InputManager.PreProcessInput Event

Occurs when the InputManager starts to process the input item.

Namespace:  System.Windows.Input
Assembly:  PresentationCore (in PresentationCore.dll)

'Declaration
Public Event PreProcessInput As PreProcessInputEventHandler

A filter is any code that listens to PreProcessInput or PostProcessInput. Filters can modify the input staging area.

The handlers attached to PreProcessInput are invoked in reverse order so that handlers added by the users are invoked before handlers in the system.

Calling Cancel on the PreProcessInputEventArgs passed to the PreProcessInputEventHandler will cancel the processing of the input.

Input is processed in WPF in the follow stages:

  1. Pre-process stage. The input manager raises the PreProcessInput event.

  2. Pre-notify stage. The input manager raises the PreNotifyInput event.

  3. The WPF input event or events are raised.

  4. Post-notify stage. The input manager raises the PostNotifyInput event.

  5. Post-process stage. The input manager raises the PostProcessInput event.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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