using XAML to bind to a System.Drawing.Image into a System.Windows.Image control
I'm binding a ListView to a list of objects, like so;
<ListView
ItemsSource="{ Binding Path=. }"
ItemTemplate="{DynamicResource EventTemplate}">
I'm binding to an object which declares two properties;
string DisplayName { get; }
System.Drawing.Image Image { get; set; }
I want to populate a DataTemplate
but I can't figure out how; if I do this in my template;
<StackPanel Orientation="Horiz开发者_JAVA百科ontal">
<Image Source="{ Binding Path=Image }" />
<TextBlock Text="{ Binding Path=DisplayName }" />
</StackPanel>
The text appears but the image does not. What am I doing wrong? The debug output shows
System.Windows.Data Error: 1 : Cannot create default converter
to perform 'one-way' conversions between types
'System.Drawing.Image' and 'System.Windows.Media.ImageSource'.
Consider using Converter property of Binding.
BindingExpression:Path=Image; DataItem='RealElement'
(HashCode=54308798); target element is 'Image' (Name='');
target property is 'Source' (type 'ImageSource')
Found a way I'm happy with. Using Reed Copsey's pointer and this tutorial I've wrapped the code as a IValueConverter
.
Here's the converter from System.Drawing.Image
to System.Windows.Media.ImageSource
;
using System;
using System.Drawing.Imaging;
using System.Globalization;
using System.IO;
using System.Windows.Data;
namespace System.Windows.Media
{
/// <summary>
/// One-way converter from System.Drawing.Image to System.Windows.Media.ImageSource
/// </summary>
[ValueConversion(typeof(System.Drawing.Image), typeof(System.Windows.Media.ImageSource))]
public class ImageConverter : IValueConverter
{
public object Convert(object value, Type targetType,
object parameter, CultureInfo culture)
{
// empty images are empty...
if (value == null) { return null; }
var image = (System.Drawing.Image)value;
// Winforms Image we want to get the WPF Image from...
var bitmap = new System.Windows.Media.Imaging.BitmapImage();
bitmap.BeginInit();
MemoryStream memoryStream = new MemoryStream();
// Save to a memory stream...
image.Save(memoryStream, ImageFormat.Bmp);
// Rewind the stream...
memoryStream.Seek(0, System.IO.SeekOrigin.Begin);
bitmap.StreamSource = memoryStream;
bitmap.EndInit();
return bitmap;
}
public object ConvertBack(object value, Type targetType,
object parameter, CultureInfo culture)
{
return null;
}
}
}
Then you need to bring the image converter into XAML as a resource;
xmlns:med="clr-namespace:System.Windows.Media"
...
<ListView.Resources>
<med:ImageConverter x:Key="imageConverter" />
</ListView.Resources>
Then you can use it in XAML to bind directly to the Image, using the new converter;
<Image Source="{ Binding Path=Image, Converter={StaticResource imageConverter} }" />
You can't bind that directly - you need to have some type of converter that will convert from a GDI Image to a WPF Image.
Here is one approach - it uses a memory stream to pull the data from the GDI image and create a BitmapSource object.
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