WPF image show web picture via url and converter
<Window.Resources> <local:ImageUrlConverter x:Key="imgConverter"/> </Window.Resources> <Image Source="{Binding ImgUrl,Converter={StaticResource imgConverter}}" RenderOptions.BitmapScalingMode="HighQuality"/> public class ImageUrlConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { string url = value?.ToString(); if (!string.IsNullOrWhiteSpace(url)) { WebClient client = new WebClient(); var imgBytes = client.DownloadData(url); if (imgBytes != null && imgBytes.Any()) { MemoryStream ms = new MemoryStream(imgBytes); ms.Seek(0, SeekOrigin.Begin); BitmapImage bmi = new BitmapImage(); bmi.BeginInit(); bmi.StreamSource = ms; bmi.EndInit(); if (bmi.CanFreeze) { bmi.Freeze(); } return bmi; } } return null; } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { throw new NotImplementedException(); } }
//xaml <Window x:Class="WpfApp1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:behavior="http://schemas.microsoft.com/xaml/behaviors" xmlns:local="clr-namespace:WpfApp1" mc:Ignorable="d" WindowState="Maximized" WindowStyle="None" Title="MainWindow" Height="450" Width="800"> <Window.DataContext> <local:MainVM/> </Window.DataContext> <Window.Resources> <local:ImageUrlConverter x:Key="imgConverter"/> </Window.Resources> <behavior:Interaction.Triggers> <behavior:EventTrigger EventName="MouseDown"> <behavior:InvokeCommandAction Command="{Binding MouseDownCommand}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Window}}}"/> </behavior:EventTrigger> </behavior:Interaction.Triggers> <Grid> <Image Source="{Binding ImgUrl,Converter={StaticResource imgConverter}}" RenderOptions.BitmapScalingMode="HighQuality"/> </Grid> </Window> //cs using System; using System.Collections.Generic; using System.ComponentModel; using System.Globalization; using System.IO; using System.Linq; using System.Net; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; namespace WpfApp1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } } public class MainVM : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public string ImgUrl { get; set; } = "https://wx4.sinaimg.cn/mw690/007ucPXmgy1hteb8tr7gjj311x1kwhdt.jpg"; public DelCmd MouseDownCommand { get; set; } public MainVM() { InitCommands(); } private void InitCommands() { MouseDownCommand = new DelCmd(MouseDownCommandExecuted); } private void MouseDownCommandExecuted(object obj) { var win = obj as Window; if (win != null) { var pt = Mouse.GetPosition(win); MessageBox.Show($"X:{pt.X}\nY:{pt.Y}", "Location", MessageBoxButton.OK); } } private void OnPropertyChanged(string propertyName) { var handler = PropertyChanged; if (handler != null) { handler?.Invoke(this, new PropertyChangedEventArgs(propertyName)); } } } public class ImageUrlConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { string url = value?.ToString(); if (!string.IsNullOrWhiteSpace(url)) { WebClient client = new WebClient(); var imgBytes = client.DownloadData(url); if (imgBytes != null && imgBytes.Any()) { MemoryStream ms = new MemoryStream(imgBytes); ms.Seek(0, SeekOrigin.Begin); BitmapImage bmi = new BitmapImage(); bmi.BeginInit(); bmi.StreamSource = ms; bmi.EndInit(); if (bmi.CanFreeze) { bmi.Freeze(); } return bmi; } } return null; } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { throw new NotImplementedException(); } } public class DelCmd : ICommand { public event EventHandler CanExecuteChanged { add { CommandManager.RequerySuggested += value; } remove { CommandManager.RequerySuggested -= value; } } private Action<object> execute; private Predicate<object> canExecute; public DelCmd(Action<object> executeValue, Predicate<object> canExecuteValue) { this.execute = executeValue; this.canExecute = canExecuteValue; } public DelCmd(Action<object> executeValue) : this(executeValue, null) { } public bool CanExecute(object parameter) { if (canExecute == null) { return true; } return canExecute(parameter); } public void Execute(object parameter) { execute(parameter); } } }