方向上）分布的黑白相间的图形记录数据符号信息的，国外对二维码技术的研究始于20世纪80年代末，在二维码符号表示技术研究方面已研制出多种码制，常见的有PDF417、QR Code、Code 49、Code 16K、Code One等。二维码技术已经被广泛应用于公安、外交、军事等部门对各类证件的管理，而且也将二维码应用于海关、税务等部门对各类报表和票据的管理，商业、交通运输等部门对商品及货物运输的管理、邮政部门对邮政包裹的管理、工业生产领域对工业生产线的自动化管理。
下面介绍一下如何用.NET生成二维码（QR Code码制），下面给出详细步骤：
1、新建一个window应用程序，然后引入.NET二维码类库（开源的类库，可从网上下载）：
2、构建UI界面，代码如下：
1 namespace WinQRCode
2 {
3 partial class Form1
4 {
5 /// <summary>
6 /// 必需的设计器变量。
7 /// </summary>
8 private System.ComponentModel.IContainer components = null;
9
10 /// <summary>
11 /// 清理所有正在使用的资源。
12 /// </summary>
13 /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
14 protected override void Dispose(bool disposing)
15 {
16 if (disposing && (components != null))
17 {
18 components.Dispose();
19 }
20 base.Dispose(disposing);
21 }
22
23 #region Windows 窗体设计器生成的代码
24
25 /// <summary>
26 /// 设计器支持所需的方法 - 不要
27 /// 使用代码编辑器修改此方法的内容。
28 /// </summary>
29 private void InitializeComponent()
30 {
31 this.button1 = new System.Windows.Forms.Button();
32 this.button2 = new System.Windows.Forms.Button();
33 this.pictureBox1 = new System.Windows.Forms.PictureBox();
34 this.label1 = new System.Windows.Forms.Label();
35 this.textBox1 = new System.Windows.Forms.TextBox();
36 this.label2 = new System.Windows.Forms.Label();
37 this.lbl解码信息 = new System.Windows.Forms.Label();
38 ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
39 this.SuspendLayout();
40 //
41 // button1
42 //
43 this.button1.Location = new System.Drawing.Point(446, 31);
44 this.button1.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
45 this.button1.Name = "button1";
46 this.button1.Size = new System.Drawing.Size(103, 37);
47 this.button1.TabIndex = 0;
48 this.button1.Text = "编码";
49 this.button1.UseVisualStyleBackColor = true;
50 this.button1.Click += new System.EventHandler(this.button1_Click);
51 //
52 // button2
53 //
54 this.button2.Location = new System.Drawing.Point(446, 81);
55 this.button2.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
56 this.button2.Name = "button2";
57 this.button2.Size = new System.Drawing.Size(103, 37);
58 this.button2.TabIndex = 1;
59 this.button2.Text = "解码";
60 this.button2.UseVisualStyleBackColor = true;
61 this.button2.Click += new System.EventHandler(this.button2_Click);
62 //
63 // pictureBox1
64 //
65 this.pictureBox1.Location = new System.Drawing.Point(23, 117);
66 this.pictureBox1.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
67 this.pictureBox1.Name = "pictureBox1";
68 this.pictureBox1.Size = new System.Drawing.Size(279, 253);
69 this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
70 this.pictureBox1.TabIndex = 2;
71 this.pictureBox1.TabStop = false;
72 //
73 // label1
74 //
75 this.label1.AutoSize = true;
76 this.label1.Location = new System.Drawing.Point(18, 39);
77 this.label1.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
78 this.label1.Name = "label1";
79 this.label1.Size = new System.Drawing.Size(69, 25);
80 this.label1.TabIndex = 3;
81 this.label1.Text = "信息：";
82 //
83 // textBox1
84 //
85 this.textBox1.Location = new System.Drawing.Point(95, 37);
86 this.textBox1.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
87 this.textBox1.Name = "textBox1";
88 this.textBox1.Size = new System.Drawing.Size(333, 31);
89 this.textBox1.TabIndex = 4;
90 //
91 // label2
92 //
93 this.label2.AutoSize = true;
94 this.label2.Location = new System.Drawing.Point(18, 81);
95 this.label2.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
96 this.label2.Name = "label2";
97 this.label2.Size = new System.Drawing.Size(88, 25);
98 this.label2.TabIndex = 5;
99 this.label2.Text = "二维码：";
100 //
101 // lbl解码信息
102 //
103 this.lbl解码信息.AutoSize = true;
104 this.lbl解码信息.Location = new System.Drawing.Point(101, 81);
105 this.lbl解码信息.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
106 this.lbl解码信息.Name = "lbl解码信息";
107 this.lbl解码信息.Size = new System.Drawing.Size(0, 25);
108 this.lbl解码信息.TabIndex = 6;
109 //
110 // Form1
111 //
112 this.AutoScaleDimensions = new System.Drawing.SizeF(11F, 24F);
113 this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
114 this.ClientSize = new System.Drawing.Size(572, 384);
115 this.Controls.Add(this.lbl解码信息);
116 this.Controls.Add(this.label2);
117 this.Controls.Add(this.textBox1);
118 this.Controls.Add(this.label1);
119 this.Controls.Add(this.pictureBox1);
120 this.Controls.Add(this.button2);
121 this.Controls.Add(this.button1);
122 this.Font = new System.Drawing.Font("微软雅黑", 10.8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
123 this.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
124 this.Name = "Form1";
125 this.Text = "二维码";
126 ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
127 this.ResumeLayout(false);
128 this.PerformLayout();
129
130 }
131
132 #endregion
133
134 private System.Windows.Forms.Button button1;
135 private System.Windows.Forms.Button button2;
136 private System.Windows.Forms.PictureBox pictureBox1;
137 private System.Windows.Forms.Label label1;
138 private System.Windows.Forms.TextBox textBox1;
139 private System.Windows.Forms.Label label2;
140 private System.Windows.Forms.Label lbl解码信息;
141 }
142 }
图形如下所示：
3、编写 编码和解码按钮事件，进行编码和解码处理：
1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Data;
5 using System.Drawing;
6 using System.Linq;
7 using System.Text;
8 using System.Windows.Forms;
9
10 namespace WinQRCode
11 {
12 using ThoughtWorks.QRCode.Codec;
13 using ThoughtWorks.QRCode.Codec.Data;
14 using ThoughtWorks.QRCode.Codec.Util;
15 using System.IO;
16 using PdfToImage;
17 public partial class Form1 : Form
18 {
19 public Form1()
20 {
21 InitializeComponent();
22 }
23 /// <summary>
24 /// 编码
25 /// </summary>
26 /// <param name="sender"></param>
27 /// <param name="e"></param>
28 private void button1_Click(object sender, EventArgs e)
29 {
30 if (this.textBox1.Text != "")
31 {
32 Cursor.Current = Cursors.WaitCursor;
33 if (textBox1.Text.Trim() == String.Empty)
34 {
35 MessageBox.Show("不能为空.");
36 return;
37 }
38 QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
39 qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
40 qrCodeEncoder.QRCodeScale = 4;
41 qrCodeEncoder.QRCodeVersion = 7;
42 qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
43 System.Drawing.Image image;
44 String data = textBox1.Text;
45 //编码
46 image = qrCodeEncoder.Encode(data);
47 //图片显示
48 this.pictureBox1.Image = image;
49 Cursor.Current = Cursors.Default;
50
51 }
52 }
53 /// <summary>
54 /// 解码
55 /// </summary>
56 /// <param name="sender"></param>
57 /// <param name="e"></param>
58 private void button2_Click(object sender, EventArgs e)
59 {
60 Cursor.Current = Cursors.WaitCursor;
61 Bitmap b = this.pictureBox1.Image as Bitmap;
62 try
63 {
64 QRCodeDecoder decoder = new QRCodeDecoder();
65 //解码
66 String decodedString = decoder.decode(new QRCodeBitmapImage(b));
67 //显示解码信息
68 this.lbl解码信息.Text += decodedString ;
69 }
70 catch (Exception ex)
71 {
72 MessageBox.Show(ex.Message);
73 }
74 Cursor.Current = Cursors.Default;
75 }
76
77 private void Form1_Load(object sender, EventArgs e)
78 {
79
80 }
81 }
82 }
4、编译运行，如下图：