Replace dynamically BitmapImage in Button (xaml)

Question

I have following code snippet in xaml:

<UserControl x:Class="Ournamespace.OurClassName"
             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"
    ...
             d:DesignHeight="250" d:DesignWidth="774" Loaded="UserControl_Loaded">

....
<Button Grid.Column="0" x:Name="Button_NewMarker" Style="{StaticResource ViewpointFlatButtonStyle}" Width="90" Height="65" 
    VerticalAlignment="Top" Click="Button_NewMarker_Click" x:FieldModifier="public" Margin="0,0,0,0" Grid.Row="1">
    <BitmapImage UriSource="Icons/markers_add_disabled.png" />
</Button>

and I have tried to replace image on button dynamically, by loading new image

if( !imgCache.ContainsKey(path) )
{
    BitmapImage bi = new BitmapImage();
    bi.BeginInit();
    bi.UriSource = new Uri(path, UriKind.Relative);
    bi.DownloadFailed += bi_DownloadFailed;
    bi.DecodeFailed += bi_DecodeFailed;
    bi.EndInit();
    imgCache[path] = bi;

}
Button_NewMarker.BeginInit();
Button_NewMarker.Content = imgCache[path];
//Button_NewMarker.Content = oldbmp;
Button_NewMarker.EndInit();

There is no error occurring (overridden events for this) and BitmapImage seems to be replaced - but for some reason it's grey. Images are added to project as resources, and first image loaded seems to be working - but not dynamically replaced one.

I have tried also to use <Image ... > and even <Image ... <ImageBitmap - but all of them are not working - I suspect it has something to do with our control being UserControl.

What I have seen in internet - there is huge amount of recommendations of what and how should be done - I want now this to be done with absolute minimum amount of code - and preferably without using binding and templating. Binding can be proposed as second step after everything is done manually.

Answer 1

If image files are managed as resource files (ie project files which have their Build Action set to Resource ) you should load them by a Resource File Pack URI .

Assuming a project folder Images with an image file Test.png :

var bi = new BitmapImage(new Uri("pack://application:,,,/Images/Test.png"));

---

Using the file name as key, the abobe would probably look like:

var path = "Test.png";
var uri = "pack://application:,,,/Images/" + path;

imgCache[path] = new BitmapImage(new Uri(uri));