///<summary>Creates a spatial query which performs a spatial search for features in the supplied feature class and has the option to also apply an attribute query via a where clause.</summary>
///  
///<param name="featureClass">An ESRI.ArcGIS.Geodatabase.IFeatureClass</param>
///<param name="searchGeometry">An ESRI.ArcGIS.Geometry.IGeometry (Only high-level geometries can be used)</param>
///<param name="spatialRelation">An ESRI.ArcGIS.Geodatabase.esriSpatialRelEnum (e.g., esriSpatialRelIntersects)</param>
///<param name="whereClause">A System.String, (e.g., "city_name = ‘Redlands‘").</param>
///   
///<returns>An IFeatureCursor holding the results of the query will be returned.</returns>
///   
///<remarks>Call the SpatialQuery method by passing in a reference to the Feature Class, a Geometry used for the search and the spatial operation to be preformed. An exmaple of a spatial opertaion would be intersects (e.g., esriSpatialRelEnum.esriSpatialRelContains). If you would like to return everything found by the spatial operation use "" for the where clause. Optionally a whereclause (e.g. "income > 1000") maybe applied if desired. The SQL syntax used to specify the where clause is the same as that of the underlying database holding the data.</remarks>
public ESRI.ArcGIS.Geodatabase.IFeatureCursor PerformSpatialQuery(ESRI.ArcGIS.Geodatabase.IFeatureClass featureClass, ESRI.ArcGIS.Geometry.IGeometry searchGeometry, ESRI.ArcGIS.Geodatabase.esriSpatialRelEnum spatialRelation, System.String whereClause)
{
  // create a spatial query filter
  ESRI.ArcGIS.Geodatabase.ISpatialFilter spatialFilter = new ESRI.ArcGIS.Geodatabase.SpatialFilterClass();

  // specify the geometry to query with
  spatialFilter.Geometry = searchGeometry;

  // specify what the geometry field is called on the Feature Class that we will be querying against
  System.String nameOfShapeField = featureClass.ShapeFieldName;
  spatialFilter.GeometryField = nameOfShapeField;

  // specify the type of spatial operation to use
  spatialFilter.SpatialRel = spatialRelation;

  // create the where statement
  spatialFilter.WhereClause = whereClause;

  // perform the query and use a cursor to hold the results
  ESRI.ArcGIS.Geodatabase.IQueryFilter queryFilter = new ESRI.ArcGIS.Geodatabase.QueryFilterClass();
  queryFilter = (ESRI.ArcGIS.Geodatabase.IQueryFilter)spatialFilter;
  ESRI.ArcGIS.Geodatabase.IFeatureCursor featureCursor = featureClass.Search(queryFilter, false);

  return featureCursor;
}