[英]Bind Image Source in WPF to a Url
我一直在瀏覽不同的帖子,試圖弄清楚我的問題有什么問題。 基本上我的用戶控件上有一個Image標簽,而我想要綁定到一個url。 但是這不起作用。 我嘗試使用返回BitmapImage(new Uri((string)value));
的ValueConverter BitmapImage(new Uri((string)value));
但這不起作用。 我唯一能得到的是你不能綁定到一個url,你必須下載你想要綁定的圖像。 我不想下載我seacrch的所有圖像。 是否需要在本地下載圖像來完成此任務。 我認為通過返回BitmapImage,ValueConverter方法將是最好的。 請幫忙?
public class MyViewModel
{
private string _posterUrl;
public string PosterUrl
{
get
{
//Get Image Url, this is an example and will be retrieved from somewhere else.
_posterUrl = "http://www.eurobuzz.org/wp-content/uploads/2012/08/logo.jpg";
return _posterUrl;
}
set
{
_posterUrl = value;
NofityPropertyChanged(p => p.PosterUrl);
}
}
}
這是我的ValueConverter:
public class BitmapImageConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if(value is string)
return new BitmapImage(new Uri((string)value, UriKind.RelativeOrAbsolute));
if(value is Uri)
return new BitmapImage((Uri)value);
throw new NotSupportedException();
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotSupportedException();
}
}
這是我的XAML:
<Image Source="{Binding PosterUrl, Converter={StaticResource bitmapImageConverter}}" Width="100" Height="100" />
因此,它綁定到包含imageurl的PosterUrl屬性,並將其轉換為bitmapimage。 有任何想法嗎?
試試吧
<Image Helpers:ImageAsyncHelper.SourceUri="{Binding Url, IsAsync=True}" x:Name="img" />
哪里
using System;
using System.Windows;
using System.Windows.Data;
using System.Windows.Controls;
public class ImageAsyncHelper : DependencyObject {
public static Uri GetSourceUri(DependencyObject obj){
return (Uri)obj.GetValue(SourceUriProperty);
}
public static void SetSourceUri(DependencyObject obj, Uri value){
obj.SetValue(SourceUriProperty, value);
}
public static readonly DependencyProperty SourceUriProperty =
DependencyProperty.RegisterAttached("SourceUri",
typeof(Uri),
typeof(ImageAsyncHelper),
new PropertyMetadata { PropertyChangedCallback = (obj, e) =>
((Image)obj).SetBinding(
Image.SourceProperty,
new Binding("VerifiedUri"){
Source = new ImageAsyncHelper{
_givenUri = (Uri)e.NewValue
},
IsAsync = true
}
)
}
);
private Uri _givenUri;
public Uri VerifiedUri {
get {
try {
System.Net.Dns.GetHostEntry(_givenUri.DnsSafeHost);
return _givenUri;
}
catch (Exception) {
return null;
}
}
}
}
和
public Uri Url {
get {
return new Uri(SomeString, UriKind.Absolute);
}
}
你想這樣做嗎?
<UserControl x:Class="WpfApplication1.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<StackPanel Orientation="Vertical">
<Image Height="100" Width="100" Source="{Binding}" />
<Image Height="100" Width="100" Source="http://www.eurobuzz.org/wp-content/uploads/2012/08/logo.jpg"/>
</StackPanel>
代碼背后:
public partial class UserControl1 : UserControl
{
public UserControl1()
{
this.DataContext = "http://www.eurobuzz.org/wp-content/uploads/2012/08/logo.jpg";
InitializeComponent();
}
}
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