# pqLoadDataReaction in custom application
**URL:** https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230
**Category:** Development
**Created:** [March 20, 2022, 11:55am UTC](https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230 "2022-03-20T11:55:37Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@fvitello](https://discourse.paraview.org/u/fvitello)
#### Post date: [March 20, 2022, 11:55am UTC](https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230/1 "2022-03-20T11:55:37Z")
Hi all,
i am trying to implement my first custom application based on paraview and I have defined a pqLoadDataReaction linked to a QAction.
`pqLoadDataReaction* dataLoader = new pqLoadDataReaction(ui.actionOpen);`
When I execute my app, triggering the action I obtain the following error:
`**Assertion failed: (filters.isEmpty()), function loadData, file pqLoadDataReaction.cxx, line 86.**`
I think it is related to an empty response from readerFactory-\>GetSupportedFileTypes.
How I can define the supported file types of my application?
---
### Author:  [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [March 20, 2022, 12:56pm UTC](https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230/2 "2022-03-20T12:56:18Z")
Try calling `pqApplicationCore::updateAvailableReadersAndWriters` explicitly during application startup. I suspect for some reason it’s being called during initialization.
---
### Author:  [@fvitello](https://discourse.paraview.org/u/fvitello)
#### Post date: [March 20, 2022, 3:52pm UTC](https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230/3 "2022-03-20T15:52:45Z")
I have solved with
```auto
readerFactory->RegisterPrototype("sources", "XMLPolyDataReader");
```
---
### Author:  [@fvitello](https://discourse.paraview.org/u/fvitello)
#### Post date: [March 20, 2022, 5:05pm UTC](https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230/4 "2022-03-20T17:05:13Z")
I am now trying to visualize data with a custom reader for Fits format files with this code:
```auto
pqObjectBuilder *builder = pqApplicationCore::instance()->getObjectBuilder();
pqDataRepresentation *drep = builder->createDataRepresentation(
this->originSource->getOutputPort(0), this->view);
vtkSMPropertyHelper(drep->getProxy(), "Representation").Set(VTK_SURFACE);
drep->getProxy()->UpdateVTKObjects();
this->view->resetDisplay();
this->view->render();
```
But I obtain this error:
**vtkPVCompositeRepresentation (0x16f473ff0): No representation was found with Name: 2**
UPDATE: I realised that only Outline representation is available, How can I create other type of representation?
---
### Author:  [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [March 21, 2022, 11:41am UTC](https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230/5 "2022-03-21T11:41:29Z")
“Representation” is a string property. The values it accepts are the string e.g. `"Surface"`, `"Wireframe"`, etc. and not enums.
---
### Author:  [@fvitello](https://discourse.paraview.org/u/fvitello)
#### Post date: [March 21, 2022, 1:50pm UTC](https://discourse.paraview.org/t/pqloaddatareaction-in-custom-application/9230/6 "2022-03-21T13:50:42Z")
Thanks