我已将scrollviewer添加到我的WPF应用程序中但是当我调整大小时我仍然看不到控件
<ScrollViewer>
<GroupBox Header = "Add Member" FontFamily="Calibri" FontWeight="Bold" FontSize="24" Height="500">
<Grid>
<RadioButton Content = "Female" FontSize="16" FontWeight="Normal" TabIndex="4" Margin="651,335,0,105"/>
</Grid>
</GroupBox>
</ScrollViewer>
我错过了什么?