Cannot get External URL from UploadFileWithIDSelector object - acumatica

Question

I am trying to create an action that opens a tab, inserts an uploaded file's external URL into the tab, and navigates to that URL just like as if a user clicked the Files button and then clicked one of the File's titles and it opened up the tab with the contents of the file.
Here is the code I used to get the External Link. Please note that I have the FileID stored as an extension column in the InventoryItem table for this example:
PXView item = Base.Views["Item"];
InventoryItem item = PXSelect<InventoryItem, Where<InventoryItem.inventoryCD,
Equal<Current<InventoryItem.inventoryCD>>>>
.Select(Base, Base.Views["Item"].Cache.Current);
InventoryItemExt itemext = item.Cache.GetExtension<InventoryItemExt>(item);
UploadFileWithIDSelector fileInfo = PXSelect<UploadFileWithIDSelector,
Where<UploadFileWithIDSelector.fileID,
Equal<Current<PX.Objects.IN.InventoryItemExt.usrDefaultSpecID>>>
.Select(Base, itemext.UsrDefaultSpecID);
I then try to execute the following code to open the page using the ExternalLink:
throw new PXRedirectToUrlException(fileInfo.ExternalLink, "");
This results in the following error:
Object reference not set to an instance of an object.
Is the DAC unable to directly get the external link? Is there any way to fix this so it retrieves the external link? Is there another (possibly simpler) way to retrieve the external link of an uploaded file?
Thanks

Answer 1

You should be able to redirect to the file with this syntax:
throw new PXRedirectToUrlException(PXRedirectToFileException.BuildUrl(fileInfo.fileID), "");
Consider using this syntax to redirect since you don't need a message:
throw new PXRedirectToFileException(fileInfo.fileID, true);