stem.string" target="_blank">System<span id="LST44F33E75_6"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST44F33E75_6?cs=.|vb=.|cpp=::|nu=.|fs=.");</script>String</a><br />用户卡片的背景图片</dd><dt><span class="parameter">bonus</span> (Optional)</dt><dd>类型：<a href="https://docs.microsoft.com/dotnet/api/system.nullable-1" target="_blank">System<span id="LST44F33E75_7"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST44F33E75_7?cs=.|vb=.|cpp=::|nu=.|fs