return null if component was not read

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFAdasType.cs

@@ -17,6 +17,10 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var adas = inputData.JobInputData.Vehicle.ADAS;
+
+			if (adas == null)
+				return null;
+
 			return new XElement(_vif + XMLNames.Vehicle_ADAS,
 				new XElement(_vif + XMLNames.Vehicle_ADAS_EngineStopStart, adas.EngineStopStart),
 				new XElement(_vif +  XMLNames.Vehicle_ADAS_EcoRollWithoutEngineStop, adas.EcoRoll == EcoRollType.WithoutEngineStop),

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFAngleDriveType.cs

@@ -17,6 +17,8 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var angelDrive = inputData.JobInputData.Vehicle.Components.AngledriveInputData;
+			if (angelDrive == null)
+				return null;
 
 			return new XElement(_vif + XMLNames.Component_Angledrive,
 					new XElement(_vif + XMLNames.ComponentDataWrapper,

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFAuxiliaryType.cs

@@ -21,6 +21,8 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var aux = inputData.JobInputData.Vehicle.Components.BusAuxiliaries;
+			if (aux != null)
+				return null;
 
 			return new XElement(_vif + XMLNames.Component_Auxiliaries,
 					new XElement(_vif + XMLNames.ComponentDataWrapper,

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFAxleWheelsType.cs

@@ -16,6 +16,9 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var axleWheels = inputData.JobInputData.Vehicle.Components.AxleWheels;
+			if (axleWheels != null)
+				return null;
+
 			return new XElement(_vif + XMLNames.Component_AxleWheels,
 				new XElement(_vif + XMLNames.ComponentDataWrapper,
 					new XAttribute(_xsi + "type", "v2.0:AxleDataDeclarationType"),

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFAxlegearType.cs

@@ -17,7 +17,9 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var axleGear = inputData.JobInputData.Vehicle.Components.AxleGearInputData;
-
+			if (axleGear == null)
+				return null;
+			
 			return new XElement(_vif + XMLNames.Component_Axlegear,
 				new XElement(_vif + XMLNames.ComponentDataWrapper,
 					new XAttribute(_xsi + "type", "vif:AxlegearDataVIFType"),

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFElectricEnergyStorageType.cs

@@ -19,7 +19,9 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var electricStorages = inputData.JobInputData.Vehicle.Components.ElectricStorage.ElectricStorageElements;
-			
+			if (electricStorages == null)
+				return null;
+
 			var result = new List<XElement>();
 			
 			foreach (var entry in electricStorages) {

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFEngineType.cs

@@ -21,6 +21,8 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var engine = inputData.JobInputData.Vehicle.Components.EngineInputData;
+			if (engine == null)	
+				return null;
 
 			return new XElement(_vif + XMLNames.Component_Engine,
 					new XElement(_vif + XMLNames.ComponentDataWrapper,

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFIepcType.cs

@@ -19,6 +19,8 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var iepc = inputData.JobInputData.Vehicle.Components.IEPC;
+			if (iepc == null)
+				return null;
 
 			return new XElement(_vif + XMLNames.Component_IEPC,
 					new XElement(_vif + XMLNames.ComponentDataWrapper,

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFTorqueConverterType.cs

@@ -20,6 +20,8 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var torque = inputData.JobInputData.Vehicle.Components.TorqueConverterInputData;
+			if (torque == null)
+				return null;
 			
 			return new XElement(_vif + XMLNames.Component_TorqueConverter,
 					new XElement(_vif + XMLNames.ComponentDataWrapper,

VectoCore/VectoCore/OutputData/XML/DeclarationReports/VehicleInformationFile/VehicleInformationFile_0_1/Components/VIFTransmissionType.cs

@@ -23,6 +23,8 @@ namespace TUGraz.VectoCore.OutputData.XML.DeclarationReports.VehicleInformationF
 		public XElement GetElement(IDeclarationInputDataProvider inputData)
 		{
 			var transmission = inputData.JobInputData.Vehicle.Components.GearboxInputData;
+			if (transmission == null)
+				return null;
 
 			return new XElement(_vif + XMLNames.Component_Transmission,
 					new XElement(_vif + XMLNames.ComponentDataWrapper,