Razor PageHandler PartialViewResult Model Type mismatch

Question

I have a PartialView with a Model of type Machine that renders a row in a table.

@model GPT.Core.Models.Machine
<tr>
  @* 
    some html 
  *@
</tr>

This partial view is working fine when rendered in a loop in the parent view like this:

@foreach (var machine in pl.Machines)
{
  // some code
  // ...
  await Html.RenderPartialAsync("_MachineTableRow", machine);
}

I'm using a AJAX-Request on the client to update some data and want to update the corresponing data row as well thereafter. So my AJAX-request calls

public async Task<PartialViewResult> OnPostAnalyzeMachineJournalAsync()
{
    // some code
    // ...
    var machine = GetUpdateMachinePseudoMethod();
    return Partial("_MachineTableRow", machine);
}

But this throws an exception:

System.InvalidOperationException: The model item passed into the ViewDataDictionary is of type 'GPT.Core.Models.Machine', but this ViewDataDictionary instance requires a model item of type 'GPT.Web.Pages.IndexModel'.

I'm not sure to which ViewDataDictionary this exception is refering. But even if it doesn't make sense to me and just out of curiosity, I provided the IndexModel that is mentioned by the exception.

await Html.RenderPartialAsync("_MachineTableRow", this);

Then there is anoter exception telling my exactly the same thing the other way round, which leaves me completely confused now:

System.InvalidOperationException: The model item passed into the ViewDataDictionary is of type 'GPT.Web.Pages.IndexModel', but this ViewDataDictionary instance requires a model item of type 'GPT.Core.Models.Machine'.

Can anyone tell why it isn't working when I pass a Machine instance like it is defined in the partial cshtml file and like it is also mentioned in the second exception? What am I missing here?

Answer 1

Ok, further investigation revealed this:

Github Bugfix

Seems this is really a Bug in .netcore 2.2 and has been fixed in .netcore 3.0 I'll give the RC version a try and will report back if this was successful.

Edit: After updating the target framework to .netcore 3.0, the code works as expected and accepts the provided model.