/// <summary>
 /// The get sdmx structure type.
 /// </summary>
 /// <param name="xref">
 /// The xref. 
 /// </param>
 /// <returns>
 /// The <see cref="SdmxStructureType"/> . 
 /// </returns>
 public static SdmxStructureType GetSdmxStructureType(MaintainableReferenceBaseType xref)
 {
     return GetSdmxStructureType(xref.GetTypedRef<MaintainableRefBaseType>().@class);
 }
 /// <summary>
 /// The add ref.
 /// </summary>
 /// <param name="refType">
 /// The ref type. 
 /// </param>
 private void AddRef(MaintainableReferenceBaseType refType)
 {
     ICrossReference crossRef = RefUtil.CreateReference(this, refType);
     this.targetStructure = crossRef.TargetReference;
     this.structureReferences.Add(crossRef);
 }