Checks whether this SVG document is the global null instance.
public virtual bool IsNull { get; }
true if this SvgDocument object is the global null instance; otherwise, false.
In some instances, an SvgDocument object that is not initialized (that is, the object is null) is required. For instance, when serializing raster images to a system that do not support a true null value. In this case, SvgDocument.NullInstance can be used to represent an SvgDocument that has not been initialized (but is not null). IsNull can be used to test whether an SvgDocument object is the null instance.
SvgDocument.NullInstance is a global object and calling any other member besides IsNull will throw an exception. The one exception is calling Dispose which will be ignored.
Note that calling svgDocumentObject.IsNull is the equivalent of svgDocumentObject == SvgDocument.NullInstance.