我正在尝试显示Windows应用中默认图片库中的所有图像,但我只能显示图像的名称,而不是文件夹中的所有图像,这是我的代码。
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using Windows.UI.Xaml.Media.Imaging;
using Windows.Storage.Streams;
using Windows.Storage;
// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238
namespace ListView
{
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class MainPage : Page
{
public MainPage()
{
this.InitializeComponent();
showall();
}
public async void showall()
{
IReadOnlyList<StorageFile> file = await KnownFolders.PicturesLibrary.GetFilesAsync();
foreach (StorageFile file1 in file)
{
list.Items.Add(file1.Name);
}
}
这是XAML代码...
<Page
x:Class="ListView.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:ListView"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<StackPanel>
<StackPanel HorizontalAlignment="Left" Width="350" Height="350">
<ListView Width="300" Height="300" Name="list" SelectionChanged="list_SelectionChanged">
<Image Width="200" Height="200" Name="img"></Image>
</ListView>
</StackPanel>
<StackPanel VerticalAlignment="Top">
<Image Width="300" Height="300" Name="img1" />
<TextBlock Width="300" Height="30" Name="txt1" />
</StackPanel>
</StackPanel>
</Grid>
没有自动转换从存储文件到图像。
您需要两件事,首先是listView中带有图像控件的DataTemplate:
<ListView x:Name="list">
<ListView.ItemTemplate>
<DataTemplate>
<Image Source="{Binding}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
第二,从存储文件创建的位示意图,这些bitmapimages被添加到项目集合而不是文件名:
:public MainPage()
{
InitializeComponent();
Loaded += OnLoaded;
}
private async void OnLoaded(object sender, RoutedEventArgs e)
{
list.Items.Clear();
var files = await KnownFolders.PicturesLibrary.GetFilesAsync();
foreach (var file in files)
{
var bitmap = new BitmapImage();
using (var stream = await file.OpenReadAsync())
{
await bitmap.SetSourceAsync(stream);
}
list.Items.Add(bitmap);
}
}
还请注意,加载是在Loaded
事件处理程序中完成的,而不是直接调用异步方法而无需等待它。事件处理程序是唯一可以安全地成为async void
且不等待的方法。
虽然克莱门斯(Clemens)的方法对您有效,但我想向您展示另一种方法。使用ViewModels。
这是一个PicturesViewModel:
public class PicturesViewModel
{
public ObservableCollection<ImageSource> MyImages { get; }
= new ObservableCollection<ImageSource>();
public async Task GetImages()
{
var files = await KnownFolders.PicturesLibrary.GetFilesAsync();
foreach (var file in files)
{
using (var stream = await file.OpenReadAsync())
{
BitmapImage image = new BitmapImage();
await image.SetSourceAsync(stream);
MyImages.Add(image);
}
}
}
}
通常,如果它是同步活动,则可以在构造函数中写下逻辑。由于这是异步的,因此我在视图模型中使用另一种方法来加载BitmapImage
S
List
现在在您的MainPage_Loaded
中(Mainpage的Loaded
事件的处理程序方法如其他答案所示)您需要这样做:
private async void MainPage_Loaded(object sender, RoutedEventArgs e)
{
var viewModel = new PicturesViewModel();
DataContext = viewModel;
await viewModel.GetImages();
}
,您的listView只是Binding
<ListView ItemsSource="{Binding MyImages}">
<ListView.ItemTemplate>
<DataTemplate>
<Image Source="{Binding}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>