Joining Data

Question

In "Joining Data" in the help, the following code is given:

// Build a memory relationship class.
Type memRelClassFactoryType = Type.GetTypeFromProgID(
    "esriGeodatabase.MemoryRelationshipClassFactory");
IMemoryRelationshipClassFactory memRelClassFactory = 
    (IMemoryRelationshipClassFactory)Activator.CreateInstance(memRelClassFactoryType)
    ;
IRelationshipClass relationshipClass = memRelClassFactory.Open("ParcelsOwners",
    parcelsFeatureClass, "PARCEL_ID", (IObjectClass)ownersTable, "PARCEL_ID", 
    "Is Owned By", "Owns", esriRelCardinality.esriRelCardinalityOneToOne);

But no explanation is provided for "ownersTable."  What is it?

I have created a QueryClass that implements the ITable interface and can be successfully casted to an ITable but that ITable cannot be casted to IObjectClass.  What can be?

GregRieck · Answer

In "Joining Data" in the help, the following code is given:

// Build a memory relationship class.
Type memRelClassFactoryType = Type.GetTypeFromProgID(
    "esriGeodatabase.MemoryRelationshipClassFactory");
IMemoryRelationshipClassFactory memRelClassFactory = 
    (IMemoryRelationshipClassFactory)Activator.CreateInstance(memRelClassFactoryType)
    ;
IRelationshipClass relationshipClass = memRelClassFactory.Open("ParcelsOwners",
    parcelsFeatureClass, "PARCEL_ID", (IObjectClass)ownersTable, "PARCEL_ID", 
    "Is Owned By", "Owns", esriRelCardinality.esriRelCardinalityOneToOne);

But no explanation is provided for "ownersTable."  What is it?

I have created a QueryClass that implements the ITable interface and can be successfully casted to an ITable but that ITable cannot be casted to IObjectClass.  What can be?

Try casting parcelsFeatureClass as an IObjectClass like you did the ownerstable. It's expecting an IObjectClass.
Basically the IRelationshipClass portion of the code is examining your relationship class. If you open your relationship class in Arc Catalog and examine the properties you should be able to use the .Net IntelliSense to correctly complete the required parameters of the function.

G

GeorgeFaraj · Answer

I believe it is the ITable to join to the IFeatureLayer.  You need to replace OwnersTable with the Table in your implementation you wish to join to the target layer.  What is the source table and FeatureLayer you want to join?

In case anyone needs to know: I can only pass an actual ITable.  If you build your own class that implements ITable it will not pass correctly.

JamesCrandall · Answer

In the ESRI example they pass "OwnersTable" - what is that?

I believe it is the ITable to join to the IFeatureLayer.  You need to replace OwnersTable with the Table in your implementation you wish to join to the target layer.  What is the source table and FeatureLayer you want to join?