WPF Image: Getting the Actual Size after multiple Source updates

Question

I'm updating the Source of an Image control based on a ComboBox selection.

After the Image Source is updated, I need to read the ActualWidth and ActualHeight of the Image

I managed this to work the first time the dialog opens using the Loaded event of the Image control, but this event doesn't obviously raise every time i update the Source.

Is there any way to get the Actual Size of the images loaded into the control after each Source update?

osMike osMike · Accepted Answer · 2011-12-19T18:02:13

You can try to use the image sourceupdated event, but i do not always have any luck using this.

A better solution, depending on your source is to add a handler for when it is loaded.

you can try something like this:

Dim src As BitmapImage = New BitmapImage()
src.BeginInit()
src.UriSource = tURI
src.CacheOption = BitmapCacheOption.OnLoad
src.EndInit()
imgImage.SetCurrentValue(Image.SourceProperty, src)
AddHandler src.DownloadCompleted, AddressOf ImageDownloadCompleted

then you can write the code for ImageDownloadCompleted to get the actual height and width of the image.

To get actual widths, I use the width of the source image and not the image control, as shown below:

Sub ImageDownloadCompleted(sender As Object, e As System.EventArgs)
    Dim src As BitmapImage
    Dim dwidth as Double
    Dim dheight as Double

    src = DirectCast(sender, BitmapImage)
    dwidth = src.Width 
    dheight = src.Height
    RemoveHandler src.DownloadCompleted, AddressOf ImageDownloadCompleted
End Sub

WPF Image: Getting the Actual Size after multiple Source updates

1 Answers