wpf dynamic image loading exception - wpf

I am trying to load an image from my hard drive (not a project folder) dynamically. When I hard code the path, the image loads just fine:
<Border>
<Border.Background>
<ImageBrush ImageSource="C:\Program Files\my program\Working Assets\Logos\background.jpg" />
</Border.Background>
However, when I try to load the image dynamically, the path cannot be found.
c# file:
public static string BACKGROUND_IMAGE_PATH = "C:\\Program Files\\my program\\Working Assets\\Logos\\background.jpg";
xaml:
xmlns:localVariables="clr-namespace:my_namespace.StaticResources">
<Border BorderBrush="{Binding ColorsBo.BorderColor, FallbackValue='Black'}">
<Border.Background>
<ImageBrush ImageSource="{x:Static localVariables:VC.BACKGROUND_IMAGE_PATH}" />
</Border.Background>
When I look at the logs and copy the path that the compiler says it cant find, it takes me directly to the resource. Does anyone know why can't the resource be found when I try to load it dynamically?

Try this:
<ImageBrush ImageSource="{Binding Source={x:Static localVariables:VC.BACKGROUND_IMAGE_PATH}}" />
For an explanation, see the Remarks section in x:Static Markup Extension:
Use caution when you make x:Static references that are not directly the type of a property's value. In the XAML processing sequence, provided values from a markup extension do not invoke additional value conversion. This is true even if your x:Static reference creates a text string, and a value conversion for attribute values based on text string typically occurs either for that specific member or for any member values of the return type.
In contrast to the above, built-in automatic type conversion (e.g. from string to ImageSource) is applied to the value produced by a Binding.

The ImageBrush.ImageSource does not require a string
to make this work you need to create a new ImageSource
public static ImageSource BACKGROUND_IMAGE_PATH = new BitmapImage(new Uri("C:\\Program Files\\my program\\Working Assets\\Logos\\background.jpg"));

Related

Using Bitmap Class in XAML [duplicate]

I have two .png files added to my resources which I need to access their Uri when doing binding.
My xaml code is as followed:
<Grid>
<Image>
<Image.Source>
<BitmapImage DecodePixelWidth="10" UriSource="{Binding Path=ImagePath}"/>
</Image.Source>
</Image>
</Grid>
and the binding code using ImagePath is:
ImagePath = resultInBinary.StartsWith("1") ? Properties.Resources.LedGreen : Properties.Resources.ledRed;
However
Properties.Resources.LedGreen
returns a Bitmap instead of String containing the Uri of that particular image.
I just want to know how to extract that value without a need to address a path of the image in the directory that it's stored. (Which honestly I am not sure is a right thing to do as I couldn't find any similar situation on the net).
Please let me know if there is even a preferred method to the one I am trying to use if available.
In a WPF application you would usually not store images in Properties/Resources.resx and access them by means of the Properties.Resources class.
Instead you just add the image files to your Visual Studio project as regular files, perhaps in a folder named "Images" or the like. Then you would set their Build Action to Resource, which is done in the Properties window. You get there e.g. by right-clicking the image file and select the Properties menu item. Note that the default value of the Build Action should be Resource for image files anyways.
In order to access these image resources from code you would then use a Pack URI. With the above folder name "Images" and an image file named "LedGreen.png", creating such an URI would look like this:
var uri = new Uri("pack://application:,,,/Images/LedGreen.png");
So you could perhaps declare your property to be of type Uri:
public Uri ImageUri { get; set; } // omitted INotifyPropertyChanged implementation
and set it like this:
ImageUri = resultInBinary.StartsWith("1")
? new Uri("pack://application:,,,/Images/LedGreen.png")
: new Uri("pack://application:,,,/Images/LedRed.png");
Finally your XAML should look like shown below, which relies on built-in type conversion from Uri to ImageSource:
<Grid>
<Image Width="10" Source="{Binding Path=ImageUri}" />
</Grid>
Declare the Properties.Resources.LedGreen property as ImageSource and set it to Uri location rather than the Bitmap object.
Or if you insist of storing it as a bitmap you can get the source by returning Properties.Resources.LedGreen.ImageSource which will be of type ImageSource.
I would prefer the first approach.

Images bound to images added to resx files using XAML

My WPF application includes a resource file MyResources.resx, containing several strings and images. Because the application will need to be localized, all my references to globalized resources must be made via named properties of the auto-generated MyResources class. The following code works well for string resources:
<Button Content="{x:Static local:Properties.MyResources.ButtonText}" />
However the same does not work for images. Assuming I have an image eflag.bmp added to the resources as a resource named Flag, I would like to be able to do something like this:
<Image Source="{x:Static local:Properties.MyResources.Flag}" />
Please note that the following alternative approach:
<Image Source="/MyNamespace;component/Resources/eflag.bmp" />
cannot be used in this case because it will not be able to handle localization. The problem can be solved using code behind but I am looking for a XAML based solution.
Turn your x:Static into a Binding.Source and add a Converter which does Bitmap to ImageSource.
Source="{Binding Source={x:Static local:Properties.MyResources.Flag},
Converter={StaticResource BitmapToImageSourceConverter}}"
Alternatively you can make the converter a custom markup extension which takes a Bitmap and returns the ImageSource in ProvideValue.
Source="{me:BitmapToImageSource {x:Static local:Properties.MyResources.Flag}}"

binding an image source in XAML

I am trying to bind an image source to my XAML through c#
this works
<Image Source="images/man.jpg"></Image>
this does not work
<Image Source="images/{Binding imagesource}"></Image>
where imagesource is a string variable in the c# file of this xaml and is being set equal to "man.jpg"
here is a way how to do it in XAML:
add this to the namespace:
xmlns:System="clr-namespace:System;assembly=mscorlib"
then add your images paths
<System:String x:Key="ImageRefresh">/Theme;component/Images/icon_refresh.png</System:String>
<System:String x:Key="ImageSearch">/Theme;component/Images/icon_search.png</System:String>
This is how you use it
<Image Height="16" Source="{StaticResource ImageSearch}" Stretch="Uniform" Width="16"/>
This works ok, but if you load your xaml style in Blend it will go bogus..
An object of type "System.String" cannot be applied to a property that expects the type "System.Windows.Media.ImageSource".
I haven't figured out yet, how to replace System:String with that Media.ImageSource... but hey.. it works for me in Visual Studio.
You can't stick a binding mid-way through the value like that. It's either a binding, or it's not. Assuming imagesource is publicly accessible via your DataContext, you could do this:
<Image Source="{Binding imagesource}"/>
However, if it's been set to "man.jpg" then it won't find the image. Either set imagesource to the full path ("images/man.jpg") or use a converter:
<Image Source="{Binding imagesource, Converter={StaticResource RelativePathConverter}}"/>
The converter would prepend "images/" onto its value. However, it may be necessary for the converter to return an ImageSource rather than a string.
Images have bitten me in the past. There is a certain lookup order involved.
When you use "image/man.jpg" it could refer to a file inside your silverlight xap, or relative to the location of XAP file. For example, it could be in YourProject.Web/ClientBin/image/man.jpg.
You should troubleshoot by using full URLs first and find out if this works.
imagesource needs to be an actual Image object, not a string.
Here is a method that will create a new Image object given a path:
public BitmapImage Load(string path)
{
var uri = new Uri(path);
return new BitmapImage(uri);
}

Adding Enumeration Value to Silverlight Attribute/Property

In the <ImageBrush/> element, there are AlignmentX and AlignmentY attributes with values Left/Center/Right and Top/Center/Bottom, respectively.
What I'm wanting to do is set my own value in, for example, AlignmentX either as a value or as another enumeration like AlignmentX="HalfCenter" where HalfLeft equals my own value (halfway between Center and Left). For example, if I have this:
<Rectangle Canvas.Left="0" Stroke="LimeGreen" StrokeThickness="16" Canvas.Top="0"
Width="400" Height="400" >
<Rectangle.Fill>
<ImageBrush ImageSource="newone.jpg"
Stretch="None" AlignmentX="HalfLeft" AlignmentY="Top" />
</Rectangle.Fill>
</Rectangle>
I don't know if this is a Dependency Property, Attached Property or otherwise (don't yet know how to create those). In the helpfile, it says in TileBrush.AlignmentXProperty field: Public Shared ReadOnly AlignmentXProperty As DependencyProperty. Does the ReadOnly word here mean that I can't set this property to a custom property?
If this can't be an override of that property, how can I create my own? I think this is an Attached Property and it could be called something different, like OffsetX and OffsetY that set an ImageBrush to a location inside its parent Shape. I'm getting very confused by the SL documentation on how I would do this though (almost no examples in VB.NET - but even the C# ones aren't all that revealing).
If it is possible, how would I get started on this?
Save yourself the pain and just use a value convertor and even that is going to be a little tricky, since you are going to have to apply a rendertransform or something to react to your enums.
You also could write your own panel which is probably a better idea.
You have a few different problems here to confront, creating the attached property, validating the enum, having the enum do what you want it to do when it is set.
Your also going to have to learn about MeasureOverride and ArrangeOverride
If you just can't help yourself ... Look Here

Pack URI and path not resolving image in WPF

I have the following directory structure
Project
\Images
+view.png
control.xaml
and in the control I have a button defined by the following XAML:
<Button Click="Search"
Grid.Column="1"
Margin="0,5,5, 0"
HorizontalAlignment="Right">
<Button.Template>
<ControlTemplate TargetType="{x:Type Button}">
<Image Source="pack://application:,,,/images/view.png"
Width="16"
Height="16"
ToolTip="Search"
Cursor="Hand"
Opacity="0.8" />
</ControlTemplate>
</Button.Template>
</Button>
However, neither this pack URI method nor the "/images/view.png" is working. As I understand it, this is the same issue this question raises. However, I get the same error. The confusing thing is that in designer in Visual Studio 2008, the image renders correctly, but on the call to the InitializeComponent() call, I get:
Cannot convert string 'pack://application:,,,/images/view.png' in attribute 'Source' to object of type 'System.Windows.Media.ImageSource'. Cannot locate resource 'images/view.png'. Error at object 'System.Windows.Controls.ControlTemplate' in markup file 'RecapSpecEditControl;component/modaltreadgroupdatadialog.xaml' Line 61 Position 40.
I thought that maybe there was a namespace that I had to declare but according to the msdn site I believe I don't have to do anything like that.
I actually got this to work, but had to set my source to "/ProjectName;component/images/view.png" Because I have the ProjectName as a referenced assembly this is then the same as the Path: portion at the msdn page that I referenced in the question.
Set the Build Action for 'view.png' to Resource instead of Content and this problem should go away. I was able to reproduce your problem this way and it works correctly when set as a Resource.
Xaml.VB
Call the Image from Application folder and Design Page
Private Sub LoadImages()
Dim strUri As String
strUri = AppDomain.CurrentDomain.BaseDirectory() & "\NavigationImages\settingsicon.png"
Image2.Source = New BitmapImage(New Uri(strUri))
End Sub
Page load in Xaml.VB
Call LoadImages()
Xaml Design Page
Image Name="Image2"Height="32" HorizontalAlignment="Left"

Resources