占位符。由树形网格控件代替。
这些控件之一是指定为占位符控件。
One of these controls is designated as a placeholder control.
子母版页通常会包含一些内容控件，这些控件将映射到父母版页上的内容占位符。
The child master page typically contains content controls that are mapped to content placeholders on the parent master page.
应用推荐