Binding这个类包含以下几个常用的属性：
ElementName: Gets or sets the name of the elements to use as the binding source object. [Default is null]
Source: Gets or sets the object to use as the binding source.
RelativeSource: Gets or sets the binding source by specifying its location relative to the position of the binding target.
Converter: Gets or sets the converter to use.
Mode: Gets or sets a value that indicates the direction of the data flow in the binding.
Path: Gets or sets the path to the binding source property.
StringFormat: Gets or sets a string that specifies how to format the binding if it displays the bound value as a string.(Inherited from BindingBase.)
Only one of the three properties, ElementName, Source, and RelativeSource, should be set for each binding, or a conflict might occur.
By default, bindings inherit the data context specified by the DataContext property
Path is the default property of a binding. {Binding PropertyName} 等价于 {Binding Path=PropertyName}
{Binding} is equivalent to {Binding Path=.}, which binds to the current source
参考链接：
https://msdn.microsoft.com/en-us/library/system.windows.data.binding(v=vs.110).aspx
https://msdn.microsoft.com/en-us/library/ms750413.aspx
https://msdn.microsoft.com/en-us/library/ms746695(v=vs.110).aspx
https://msdn.microsoft.com/en-us/library/ms752347(v=vs.110).aspx
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