Within a C# procedure I am able to successfully render discrete data values using:

    pValRen.AddValue("A11", fieldName, (ISymbol)pExpressWay);
    pValRen.AddValue("A15", fieldName, (ISymbol)pExpressWay);

where `pValRen` is a `UniqueValueRenderer()` object, and, the strings `"A11"` and `"A15"` refer to discrete data values.  But, I need to group `"A11"` and `"A15"` together with a single reference value as suggested in the [online help][1].

I have attempted to create a group using:

    pValRen.AddReferenceValue("A15", pValRen.ReferenceValue["A11"]); 

or

    pValRen.AddValue(pValRen.ReferenceValue["A11"], fieldName, (ISymbol)pExpressWay);

but, both of these approaches result in an error.  How does one construct and use a ReferenceValue for the UniqueValueRenderer?


  [1]: http://desktop.arcgis.com/en/arcobjects/latest/net/webframe.htm#iuniquevaluerenderer.htm