![](dotnetdiagramimages/MESCIUS_ActiveReports_Core_Rendering_GrapeCity_DataVisualization_Chart__NullDataField.png)
'宣言
Public Class _NullDataField Inherits _BaseDataField Implements IDataField, GrapeCity.DataVisualization.Chart.IEquatable(Of IDataField), INullDataField
public class _NullDataField : _BaseDataField, IDataField, GrapeCity.DataVisualization.Chart.IEquatable<IDataField>, INullDataField
System.Object
GrapeCity.DataVisualization.Chart._BaseDataField
GrapeCity.DataVisualization.Chart._NullDataField