IUIAnimationVariableChangeHandler::OnValueChanged method (uianimation.h)

Handles events that occur when the value of an animation variable changes.

This method receives updates as DOUBLE values.
To receive updates as INT32 values, use the IUIAnimationVariableIntegerChangeHandler::OnIntegerValueChanged method.

Syntax

HRESULT OnValueChanged(
  [in] IUIAnimationStoryboard *storyboard,
  [in] IUIAnimationVariable   *variable,
  [in] DOUBLE                 newValue,
  [in] DOUBLE                 previousValue
);

Parameters

[in] storyboard

The storyboard that is animating the animation variable specified by the variable parameter.

[in] variable

The animation variable that has been updated.

[in] newValue

The new value of the animation variable.

[in] previousValue

The previous value of the animation variable.

Return value

If the method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. See Windows Animation Error Codes for a list of error codes.

Remarks

By default, a call made in a callback method to any other animation method results in the call failing and returning UI_E_ILLEGAL_REENTRANCY. However, there are exceptions to this default. The following methods can be successfully called from OnValueChanged:

• IUIAnimationVariable::GetValue
• IUIAnimationVariable::GetFinalValue
• IUIAnimationVariable::GetPreviousValue
• IUIAnimationVariable::GetIntegerValue
• IUIAnimationVariable::GetFinalIntegerValue
• IUIAnimationVariable::GetPreviousIntegerValue
• IUIAnimationVariable::GetCurrentStoryboard
• IUIAnimationManager::GetVariableFromTag
• IUIAnimationManager::GetStoryboardFromTag
• IUIAnimationStoryboard::GetTag
• IUIAnimationVariable::GetTag

Requirements

See also

IUIAnimationVariable::GetPreviousValue

IUIAnimationVariable::GetValue

IUIAnimationVariable::SetVariableChangeHandler

IUIAnimationVariableChangeHandler

IUIAnimationVariableIntegerChangeHandler::OnIntegerValueChanged