基于C#动态生成带参数的小程序二维码

<div class="user-box">
            <span>验证手机</span><br>
            <br>
            <div class="query-box">
                <label>
                    扫描二维码获取动态校验码</label>
                <br>
                <label>
                    建议您PC注册,如果微信,可常按并选择前往图中包含的小程序打开(某些手机系统可能不支持此操作)</label></div>
            <br>
            <br>
            <asp:Button ID="createCode" Text="新注册或换手机号点这里生成以获取动态校验码" Visible="true" CssClass="form-control"
                runat="server" OnClick="createCode_Click"></asp:Button>
        </div>
        <div class="user-box" id="ecodepanel" align="center" visible="false" runat="server">
            <br />
            <asp:Image ID="ecode" Width="200px" Height="200px" Visible="false" runat="server"></asp:Image>
            <br>
            <span style='color: silver'></span>
            <br>
            <br>
        </div>

protected void createCode_Click(object sender, EventArgs e)
    {
        string paras = "reqvmobile";    //参数值设置
                //可以更改小程序二维码的色系
        int r = 4;
        int g = 128;
        int b = 188;
        ecode.ImageUrl = getBase64(255, r, g, b);   //将生成成功的BASE64编码赋值给Image控件
        ecode.Visible = true;
        ecodepanel.Visible = true;
    }
    //获取小程序二维码图片的 Base64值 
    string getBase64(string paras, int width, int linecolor_R, int linecolor_G, int linecolor_B)
    {
        string desimg = Request.PhysicalApplicationPath + "\\app_data\\" + System.Guid.NewGuid().ToString() + ".jpg";  //目标图片临时路径
                //生成二维码图片文件
        System.IO.File.WriteAllBytes(desimg, getMpBuffer(wxmp_accesstoken, paras, width, linecolor_R, linecolor_G, linecolor_B));
        string base64 = ImgToBase64String(desimg, true);
        System.IO.File.Delete(desimg);  //删除临时文件
        return base64;
    }
 
//图片转BASE64方法
public string ImgToBase64String(string Imagefilename,bool outFullString=false)
            {
                try
                {
                    System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(Imagefilename);
 
                    MemoryStream ms = new MemoryStream();
                    //            bmp.Save(ms,ImageFormat.Jpeg)
                    System.Drawing.Imaging.ImageFormat iformat = System.Drawing.Imaging.ImageFormat.Jpeg;
                    string extension = System.IO.Path.GetExtension(Imagefilename).Replace(".", "").ToLower();
                    if (extension == "bmp")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Bmp;
                    }
                    else if (extension == "emf")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Emf;
                    }
                    else if (extension == "exif")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Exif;
                    }
                    else if (extension == "gif")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Gif;
                    }
                    else if (extension == "icon")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Icon;
                    }
                    else if (extension == "png")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Png;
                    }
                    else if (extension == "tiff")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Tiff;
                    }
                    else if (extension == "wmf")
                    {
                        iformat = System.Drawing.Imaging.ImageFormat.Wmf;
                    }
 
                    bmp.Save(ms, iformat);
                    byte[] arr = new byte[ms.Length];
                    ms.Position = 0;
                    ms.Read(arr, 0, (int)ms.Length);
                    ms.Close();
                    bmp.Dispose();
                    string rv=Convert.ToBase64String(arr);
                    if (outFullString == true)
                    {
                        rv = "data:image/" + extension + ";base64," + rv;
                    }
                    return rv;
                }
                catch (Exception ex)
                {
                    return null;
                }
            }

public byte[] getMpBuffer(string access_token, string scene, int width, int linecolor_R, int linecolor_G, int linecolor_B)
        {
            var url = string.Format("https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token={0}", access_token);
            var postData = "{\"scene\":\"" + scene + "\",\"width\":" + width.ToString() + ",\"line_color\":{\"r\":" + linecolor_R.ToString() + ",\"g\":" + linecolor_G.ToString() + ",\"b\":" + linecolor_B.ToString() + "}}";
            
            System.Net.HttpWebRequest request;
            request = (System.Net.HttpWebRequest)WebRequest.Create(url);
            request.Method = "POST";
            request.ContentType = "application/json;charset=UTF-8";
            byte[] payload;
            payload = System.Text.Encoding.UTF8.GetBytes(postData);
            request.ContentLength = payload.Length;
            Stream writer = request.GetRequestStream();
            writer.Write(payload, 0, payload.Length);
            writer.Close();
            System.Net.HttpWebResponse response;
            response = (System.Net.HttpWebResponse)request.GetResponse();
            System.IO.Stream stream;
            stream = response.GetResponseStream();
            List<byte> bytes = new List<byte>();
            int temp = stream.ReadByte();
            while (temp != -1)
            {
                bytes.Add((byte)temp);
                temp = stream.ReadByte();
            }
            byte[] result = bytes.ToArray();
            return result;
        }