Call a function from UserControl - UWP C#

问题:

I'm using below code for rotate an image in my app (using UserControl). But it shows an error ConvertToBitmapImage was not found in type ImageControl. How can I resolve it?

The ImageControl XAML:

<UserControl x:Class="App1.ImageControl" ...>
    <Image RenderTransformOrigin="0.5,0.5"
           Source="{x:Bind ConvertToBitmapImage(UriPath), Mode=OneWay}"
           Stretch="UniformToFill">
        <Image.RenderTransform>
            <CompositeTransform Rotation="{x:Bind Angle, Mode=OneWay}" />
        </Image.RenderTransform>
    </Image>
</UserControl>

The ImageControl Code Behind:

public string UriPath
{
    get => (string)GetValue(UriPathProperty);
    set => SetValue(UriPathProperty, value);
}

public static readonly DependencyProperty UriPathProperty = DependencyProperty.Register("UriPath", typeof(string), typeof(ImageControl), new PropertyMetadata(default(string)));

public double Angle
{
    get => (double)GetValue(AngleProperty);
    set => SetValue(AngleProperty, value);
}

public static readonly DependencyProperty AngleProperty = DependencyProperty.Register("Angle", typeof(double), typeof(ImageControl), new PropertyMetadata(default(double)));

public BitmapImage ConvertToBitmapImage(string path) => new BitmapImage(new Uri(BaseUri, path));

回答1:

You can not use {x:Bind} to bind a Function until Windows 10, version 1607. See the Functions in binding paths Note part:

To use functions with {x:Bind}, your app's minimum target SDK version must be 14393 or later. You can't use functions when your app targets earlier versions of Windows 10.

So you should either change your app min target version to 14393 or later, or don't use the x:bind function.