<Window x:Class="摄像头调用.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="600" Width="800"
     xmlns:wpfmedia="clr-namespace:WPFMediaKit.DirectShow.Controls;assembly=WPFMediaKit"
        WindowStartupLocation="CenterScreen" >
    <Grid>
        <StackPanel Orientation="Vertical">
            <StackPanel Orientation="Horizontal">
                <ComboBox Name="cb" SelectionChanged="cb_SelectionChanged" Width="100" ></ComboBox>
                <Button  Width="80"  Content="拍" Name="btnCapture" Click="btnCapture_Click" Margin="200,0,0,0"></Button>
                <Button  Width="80"  Content="重拍" Name="btnReStart" Click="Restart_Click"></Button>
            </StackPanel>
            <wpfmedia:VideoCaptureElement Height="434" x:Name="vce" Stretch="Fill"  Margin="172,30,185,0" RenderTransformOrigin="0.5,0.5"  >
                <wpfmedia:VideoCaptureElement.RenderTransform>
                    <TransformGroup>
                        <ScaleTransform/>
                        <SkewTransform/>
                        <RotateTransform Angle="-90"/>
                        <TranslateTransform/>
                    </TransformGroup>
                </wpfmedia:VideoCaptureElement.RenderTransform>
            </wpfmedia:VideoCaptureElement>
        </StackPanel>
    </Grid>
</Window>

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.IO;
using WPFMediaKit.DirectShow.Controls;

namespace 摄像头调用
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            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");
            }
        }

        private void btnCapture_Click(object sender, RoutedEventArgs e)//拍照
        {
            RenderTargetBitmap bmp = new RenderTargetBitmap((int)vce.ActualWidth, (int)vce.ActualHeight,
                //vce是前台wpfmedia控件的name
                96, 96, PixelFormats.Default);
            //为避免抓不全的情况，需要在Render之前调用Measure、Arrange
            //为避免VideoCaptureElement显示不全，需要把
            //VideoCaptureElement的Stretch="Fill"
            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);
                byte[] captureData = ms.ToArray();
                File.WriteAllBytes(@"./photo/" + Guid.NewGuid().ToString().Substring(0, 5) + ".jpg", captureData);
            }
            vce.Pause();
        }

        //重拍
        private void Restart_Click(object sender, RoutedEventArgs e)
        {
            vce.Play();
        }

        private void cb_SelectionChanged(object sender, SelectionChangedEventArgs e)//ComboBox控件的选择事件
        {
            vce.VideoCaptureSource = (string)cb.SelectedItem;//vce是前台wpfmedia控件的name
        }
    }
}