SlipBehavior.Slip은 역전, 가속, 감속되지 않거나 Duration으로 RepeatBehavior가 지정되지 않은 루트 ParallelTimeline에서만 지원됩니다.
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English version
SlipBehavior.Slip is supported only on root ParallelTimelines that do not reverse, accelerate, decelerate, or have a RepeatBehavior specified as a Duration.
.Net Framework