wpf imagesource=null 同时清空内存

确保imagesource只有image控件引用的情况下，这么赋值：

BitmapImage image = new BitmapImage();
image.BeginInit();
image.CacheOption = BitmapCacheOption.OnLoad;
image.UriSource = new Uri(list[current], UriKind.RelativeOrAbsolute);
image.EndInit();

        Image imageControl = new Image();
        imageControl.Source = image;

测试代码：
///

/// MainWindow.xaml 的交互逻辑
///

public partial class MainWindow : Window
{
List list = new List();
public MainWindow()
{
InitializeComponent();
string dir = @"C:\Users\Sam\Pictures\大图";
for (int i = 0; i < 6; i++)
{
list.Add($"{dir}{i}.png");
}
}

    int current = 0;
    int max = 5;

    //HttpClient httpClient = new HttpClient();
    private /*async*/ void Button_Click(object sender, RoutedEventArgs e)
    {

        //不清空图片控件，清除每个图片控件的source
        foreach (var item in container.Children)
        {
            if (item is Image)
            {
                Image img = (Image)item;
                img.Source = null;
            }
        }

        ////清空图片控件--ok，可以清空内存
        //var listx = new List<Image>();
        //for (int i = 0; i < container.Children.Count; i++)
        //{
        //    if (container.Children[i] is Image)
        //    {
        //        Image img = (Image)container.Children[i];
        //        listx.Add(img);
        //    }
        //}
        //foreach (var item in listx)
        //{
        //    container.Children.Remove(item);
        //}

        GC.Collect();

        //Image image = new Image();
        //image.Source = new BitmapImage(new Uri(list[current], UriKind.RelativeOrAbsolute));

        BitmapImage image = new BitmapImage();
        image.BeginInit();
        image.CacheOption = BitmapCacheOption.OnLoad;
        image.UriSource = new Uri(list[current], UriKind.RelativeOrAbsolute);
        image.EndInit();

        Image imageControl = new Image();
        imageControl.Source = image;

        container.Children.Add(imageControl);

        current++;
        if (current > max)
        {
            current = 0;
        }
      
       
    }

    





}