WrapPanel (CODE)

The panel most similar to StackPanel is WrapPanel. During the years that the Windows Presentation Foundation was being designed and created, the WrapPanel actually preceded the StackPanel. The WrapPanel displays rows or columns of elements and automatically wraps to the next row (or column) if there's not enough room. It sounds quite useful, but it turned out that developers were mostly using WrapPanel without the wrapping. These developers didn't know it at the time, but they really wanted a StackPanel.

WrapPanel is useful when you need to display an unknown number of items in a two-dimensional area. (Think of it as Windows Explorer in non-detail view.) It's likely that all these items will be the same size. WrapPanel doesn't require that, but it has ItemHeight and ItemWidth properties that you can use to enforce uniform height or width. The only other property that WrapPanel defines is Orientation, which you use the same way as for StackPanel.

It is difficult to imagine an application of WrapPanel that doesn't also involve ScrollViewer.  Lets see example with both:

//INSIDE CONSTRUCTOR OF WINDOWS
{
       Title = "Explore Directories";

       ScrollViewer scroll = new ScrollViewer();
       Content = scroll;

       WrapPanel wrap = new WrapPanel();
       scroll.Content = wrap;

       wrap.Children.Add(new FileSystemInfoButton());
}

I named FileSystemInfoButton for the FileSystemInfo object in System.IO. The two classes that derive from FileSystemInfo are FileInfo and DirectoryInfo. If you have a particular object of type FileSystemInfo, you can determine whether it refers to a file or to a directory by using the is operator.

The FileSystemInfoButton class derives from Button and stores a FileSystemInfo object as a field. The class has three constructors. The single-argument constructor is the one used most. It requires an argument of type FileSystemInfo, which it stores as a field. The constructor sets the button's Content to the Name property of this object. That's either the name of a directory or the name of a file. If this object is a DirectoryInfo, the text is bolded.

The parameterless constructor is used only when the program starts up and the window adds the first child to the WrapPanel or any other panel. The parameterless constructor passes a DirectoryInfo object for the My Documents directory to the single-argument constructor.

 

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