模板解析错误:Invocation of property 'ParentCategoryID' in HopeCMS.TemplateUtil.HopeTag threw exception System.NullReferenceException : Object reference not set to an instance of an object. at NVelocity.Runtime.Parser.Node.ASTReference.execute(Object o, InternalContextAdapter context) at NVelocity.Runtime.Parser.Node.ASTReference.value_Renamed(InternalContextAdapter context) at NVelocity.Runtime.Parser.Node.ASTNENode.evaluate(InternalContextAdapter context) at NVelocity.Runtime.Parser.Node.ASTExpression.evaluate(InternalContextAdapter context) at NVelocity.Runtime.Parser.Node.ASTIfStatement.render(InternalContextAdapter context, TextWriter writer) at NVelocity.Runtime.Parser.Node.SimpleNode.render(InternalContextAdapter context, TextWriter writer) at NVelocity.Template.Merge(IContext context, TextWriter writer) at HopeCMS.TemplateUtil.TemplateHandler.GetTagProcessStr(String sTagName) at HopeCMS.TemplateUtil.TemplateHandler.BuildTemplate(String temFile)