在WPF中开启摄像头扫描二维码(Media+Zxing)

　　近两天项目中需要添加一个功能，是根据摄像头来读取二维码信息，然后根据读出来的信息来和数据库中进行对比显示数据。

　　选择技术zxing、wpfmediakit。基本的原理就是让wpfmediakit来对摄像头进行操作，然后zxing这个库对图片进行分析大致就是这样。

　　在后台中定义了定时器，用于解析当前摄像头的图像，然后直接读数据。

需要注意的是一定要引入 using wpfmediakit.directshow.controls; using zxing; 

public partial class yidong : page
    {
        public yidong()
        {
            initializecomponent();
            cb.itemssource = multimediautil.videoinputnames;//获得所有摄像头
            if (multimediautil.videoinputnames.length > 0)
            {
                cb.selectedindex = 0;//第0个摄像头为默认摄像头
            }
            else
            {
                messagebox.show("电脑没有安装任何可用摄像头");
            }
            cameratimer.isenabled = false;
            cameratimer.interval = new timespan(200); //执行间隔0.2秒
            cameratimer.tick += cameratimer_tick; ;
        }

        /// <summary>
        /// zxing 二维码扫描类
        /// </summary>
        barcodereader codereader = new barcodereader();

        /// <summary>
        /// 定时器
        /// </summary>
        dispatchertimer cameratimer = new dispatchertimer();

        private void cameratimer_tick(object sender, eventargs e)
        {
            rendertargetbitmap bmp = new rendertargetbitmap((int)vce.actualwidth, (int)vce.actualheight, 96, 96, pixelformats.default);
            vce.measure(vce.rendersize);
            vce.arrange(new rect(vce.rendersize));
            bmp.render(vce);
            bitmapencoder encoder = new jpegbitmapencoder();
            encoder.frames.add(bitmapframe.create(bmp));
            using (memorystream ms = new memorystream())
            {
                encoder.save(ms);
                bitmap btimap = new bitmap(ms);
                var result = codereader.decode(btimap);//解析条码
                if (result != null)
                {
                    string shelve_index = result.tostring();
                    observablecollection<xmodel.store_detailvm> list = xdal.store_goods_detail.getgoodsbyshelve_index(shelve_index);
                    dialog.openwindow open = lib.pubmethod.getopenwindow(this);
                    if (open != null)
                    {
                        application.current.properties["sweeplist"] = list;
                        open.closeastrue();
                    }
                }
            }
        }

        private void btncapture_click(object sender, routedeventargs e)
        {
            cameratimer.start();
        }

        private void restart_click(object sender, routedeventargs e)
        {
            cameratimer.stop();
            vce.play();
        }

        private void cb_selectionchanged(object sender, selectionchangedeventargs e)
        {
            //控件制定摄像头
            vce.videocapturesource = (string)cb.selecteditem;
        }

前台布局很简单，

 <grid>
        <grid.columndefinitions>
            <columndefinition width="86*"/>
            <columndefinition width="237*"/>
        </grid.columndefinitions>
        <grid.rowdefinitions>
            <rowdefinition height="5*"/>
            <rowdefinition height="*"/>
            <rowdefinition height="*"/>
        </grid.rowdefinitions>
        <stackpanel background="lightblue" grid.row="0" grid.columnspan="2">
            <wpfmedia:videocaptureelement x:name="vce" stretch="fill" width="auto" height="auto" margin="0" grid.row="0" rendertransformorigin="0.5,0.5">
                <wpfmedia:videocaptureelement.rendertransform>
                    <transformgroup>
                        <scaletransform/>
                        <skewtransform/>
                        <translatetransform/>
                    </transformgroup>
                </wpfmedia:videocaptureelement.rendertransform>
            </wpfmedia:videocaptureelement>
        </stackpanel>

        <label x:name="label" content="摄像头：" grid.row="1" grid.column="0"  width="49" horizontalalignment="right" margin="0,14,0,4" />
        <combobox x:name="cb" style="{staticresource query_combo}" grid.row="1" width="204" horizontalalignment="left" margin="2,13,0,8" selectionchanged="cb_selectionchanged" grid.column="1"  />
        <button  content="开始" x:name="btncapture" style="{staticresource query_button}" click="btncapture_click"  width="50" grid.row="2" grid.column="1" height="20" horizontalalignment="left" margin="9,10,0,14"/>
        <button  content="暂停" x:name="btnrestart" style="{staticresource query_button}" click="restart_click" width="50" grid.row="2" grid.column="1" height="20" horizontalalignment="left" margin="67,11,0,15"/>

    </grid>

需要注意的是xaml一定要引入  xmlns:wpfmedia="clr-namespace:wpfmediakit.directshow.controls;assembly=wpfmediakit" 。

效果如下。