In XAML markup, specifies a default mode for x:Bind.
x:DefaultBindMode is available starting in Windows 10, version 1607 (Anniversary Update), SDK version 14393.
XAML attribute usage
<object x:DefaultBindMode="OneTime \| OneWay \| TwoWay" .../>
x:Bind has a default mode of OneTime. This was chosen for performance reasons, as using OneWay causes more code to be generated to hookup and handle change detection. You can use x:DefaultBindMode to change the default mode for x:Bind for a specific segment of the markup tree. The specified mode applies to any x:Bind expressions on that element and its children, that do not explicitly specify a mode as part of the binding.