为啥 XamlIslands Image 控件不显示图像？

Posted 2023-04-01

【中文标题】为啥 XamlIslands Image 控件不显示图像？

【英文标题】：Why does the XamlIslands Image control not display the image?为什么 XamlIslands Image 控件不显示图像？

【发布时间】：2020-07-24 01:41:12

【问题描述】：

我试图让用户选择一个文件，然后在 XamlIslands GridView 上显示该文件的图标。用户选择一个文件后（文件的文件路径为myfile），该文件的图标随后保存到C:\LauncherX\Temp\Icons。该图标保存得很好，因为我可以打开它并查看它，但是，当我尝试在 XamlIsland Image 控件中显示它时，它只显示某些图像。 例如，这是我要显示的两个图标：

这个图标叫做Github Desktop.png

和

这个图标叫做TextIcon.png

Xaml IslandsImage 控件显示 Github Desktop.png 非常好：

但是，无论出于何种原因，它都不会显示 TextIcon.png

这是 C# 代码：

private void Button_Click(object sender, Windows.UI.Xaml.RoutedEventArgs e)
        

            //init a gridview
            var gridView = gridviewhost.Child as Windows.UI.Xaml.Controls.GridView;

            //init open file dialog
            OpenFileDialog openFileDialog = new OpenFileDialog()  DereferenceLinks = false ;



            //check if openfile dialog is ok
            if (openFileDialog.ShowDialog() == true)
            

                //and then get the icon and put it in into the grid view
                foreach (string myfile in openFileDialog.FileNames)
                
                    //init filename
                    var filename = System.IO.Path.GetFileName(myfile);
                    filename = filename.Remove(filename.Length - 4);
                    filename = filename + ".png";

                    //save file icon
                    if(File.Exists(Path.Combine("C:\\LauncherX\\Temp\\Icons", filename)))
                    
                        filename = count.ToString() + filename;

                        FileStream stream = new FileStream(System.IO.Path.Combine("C:\\LauncherX\\Temp\\Icons\\", filename), FileMode.Create);
                        Bitmap icon1 = new Bitmap(System.Drawing.Icon.ExtractAssociatedIcon(myfile).ToBitmap());
                        icon1.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                        count += 1;

                    
                    else
                    
                        FileStream stream = new FileStream(System.IO.Path.Combine("C:\\LauncherX\\Temp\\Icons\\", filename), FileMode.Create);
                        Bitmap icon1 = new Bitmap(System.Drawing.Icon.ExtractAssociatedIcon(myfile).ToBitmap());
                        icon1.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                    

                    //create a stackpanel
                    Windows.UI.Xaml.Controls.StackPanel stackpanel = new Windows.UI.Xaml.Controls.StackPanel();
                    stackpanel.Width = 85;
                    stackpanel.Height = 85;

                    //load file icon into uwp image control
                    Windows.UI.Xaml.Controls.Image image = new Windows.UI.Xaml.Controls.Image();
                    image.Width = 50;
                    image.Height = 50;
                    string path = Path.Combine(@"C:\LauncherX\Temp\Icons\" + filename);
                    Uri fileuri = new Uri(path);                    
                    image.Source = new Windows.UI.Xaml.Media.Imaging.BitmapImage(fileuri);
                    image.VerticalAlignment = Windows.UI.Xaml.VerticalAlignment.Top;
                    image.HorizontalAlignment = Windows.UI.Xaml.HorizontalAlignment.Center;

                    //create a textblock
                    //TODO: fix the text
                    Windows.UI.Xaml.Controls.TextBlock textblock = new Windows.UI.Xaml.Controls.TextBlock();
                    textblock.FontSize = 11;
                    textblock.TextWrapping = Windows.UI.Xaml.TextWrapping.Wrap;
                    textblock.Text = filename.Remove(filename.Length - 4);
                    textblock.HorizontalAlignment = Windows.UI.Xaml.HorizontalAlignment.Stretch;
                    textblock.VerticalAlignment = Windows.UI.Xaml.VerticalAlignment.Bottom;
                    textblock.TextAlignment = Windows.UI.Xaml.TextAlignment.Center;

                    //add the controls
                    stackpanel.Children.Add(image);
                    stackpanel.Children.Add(textblock);
                    gridView.Items.Add(stackpanel);

                    //TODO: Save the item using text documents

                
            
        

这里是 Xaml 代码：

    <Grid>
        <xamlHost:WindowsXamlHost x:Name="OpenFileHost" InitialTypeName="Windows.UI.Xaml.Controls.Button" Margin="0,10,10,0" HorizontalAlignment="Right" VerticalAlignment="Top" Height="32" RenderTransformOrigin="0.5,0.5" Width="105" ChildChanged="OpenFileHost_ChildChanged"/>
        <TextBlock x:Name="textBlock" HorizontalAlignment="Left" Margin="10,10,0,0" TextWrapping="Wrap" Text="My applications" VerticalAlignment="Top" FontWeight="Bold" FontSize="16"/>
        <xamlHost:WindowsXamlHost Margin="10,47,10,10.5" x:Name="gridviewhost" InitialTypeName="Windows.UI.Xaml.Controls.GridView"/>
    </Grid>

你能帮帮我吗？

谢谢

【问题讨论】：

确保所有图标的扩展名是.png 并尝试注释掉这一行filename = filename + ".png"; 然后检查。

@RaoHammasHussain 如果我从文件（如文本文件或快捷方式文件）中提取图标，如何确保所有图标的扩展名都是 .png？我该怎么做？

文件名应以 .png string.endswith() 结尾。或 path.getextension()。

@Andy 当用户选择一个文件（例如 Text.txt）时，文件名给了我“Text.txt”的值所以，我需要在末尾添加 .png 以便当我保存此文件的图标（通过 System.Drawing.Icon.ExtractAssosiatedIcon(myfile) 完成）时，它会将其保存为 .png 文件。查看代码了解更多详情。

但是你为什么要保存一个带有.png扩展名的.txt文件呢？这就是为什么在使用 path.getextension() 或只是 Yourstring.endsWith() 或我猜是 Yourstring.Contains() 之前检查扩展名

【参考方案1】：

好的，结果将扩展名设置为.tiff 似乎有效。