taskrun with getpropertyvalue gives nullrefexception - Using Umbraco and getting started

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Ian 23 posts 113 karma points

Mar 28, 2016 @ 09:51

Task.Run with GetPropertyValue gives NullRefException

Hi lovely umbraco community :) I wonder if anyone has seen this / if its by design:

I have a NullReferenceException being generated when I try to use GetPropertyValue within a method called from Task.Run, within a surface controller.

The Task.Run part looks like this:

Task.Run(() => {
  SendInternalEmail(model); //do async
});

And the SendInternalEmail method roughly like this:

private void SendInternalEmail(MyModel model)
{
  //NOTE: the GetPropertyValue throws a NullReferenceException when this method is run async!
  //-even though the node is correctly found and the prop can be seen on it with a value
  var node = Umbraco.TypedContent(model.NodeId); 
  string emailAddress = node.GetPropertyValue<string>("internalEmailAddress");

The umbraco logs show this (confidential code replaced with mycode):

 2016-03-28 10:29:19,663 [P10052/D15/T471] ERROR <mycode> - Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
   at Umbraco.Web.Templates.TemplateUtilities.ParseInternalLinks(String text, Boolean preview)
   at Umbraco.Web.PropertyEditors.ValueConverters.TextStringValueConverter.ConvertDataToSource(PublishedPropertyType propertyType, Object source, Boolean preview)
   at Umbraco.Web.PublishedCache.XmlPublishedCache.XmlPublishedProperty.<.ctor>b__0()
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at Umbraco.Web.PublishedCache.XmlPublishedCache.XmlPublishedProperty.<.ctor>b__1()
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at Umbraco.Web.PublishedPropertyExtension.GetValue[T](IPublishedProperty property, Boolean withDefaultValue, T defaultValue)
   at Umbraco.Web.PublishedContentExtensions.GetPropertyValue[T](IPublishedContent content, String alias)
   at <mycode>.SendInternalEmail(MyModel model) in C:\Development\<mycode>:line 71

Any one seen this? Am I missing something? Im using umbraco v7.4.

tia Ian

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David Armitage 508 posts 2078 karma points

Jun 09, 2016 @ 05:25
0
Hi,

I am not sure if it is related but since moving to Umbraco 7.4 I have experience a few similar problems. My problems have mainly been running umbraco saves within the background tasks. The gets I haven't really noticed any problems but I haven't looked at the logs in a while.

Basically the problems I've been having is the context is missing and when I attempt to update / save something into umbraco within a background task it fails.

I googled around and found an hack to fake the context.
```
//fake the context to get around an error
//exception details: Value cannot be null.Parameter name: httpContext
HttpContext.Current = new HttpContext(new HttpRequest(null, "https://www.google.com", null), new HttpResponse(null));
```
I am not sure if your issues are caused by the same thing but I have a feeling they might be. Try adding this block of code before dealing with the Umbraco gets and sets. See if it helps.

Kind Regards

David
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Mark Wemekamp 73 posts 385 karma points

Feb 07, 2017 @ 16:20

0

Have you managed to fix this problem?

I'm currently experiencing the exact same problem. Running a task with a GetPropertyValue call in it returns a NullReferenceException

I've tried adding the fake HttpContext on a few places, but no luck so far.

Kind regards,

Mark

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Ian 23 posts 113 karma points

Feb 08, 2017 @ 08:19

0

Hi Mark

no I didnt fix it, I just worked around it by getting all the properties I needed before the Task.Run call and just passing them in.

Ian

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Tom 3 posts 73 karma points

Mar 04, 2019 @ 22:05
0
Hey, I know this is an old post but I ran into a similar issue and was able to resolve it. I passed reference to the the current Umbraco context to the async function and then in that function I got the property like so:
```
IPublishedProperty myProp = myNode.Properties.Where(x => x.PropertyTypeAlias == "myPropertyAlias").First();
string myString = (string)myProp.DataValue;
```
Hope this helps somebody.
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Georgios Rovolis 9 posts 80 karma points

Aug 16, 2019 @ 10:53

0

Legend! Works fine any idea if the value is an Id or Udi, how I can access that entity as well?

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