# AUR0750

## Error Message

`AUR0750: view.ref is not supported. If you are migrating from v1, this can be understood as the controller.`

## Description

This error indicates that code is attempting to access the `ref` property on a `View` instance created by the rendering engine. This `view.ref` API existed in Aurelia v1 but has been removed in Aurelia v2.

## Cause

The primary cause is code (often migrated from Aurelia v1 or based on v1 examples) that directly tries to use `view.ref`. In Aurelia v1, `view.ref` often provided a reference to the underlying host element or component instance associated with the view.

## Solution

The direct replacement or equivalent functionality in Aurelia v2 depends on what `view.ref` was being used for in the original v1 code:

1. **Accessing the Controller/View Model:** If `view.ref` was used to get the component instance (view model), you should now typically access the controller associated with the view. The controller holds the component instance and provides methods for managing the component's lifecycle and state. How you get the controller depends on the context, but often it's available directly where the view is being manipulated (e.g., in template controllers like `repeat`, `if`, or custom attributes managing views).
2. **Accessing the Host Element:** If `view.ref` was used to get the host DOM element of the component associated with the view, you should access the `controller.host` property.
3. **Using `ref` Attribute:** For accessing specific DOM elements within a component's template, the standard approach in Aurelia v2 is to use the `ref` attribute in the template (e.g., `<div ref="myDivElement">`) and declare a corresponding property in the view model (`myDivElement: HTMLDivElement;`).

Review the v1 code that used `view.ref` and determine its purpose. Then, adapt the code to use the appropriate Aurelia v2 mechanism, most likely involving the `controller` associated with the view or the `ref` attribute for specific elements.

## Example (Conceptual)

**Aurelia v1 (Illustrative):**

```typescript
// In some custom attribute or logic dealing with views
let view = viewFactory.create();
// ... attach view ...
let componentInstance = view.ref; // Accessing the component instance ( Hypothetical v1 usage )
let hostElement = view.ref; // Accessing the host element ( Hypothetical v1 usage )
```

**Aurelia v2 Equivalent:**

```typescript
// In some custom attribute or logic dealing with views
let view = viewFactory.create();
let controller = view.controller; // Get the controller associated with the view

// ... attach view ...

// Accessing the component instance (View Model)
let componentInstance = controller.viewModel;

// Accessing the host element
let hostElement = controller.host;

// If needing a specific element within the view's template:
// Template: <input ref="emailInput">
// VM: emailInput: HTMLInputElement;
// Access: componentInstance.emailInput
```

## Debugging Tips

* Locate the code that triggers the error, specifically the access to `.ref` on a view object.
* Understand the original intent of using `view.ref` in the v1 context.
* Identify the controller associated with the view in your v2 code.
* Use `controller.viewModel` to access the component instance or `controller.host` to access the host element.
* Use the `ref` attribute in templates for accessing specific internal elements.