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 项目结构
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 代码实现
在Form1窗口上进行UI设计，可以通过拖拽方式构建UI界面，界面上有一个文本框，可以输入信息，如网址信息，右侧有一个编码按钮，用于生成二维码，下面是具体的代码：
namespaceWinQRCode{ partialclassForm1 { /// <summary>/// 必需的设计器变量。/// </summary>privateSystem.ComponentModel.IContainercomponents=null; /// <summary>/// 清理所有正在使用的资源。/// </summary>/// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>protectedoverridevoidDispose(booldisposing) { if (disposing&& (components!=null)) { components.Dispose(); } base.Dispose(disposing); } #regionWindows窗体设计器生成的代码/// <summary>/// 设计器支持所需的方法 - 不要/// 使用代码编辑器修改此方法的内容。/// </summary>privatevoidInitializeComponent() { this.button1=newSystem.Windows.Forms.Button(); this.button2=newSystem.Windows.Forms.Button(); this.pictureBox1=newSystem.Windows.Forms.PictureBox(); this.label1=newSystem.Windows.Forms.Label(); this.textBox1=newSystem.Windows.Forms.TextBox(); this.label2=newSystem.Windows.Forms.Label(); this.lbl解码信息=newSystem.Windows.Forms.Label(); ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit(); this.SuspendLayout(); //// button1//this.button1.Location=newSystem.Drawing.Point(446, 31); this.button1.Margin=newSystem.Windows.Forms.Padding(4, 5, 4, 5); this.button1.Name="button1"; this.button1.Size=newSystem.Drawing.Size(103, 37); this.button1.TabIndex=0; this.button1.Text="编码"; this.button1.UseVisualStyleBackColor=true; this.button1.Click+=newSystem.EventHandler(this.button1_Click); //// button2//this.button2.Location=newSystem.Drawing.Point(446, 81); this.button2.Margin=newSystem.Windows.Forms.Padding(4, 5, 4, 5); this.button2.Name="button2"; this.button2.Size=newSystem.Drawing.Size(103, 37); this.button2.TabIndex=1; this.button2.Text="解码"; this.button2.UseVisualStyleBackColor=true; this.button2.Click+=newSystem.EventHandler(this.button2_Click); //// pictureBox1//this.pictureBox1.Location=newSystem.Drawing.Point(23, 117); this.pictureBox1.Margin=newSystem.Windows.Forms.Padding(4, 5, 4, 5); this.pictureBox1.Name="pictureBox1"; this.pictureBox1.Size=newSystem.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=newSystem.Drawing.Point(18, 39); this.label1.Margin=newSystem.Windows.Forms.Padding(4, 0, 4, 0); this.label1.Name="label1"; this.label1.Size=newSystem.Drawing.Size(69, 25); this.label1.TabIndex=3; this.label1.Text="信息："; //// textBox1//this.textBox1.Location=newSystem.Drawing.Point(95, 37); this.textBox1.Margin=newSystem.Windows.Forms.Padding(4, 5, 4, 5); this.textBox1.Name="textBox1"; this.textBox1.Size=newSystem.Drawing.Size(333, 31); this.textBox1.TabIndex=4; //// label2//this.label2.AutoSize=true; this.label2.Location=newSystem.Drawing.Point(18, 81); this.label2.Margin=newSystem.Windows.Forms.Padding(4, 0, 4, 0); this.label2.Name="label2"; this.label2.Size=newSystem.Drawing.Size(88, 25); this.label2.TabIndex=5; this.label2.Text="二维码："; //// lbl解码信息//this.lbl解码信息.AutoSize=true; this.lbl解码信息.Location=newSystem.Drawing.Point(101, 81); this.lbl解码信息.Margin=newSystem.Windows.Forms.Padding(4, 0, 4, 0); this.lbl解码信息.Name="lbl解码信息"; this.lbl解码信息.Size=newSystem.Drawing.Size(0, 25); this.lbl解码信息.TabIndex=6; //// Form1//this.AutoScaleDimensions=newSystem.Drawing.SizeF(11F, 24F); this.AutoScaleMode=System.Windows.Forms.AutoScaleMode.Font; this.ClientSize=newSystem.Drawing.Size(572, 384); this.Controls.Add(this.lbl解码信息); 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=newSystem.Drawing.Font("微软雅黑", 10.8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134))); this.Margin=newSystem.Windows.Forms.Padding(4, 5, 4, 5); this.Name="Form1"; this.Text="二维码"; ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit(); this.ResumeLayout(false); this.PerformLayout(); } #endregionprivateSystem.Windows.Forms.Buttonbutton1; privateSystem.Windows.Forms.Buttonbutton2; privateSystem.Windows.Forms.PictureBoxpictureBox1; privateSystem.Windows.Forms.Labellabel1; privateSystem.Windows.Forms.TextBoxtextBox1; privateSystem.Windows.Forms.Labellabel2; privateSystem.Windows.Forms.Labellbl解码信息; } }
UI界面显示如下所示：
而UI界面上的事件代码，需要修改后台代码进行实现，其中的编码和解码按钮事件的核心代码如下：
usingSystem; usingSystem.Collections.Generic; usingSystem.ComponentModel; usingSystem.Data; usingSystem.Drawing; usingSystem.Linq; usingSystem.Text; usingSystem.Windows.Forms; namespaceWinQRCode{ usingThoughtWorks.QRCode.Codec; usingThoughtWorks.QRCode.Codec.Data; usingThoughtWorks.QRCode.Codec.Util; usingSystem.IO; usingPdfToImage; publicpartialclassForm1 : Form { publicForm1() { InitializeComponent(); } /// <summary>/// 编码/// </summary>/// <param name="sender"></param>/// <param name="e"></param>privatevoidbutton1_Click(objectsender, EventArgse) { if (this.textBox1.Text!="") { Cursor.Current=Cursors.WaitCursor; if (textBox1.Text.Trim() ==String.Empty) { MessageBox.Show("不能为空."); return; } QRCodeEncoderqrCodeEncoder=newQRCodeEncoder(); qrCodeEncoder.QRCodeEncodeMode=QRCodeEncoder.ENCODE_MODE.BYTE; qrCodeEncoder.QRCodeScale=4; qrCodeEncoder.QRCodeVersion=7; qrCodeEncoder.QRCodeErrorCorrect=QRCodeEncoder.ERROR_CORRECTION.M; System.Drawing.Imageimage; Stringdata=textBox1.Text; //编码image=qrCodeEncoder.Encode(data); //图片显示this.pictureBox1.Image=image; Cursor.Current=Cursors.Default; } } /// <summary>/// 解码/// </summary>/// <param name="sender"></param>/// <param name="e"></param>privatevoidbutton2_Click(objectsender, EventArgse) { Cursor.Current=Cursors.WaitCursor; Bitmapb=this.pictureBox1.ImageasBitmap; try { QRCodeDecoderdecoder=newQRCodeDecoder(); //解码StringdecodedString=decoder.decode(newQRCodeBitmapImage(b)); //显示解码信息this.lbl解码信息.Text+=decodedString ; } catch (Exceptionex) { MessageBox.Show(ex.Message); } Cursor.Current=Cursors.Default; } privatevoidForm1_Load(objectsender, EventArgse) { } } }
首先需要引入相关的二维码库文件中的命名空间，然后从UI上获取文本框信息，调用库文件中的编码和解码方法即可。QRCodeEncoder类中的 Encode(data)方法生成一个image对象，并赋值到pictureBox1控件上进行显示即可。
3 效果
编译运行，演示程序显示如下图所示：
