.Net Core Renderer: Retrieving Related fields throws exception when no item is selected

In projects with enabled setting "Map related properties as objects" in Settings/Advanced/WebServices. In a custom view template, when trying to render a related media field (image) or related data field with this type of code: var field = item.GetValue("FieldName"); if image is not selected, the above code throws an exception: Unable to cast object of type 'Newtonsoft.Json.Linq.JValue' to type 'Newtonsoft.Json.Linq.JObject'.

Aug 27, 2024
Knowledge

Title

URL Name

net-core-renderer-retrieving-related-fields-throws-exception-when-no-item-is-selected

Article Number

000264762

Environment

Product: Sitefinity Version: 13.3, 14.0, 14.4, 15.0, 15.1, 15.2 OS: All supported OS versions Database: All supported Microsoft SQL Server versions

Question/Problem Description

In a custom SitefinityContentList view template. Trying to render a related media image with this type of code:

var image = item.GetValue("ImageFieldName");

ImageFieldName is the name of the field in the database, and it is configured to be only 1 image.

When the field is populated(there are selected image), the template is working.

If the image is not selected, there is an exception in the code:
Unable to cast object of type 'Newtonsoft.Json.Linq.JValue' to type 'Newtonsoft.Json.Linq.JObject'.

The same is valid for Related Data field.

Steps to Reproduce

1. In Settings/Advanced/WebServices - enable "Map related properties as objects" 2. Create dynamic module and add Related Media field (with limitation to upload only 1 image) 3. Create custom view for the Content List Widget as per below documentation in Sitefinity Documentation -> ASP.NET Core Renderer -> Extend and develop widgets -> Create custom views for the Content list widget: https://www.progress.com/documentation/sitefinity-cms/create-custom-views-for-the-content-list-widget 4. In the view try to retrieve the Related Media field for example: @foreach (var item in Model.Items) { var image = item.GetValue<ImageDto>("ViewImage"); string imageUrl = image != null ? image.ThumbnailUrl : ""; <div> <img src="@imageUrl"/> </div> } Result: When the field has an image the image is retrieved successfully, but when the field doesn't have selected image the below method throws exception. "var image = item.GetValue<ImageDto>("ViewImage");" Exception: "Unable to cast object of type 'Newtonsoft.Json.Linq.JValue' to type 'Newtonsoft.Json.Linq.JObject'"

Clarifying Information

The issue reproduces also for Related Data fields.

Error Message

Unable to cast object of type 'Newtonsoft.Json.Linq.JValue' to type 'Newtonsoft.Json.Linq.JObject'

Defect Number

533725

Enhancement Number

Cause

The issue is caused by a bug in Sitefinity

Resolution

Sitefinity Patch 15.1.8327

Refer to Knowledge Base Article How to update Sitefinity to hotfix, internal build or a patch for instructions on how to download and install the fix.

Workaround

Disable setting in Settings/Advanced/WebServices - "Map related properties as objects".

Need to have in mind if there is code in views, which is calling item.GetValue<ImageDto>("ImageField"); for example, the type parameter has to be refactored to ImageDto[] or List<ImageDto>.

The same goes for Related Data fields.

Notes

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Last Modified Date

2/3/2025 9:39 AM

.Net Core Renderer: Retrieving Related fields throws exception when no item is selected

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