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Customizing the ExplorerBarView

Setting Content Size Mode

The RadPageView’s Explorer Bar mode supports three different content size modes for the expanded pages:

  • FixedLength: implies that all expanded pages have a length, defined by the PageLength property. By default, the value of this property is 300 pixels. You can set this property in the Visual Studio Designer by selecting the corresponding RadPageViewPage instance and setting the PageLength property in the Property Grid. If there is not enough space for the items and the expanded pages, a scrollbar is shown in the control.

  • AutoSizeToBestFit: implies that the expanded page is sized according to the content. In other words, the smallest bounding rectangle of all controls in the page is calculated and used to define the bounds of the page.

  • EqualLength: implies that the size of all expanded pages is equal. The size is calculated based on the remaining space after the layout has finished ordering the items. The available space is equally distributed to all expanded pages.

To define how expanded pages are sized, you should set the ContentSizeMode property of the RadPageViewExplorerBarElement class. When in PageViewMode.ExplorerBar, the ViewElement property of the RadPageView control returns an instance of this class, so you should simply cast it to the appropriate type and set the property as the code snippet below demonstrates:


RadPageViewExplorerBarElement explorerBarElement = (this.radPageView1.ViewElement as RadPageViewExplorerBarElement);
explorerBarElement.ContentSizeMode = ExplorerBarContentSizeMode.EqualLength;

Dim explorerBarElement As RadPageViewExplorerBarElement = (TryCast(Me.radPageView1.ViewElement, RadPageViewExplorerBarElement))
explorerBarElement.ContentSizeMode = ExplorerBarContentSizeMode.EqualLength

If you choose to use the FixedLength size mode and consequently wish to define length to a given page, you can do this the following way:


this.radPageViewPage1.PageLength = 430;

Me.radPageViewPage1.PageLength = 430

Setting Stack Position

The RadPageView’s PageViewMode.ExplorerBar supports two stack positions:

  • Top

  • Left

Expanding/Collapsing Pages

To expand or collapse a page, you should simply click on its item. You can also do this programmatically by setting the IsContentVisible property defined in the RadPageViewPage class:

Setting the IsContentVisible property

this.radPageViewPage1.IsContentVisible = true;

Me.radPageViewPage1.IsContentVisible = True

If you wish to have a page initially expanded, you can set the IsContentVisible property in the Visual Studio’s Designer as well.

Using the Explorer Bar Events

RadPageView exposes four specific events fired when the state of a page is about to change, and when it is changed. It is important to note that these events are only relevant to the ExplorerBar mode:

  • PageExpanding: It is fired each time a page is about to be expanded. It is possible to cancel the expansion of the page by modifying the Cancel property of the event arguments in the event handler of this event.

  • PageExpanded: It is fired each time a page has been expanded.

  • PageCollapsing: It is fired each time a page is about to be collapsed. It is possible to cancel the expansion of the page by modifying the Cancel property of the event arguments in the event handler of the event.

  • PageCollapsed: It is fired each time a page has been collapsed.


The PageViewMode.ExplorerBar supports scrolling when the expanded content exceeds the bounds of the control. In this case, a scrollbar is automatically shown thus allowing the user to scroll and view each expanded page.

The PageViewMode.ExplorerBar also automatically scrolls to an item when it is selected. The ScrollToItem method is internally used. This method is also part of the RadPageViewExplorerBarElement's API and can be accessed in case it is needed to scroll to a given item programmatically. The following code snippet demonstrates the usage of the ScrollToItem method:


RadPageViewExplorerBarItem item = this.radPageViewPage1.Item as RadPageViewExplorerBarItem;

Dim item As RadPageViewExplorerBarItem = TryCast(Me.radPageViewPage1.Item, RadPageViewExplorerBarItem)

See Also