二維碼是用某種特定的幾何圖形按一定規律在平面（二維方向上）分布的黑白相間的圖形記錄資料符号資訊的，國外對二維碼技術的研究始于20世紀80年代末，在二維碼符号表示技術研究方面已研制出多種碼制，常見的有PDF417、QR Code、Code 49、Code 16K、Code One等。二維碼技術已經被廣泛應用于公安、外交、軍事等部門對各類證件的管理，而且也将二維碼應用于海關、稅務等部門對各類報表和票據的管理，商業、交通運輸等部門對商品及貨物運輸的管理、郵政部門對郵政包裹的管理、工業生産領域對工業生産線的自動化管理。
下面介紹一下如何用.NET生成二維碼（QR Code碼制），下面給出詳細步驟：
1 項目結構
建立一個window應用程式，然後引入.NET二維碼類庫（開源的類庫，可從網上下載下傳）：
2 代碼實作
在Form1視窗上進行UI設計，可以通過拖拽方式建構UI界面，界面上有一個文本框，可以輸入資訊，如網址資訊，右側有一個編碼按鈕，用于生成二維碼，下面是具體的代碼：
namespace WinQRCode
{
partial class Form1
{
/// <summary>
/// 必需的設計器變量。
/// </summary>
private System.ComponentModel.IContainer components = null;
/// <summary>
/// 清理所有正在使用的資源。
/// </summary>
/// <param name="disposing">如果應釋放托管資源，為 true；否則為 false。</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows 窗體設計器生成的代碼
/// <summary>
/// 設計器支援所需的方法 - 不要
/// 使用代碼編輯器修改此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.button1 = new System.Windows.Forms.Button();
this.button2 = new System.Windows.Forms.Button();
this.pictureBox1 = new System.Windows.Forms.PictureBox();
this.label1 = new System.Windows.Forms.Label();
this.textBox1 = new System.Windows.Forms.TextBox();
this.label2 = new System.Windows.Forms.Label();
this.lbl解碼資訊 = new System.Windows.Forms.Label();
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
this.SuspendLayout();
//
// button1
//
this.button1.Location = new System.Drawing.Point(446, 31);
this.button1.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(103, 37);
this.button1.TabIndex = 0;
this.button1.Text = "編碼";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// button2
//
this.button2.Location = new System.Drawing.Point(446, 81);
this.button2.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
this.button2.Name = "button2";
this.button2.Size = new System.Drawing.Size(103, 37);
this.button2.TabIndex = 1;
this.button2.Text = "解碼";
this.button2.UseVisualStyleBackColor = true;
this.button2.Click += new System.EventHandler(this.button2_Click);
//
// pictureBox1
//
this.pictureBox1.Location = new System.Drawing.Point(23, 117);
this.pictureBox1.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.Size = new System.Drawing.Size(279, 253);
this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
this.pictureBox1.TabIndex = 2;
this.pictureBox1.TabStop = false;
//
// label1
//
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(18, 39);
this.label1.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(69, 25);
this.label1.TabIndex = 3;
this.label1.Text = "資訊：";
//
// textBox1
//
this.textBox1.Location = new System.Drawing.Point(95, 37);
this.textBox1.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
this.textBox1.Name = "textBox1";
this.textBox1.Size = new System.Drawing.Size(333, 31);
this.textBox1.TabIndex = 4;
//
// label2
//
this.label2.AutoSize = true;
this.label2.Location = new System.Drawing.Point(18, 81);
this.label2.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
this.label2.Name = "label2";
this.label2.Size = new System.Drawing.Size(88, 25);
this.label2.TabIndex = 5;
this.label2.Text = "二維碼：";
//
// lbl解碼資訊
//
this.lbl解碼資訊.AutoSize = true;
this.lbl解碼資訊.Location = new System.Drawing.Point(101, 81);
this.lbl解碼資訊.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
this.lbl解碼資訊.Name = "lbl解碼資訊";
this.lbl解碼資訊.Size = new System.Drawing.Size(0, 25);
this.lbl解碼資訊.TabIndex = 6;
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(11F, 24F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(572, 384);
this.Controls.Add(this.lbl解碼資訊);
this.Controls.Add(this.label2);
this.Controls.Add(this.textBox1);
this.Controls.Add(this.label1);
this.Controls.Add(this.pictureBox1);
this.Controls.Add(this.button2);
this.Controls.Add(this.button1);
this.Font = new System.Drawing.Font("微軟雅黑", 10.8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
this.Margin = new System.Windows.Forms.Padding(4, 5, 4, 5);
this.Name = "Form1";
this.Text = "二維碼";
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.Label label2;
private System.Windows.Forms.Label lbl解碼資訊;
}
} UI界面顯示如下所示：
而UI界面上的事件代碼，需要修改背景代碼進行實作，其中的編碼和解碼按鈕事件的核心代碼如下：
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 WinQRCode
{
using ThoughtWorks.QRCode.Codec;
using ThoughtWorks.QRCode.Codec.Data;
using ThoughtWorks.QRCode.Codec.Util;
using System.IO;
using PdfToImage;
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
/// <summary>
/// 編碼
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button1_Click(object sender, EventArgs e)
{
if (this.textBox1.Text != "")
{
Cursor.Current = Cursors.WaitCursor;
if (textBox1.Text.Trim() == String.Empty)
{
MessageBox.Show("不能為空.");
return;
}
QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
qrCodeEncoder.QRCodeScale = 4;
qrCodeEncoder.QRCodeVersion = 7;
qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
System.Drawing.Image image;
String data = textBox1.Text;
//編碼
image = qrCodeEncoder.Encode(data);
//圖檔顯示
this.pictureBox1.Image = image;
Cursor.Current = Cursors.Default;
}
}
/// <summary>
/// 解碼
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button2_Click(object sender, EventArgs e)
{
Cursor.Current = Cursors.WaitCursor;
Bitmap b = this.pictureBox1.Image as Bitmap;
try
{
QRCodeDecoder decoder = new QRCodeDecoder();
//解碼
String decodedString = decoder.decode(new QRCodeBitmapImage(b));
//顯示解碼資訊
this.lbl解碼資訊.Text += decodedString ;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
Cursor.Current = Cursors.Default;
}
private void Form1_Load(object sender, EventArgs e)
{
}
}
} 首先需要引入相關的二維碼庫檔案中的命名空間，然後從UI上擷取文本框資訊，調用庫檔案中的編碼和解碼方法即可。QRCodeEncoder類中的 Encode(data)方法生成一個image對象，并指派到pictureBox1控件上進行顯示即可。
3 效果
編譯運作，示範程式顯示如下圖所示：