我带了一个文本框
<TextBox Height="218" HorizontalAlignment="Stretch" Margin="0,56,0,0" Name="txtBox" VerticalAlignment="Top" TextWrapping="Wrap"
Text="" GotFocus="txtBox_GotFocus" TextChanged="txtBox_TextChanged" IsTabStop="True"
IsEnabled="True" IsHitTestVisible="True" VerticalScrollBarVisibility="Auto" Background="White" FontFamily="Tahoma" />
现在,当我在文本框中输入大量文本时,文本会自动向上滚动.我想显示一个滚动条,用户可以浏览整个文本.这该怎么做.