# OnMouseDown(MouseDownEvent)

> Called on mouse down event.

## Definition

* **Type:** Method
* **Namespace:** [UnityEditor.Experimental.GraphView](/engine/6000.7/script-reference/unityeditor/experimental/graphview.md)
* **Assembly:** UnityEditor

```csharp
protected void OnMouseDown(MouseDownEvent e)
```

### Parameters

**** (\[MouseDownEvent]\(/engine/6000.7/script-reference/unityengine/uielements/mousedownevent)): The event.