我会给scrollviewer一个特定的高度而不是auto ie（800）。  如果文本仍然在顶部稍微剪切，我还会尝试在文本块上设置上边距

I would give the scrollviewer a specific height instead of auto ie (800).  I would also try setting a top margin on the textblock if the text is still cut off a little at the top