WPF解决WindowsFormsHost背景透明

项目案例：WPF使用WindowsFormsHost播放视频，视频上显示边框、字幕等特效；

难点问题

1、WindowsFormsHost不支持背景透明；

2、WPF Panel.ZIndex无效，WindowsFormsHost更优先；

3、使用Show打开两个窗口，数据同步延时

解决方案：

使用Popup，解决最顶层、解决背景透明

使用Canvas，解决元素拖拽

XAML

<ctrl:uiPopup x:Name="canvas" VerticalOffset="-410" IsOpen="True" AllowsTransparency="True" PopupAnimation="Fade">
    <Canvas  Height="410" Width="548">
        <Image x:Name="PanelLeft" Height="410" Width="45" Canvas.Left="0"></Image>
        <Image x:Name="PanelTop" Height="45" Width="548" Canvas.Top="0"></Image>
        <Image x:Name="PanelRight" Height="410" Width="45" Canvas.Right="0"></Image>
        <Image x:Name="PanelBottom" Height="45" Width="548" Canvas.Bottom="0"></Image>
        <Image x:Name="PanelPlus" Height="100" Width="100" Panel.ZIndex="1"></Image>
    </Canvas>
</ctrl:uiPopup>

ctrl:uiPopup控件，参考： 自定义WPF Popup控件　　

C#

//注册移动事件
PanelPlus.MouseLeftButtonDown += rectOne_MouseLeftButtonDown;
PanelPlus.MouseLeftButtonUp += rectOne_MouseLeftButtonUp;
PanelPlus.MouseMove += rectOne_MouseMove;

bool enableMove = false;
double spanLeft = 0;
double spanTop = 0;
//鼠标移动
private void rectOne_MouseMove(object sender, MouseEventArgs e)
{
    if (enableMove)
    {
        var cLeft = e.GetPosition(canvas).X - spanLeft;
        var cTop = e.GetPosition(canvas).Y - spanTop;
        //设置矩形的位置
        Canvas.SetLeft(PanelPlus, cLeft);
        Canvas.SetTop(PanelPlus, cTop);
    }
}
//鼠标松开
private void rectOne_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    //释放鼠标捕获
    PanelPlus.ReleaseMouseCapture();
    enableMove = false;
}
//鼠标按下
private void rectOne_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    var y = Convert.ToDouble(e.GetPosition(canvas).Y);
    y = Utils.IsNumber(y) ? y : 0;
    var x = Convert.ToDouble(e.GetPosition(canvas).X);
    x = Utils.IsNumber(x) ? x : 0;

    //创建鼠标捕获
    Mouse.Capture(PanelPlus);
    double l = Convert.ToDouble(Canvas.GetLeft(PanelPlus));
    l = Utils.IsNumber(l) ? l : 0;
    double t = Convert.ToDouble(Canvas.GetTop(PanelPlus));
    t = Utils.IsNumber(t) ? t : 0;
    spanLeft = x - l;
    spanTop = y - t;
    enableMove = true;
}

public class Utils
{
    //判断字符串是否为纯数字  
    public static bool IsNumber(object str)
    {
        if (str == null) return false;
        ASCIIEncoding ascii = new ASCIIEncoding();
        byte[] bytestr = ascii.GetBytes(str.ToString());

        foreach (byte c in bytestr)
        {
            if (c < 48 || c > 57) 
            {
                return false;
            }
        }
        return true;
    }
}