Testing image crops existence with Razor in Umbraco - image

Question

I have created some Razor code to output images onto a page if the exist. It is detailed below and contains some simple checks to prevent rendering a blank list item. The site has gone live and works fine. The client then deleted the image from the media folder within Umbraco, meaning my node had a valid image assigned but the image just didn't exists. I got the following exception:
'string' does not contain a definition for 'crops'
How do I deal with this?
#using umbraco.MacroEngines;
#inherits umbraco.MacroEngines.DynamicNodeContext
#using umbraco.presentation.nodeFactory
#using umbraco.cms.businesslogic.media
<ul>
#foreach (dynamic client in #Model.Children)
{
var image = Model.MediaById(client.Logo);
var crops = image.imageCropper.crops;
<li>
<h2><span>#client.Name</span></h2>
#if (crops != null || crops.GetType().ToString() != "System.String")
{
<span class="itemImage">
<img src="#crops.Find("#name", "cropname").url" alt="#client.Name" />
</span>
}
</li>
}
</ul>

Answer 1

In this case you'll probably need to do a type check. I believe the MediaById method should return a DynamicNode if it's valid, so something like the following should work:
if(image.GetType() == typeof(DynamicNode))
{
...
}

Answer 2

I was getting this issue. What I found is that the Model.MediaById(imageid) call would throw an exception if the Media had been deleted (and had already been picked in the past).
So I setup my test like this:
dynamic mainMediaImage = new DynamicNull();
try
{
mainMediaImage = Model.MediaById(related.eventMainImage);
}
catch(Exception e)
{
<p style='display: none;'>#e.Message</p>
}
var cropUrl = "";
if(mainMediaImage.GetType() == typeof(DynamicMedia))
{
cropUrl = GetImageCropperUrl(Model.MediaById(related.eventMainImage).crops, "List Image");
}
I still get the error, but it doesn't display to the user.
I found it would never get to my DynamicMedia check so I had to add the try...catch() around the call or else to entire Macro would fail.