SteveCooper.org

I’m learning WPF, very slowly, as a background thing.

I’m working very slowly through some WPF at the moment, and discovered something I thought was really odd. The classic .Net Image class — System.Drawing.Image — can’t be easily databound into the WPF Image control.

That seemed crazy to me — it’s like having a PictureBox control without an Image property. I resolved to fix it in the most ‘WPFy’ way I could.

What I’d tried was binding a ListView to a list of objects, like so;

<ListView 
    ItemsSource="{ Binding Path=. }"
    ItemTemplate="{DynamicResource EventTemplate}">   

Id bound to an object which declares two properties;

string DisplayName { get; }
System.Drawing.Image Image { get; set; }

I wanted to populate a DataTemplate but if I did this in my template;

<StackPanel Orientation="Horizontal">
    <Image Source="{ Binding Path=Image }" />
    <TextBlock Text="{ Binding Path=DisplayName }" />
</StackPanel>      

The text appears but the image does not. It turns out that WPF can’t find a suitable converter.

So, thanks to Reed Copsey and his very helpful pointer on Stack Overflow, and this tutorial, I’ve found a way I’m happy with; one that doesn’t involve c# code-behind.

I’ve created an IValueConverter which does the conversion from System.Drawing.Image to System.Windows.Media.ImageSource. A big thank-you to Matt Galbraith of Microsoft for providing the core code;

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. Add the namespace declaration to the window;

xmlns:med="clr-namespace:System.Windows.Media"

Stick an instance of the ImageConverter into a static resource;

<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} }" />

So. A re-usable converter which allows databinding directly to GDI image objects.

Originally discussed on stack overflow

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I get into work anywhere between 8:00am and 9:30am. As the end of the day draws on, I’m sometimes not sure whether I’ve served my time. To make sure I don’t go home too early, I use this little trick.

Windows tracks your logons in the event log. So to find out when you came in;

1. Open the event viewer; *windows+r, ‘eventvwr’, enter*
2. Select ‘Custom Views’
3. Right-click and choose ‘Create custom view…’
4. Open the ‘XML’ tab
5. Check ‘Edit query manually’
6. Enter this XML; <QueryList> <Query Id="0" Path="Security"> <Select Path="Security">*[System[(EventID=4672)] and EventData[Data[@Name='SubjectUserName'] = 'your-name-here']]</Select> </Query> </QueryList>
7. Replace ‘your-name-here’ with your domain username
8. Choose ‘OK’.
9. Set the name to ‘Logins’
10. Hit ‘OK’.

And there you go. There in Custom Views will be a list of your login events. Find the earliest one in the day and that’s when you first logged in.

Huge firework display, candy floss, and an eighties medley. Perfect.

Here they are before the reveal. Let’s see how close I got…

Also added Clare’s image;