c# 生成二维码的示例

二维码是越来越流行了，很多地方都有可能是使用到。如果是静态的二维码还是比较好处理的，通过在线工具就可以直接生成一张二维码图片，比如：草料二维码。但有的时候是需要动态生成的（根据动态数据生成），这个使用在线就工具就无法实现了。最好是能在代码中直接生成一个二维码图片，这里我就介绍下使用QRCoder类库在代码中生成二维码。

网上生成二维码的组件还是挺多的，但是真正好用且快速的却不多。QRCoder就是我在众多中找到的，它的生成速度快、而且使用也相当方便。

开始编码

1、安装 QRCoder组件。在项目上通过NuGet包管理器来安装，搜索名称：QRCoder

2、在代码中添加引用：using QRCoder;

3、编码生成

 private void RenderQrCode()
    {
      string level = comboBoxECC.SelectedItem.ToString();
      QRCodeGenerator.ECCLevel eccLevel = (QRCodeGenerator.ECCLevel)(level == "L" ? 0 : level == "M" ? 1 : level == "Q" ? 2 : 3);
      using (QRCodeGenerator qrGenerator = new QRCodeGenerator())
      {
        using (QRCodeData qrCodeData = qrGenerator.CreateQrCode(textBoxQRCode.Text, eccLevel))
        {
          using (QRCode qrCode = new QRCode(qrCodeData))
          {

            pictureBoxQRCode.BackgroundImage = qrCode.GetGraphic(20, Color.Black, Color.White,
              GetIconBitmap(), (int) iconSize.Value);

             this.pictureBoxQRCode.Size = new System.Drawing.Size(pictureBoxQRCode.Width, pictureBoxQRCode.Height);
            //Set the SizeMode to center the image.
            this.pictureBoxQRCode.SizeMode = PictureBoxSizeMode.CenterImage;

            pictureBoxQRCode.SizeMode = PictureBoxSizeMode.StretchImage;
          }
        }
      }
    }

上面代码运行的结果

还可以加上logo

 private Bitmap GetIconBitmap()
    {
      Bitmap img = null;
      if (iconPath.Text.Length > 0)
      {
        try
        {
          img = new Bitmap(iconPath.Text);
        }
        catch (Exception)
        {
        }
      }
      return img;
    }

完整代码

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;
using QRCoder;
using System.Drawing.Imaging;
using System.IO;

namespace QRCoderDemo
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
      comboBoxECC.SelectedIndex = 0; //Pre-select ECC level "L"
      RenderQrCode();
    }

    private void buttonGenerate_Click(object sender, EventArgs e)
    {
      RenderQrCode();
    }

    private void RenderQrCode()
    {
      string level = comboBoxECC.SelectedItem.ToString();
      QRCodeGenerator.ECCLevel eccLevel = (QRCodeGenerator.ECCLevel)(level == "L" ? 0 : level == "M" ? 1 : level == "Q" ? 2 : 3);
      using (QRCodeGenerator qrGenerator = new QRCodeGenerator())
      {
        using (QRCodeData qrCodeData = qrGenerator.CreateQrCode(textBoxQRCode.Text, eccLevel))
        {
          using (QRCode qrCode = new QRCode(qrCodeData))
          {

            pictureBoxQRCode.BackgroundImage = qrCode.GetGraphic(20, Color.Black, Color.White,
              GetIconBitmap(), (int) iconSize.Value);

             this.pictureBoxQRCode.Size = new System.Drawing.Size(pictureBoxQRCode.Width, pictureBoxQRCode.Height);
            //Set the SizeMode to center the image.
            this.pictureBoxQRCode.SizeMode = PictureBoxSizeMode.CenterImage;

            pictureBoxQRCode.SizeMode = PictureBoxSizeMode.StretchImage;
          }
        }
      }
    }

    private Bitmap GetIconBitmap()
    {
      Bitmap img = null;
      if (iconPath.Text.Length > 0)
      {
        try
        {
          img = new Bitmap(iconPath.Text);
        }
        catch (Exception)
        {
        }
      }
      return img;
    }

    private void selectIconBtn_Click(object sender, EventArgs e)
    {
      OpenFileDialog openFileDlg = new OpenFileDialog();
      openFileDlg.Title = "Select icon";
      openFileDlg.Multiselect = false;
      openFileDlg.CheckFileExists = true;
      if (openFileDlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
      {
        iconPath.Text = openFileDlg.FileName;
        if (iconSize.Value == 0)
        {
          iconSize.Value = 15;
        }
      }
      else
      {
        iconPath.Text = "";
      }
    }

    private void btn_save_Click(object sender, EventArgs e)
    {

      // Displays a SaveFileDialog so the user can save the Image
      SaveFileDialog saveFileDialog1 = new SaveFileDialog();
      saveFileDialog1.Filter = "Bitmap Image|*.bmp|PNG Image|*.png|JPeg Image|*.jpg|Gif Image|*.gif";
      saveFileDialog1.Title = "Save an Image File";
      saveFileDialog1.ShowDialog();

      // If the file name is not an empty string open it for saving.
      if (saveFileDialog1.FileName != "")
      {
        // Saves the Image via a FileStream created by the OpenFile method.
        using (FileStream fs = (System.IO.FileStream) saveFileDialog1.OpenFile())
        {
          // Saves the Image in the appropriate ImageFormat based upon the
          // File type selected in the dialog box.
          // NOTE that the FilterIndex property is one-based.

          ImageFormat imageFormat = null;
          switch (saveFileDialog1.FilterIndex)
          {
            case 1:
              imageFormat = ImageFormat.Bmp;
              break;
            case 2:
              imageFormat = ImageFormat.Png;
              break;
            case 3:
              imageFormat = ImageFormat.Jpeg;
              break;
            case 4:
              imageFormat = ImageFormat.Gif;
              break;
            default:
              throw new NotSupportedException("File extension is not supported");
          }

          pictureBoxQRCode.BackgroundImage.Save(fs, imageFormat);
          fs.Close();
        }
      }

    }

    public void ExportToBmp(string path)
    {

    }

    private void textBoxQRCode_TextChanged(object sender, EventArgs e)
    {
      RenderQrCode();
    }

    private void comboBoxECC_SelectedIndexChanged(object sender, EventArgs e)
    {
      RenderQrCode();
    }
  }
}

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