IUIAnimationVariableChangeHandler::OnValueChanged method

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

storyboard [in]

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

variable [in]

The animation variable that has been updated.

newValue [in]

The new value of the animation variable.

previousValue [in]

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

IUIAnimationVariableChangeHandler

IUIAnimationVariable::GetPreviousValue

IUIAnimationVariable::GetValue

IUIAnimationVariable::SetVariableChangeHandler

IUIAnimationVariableIntegerChangeHandler::OnIntegerValueChanged