public static ITypeSymbol GetElementType(ITypeSymbol collectionType)
{
switch (collectionType)
{
case INamedTypeSymbol namedType:
if (namedType.IsGenericType == false)
{
if (namedType.BaseType == null)
{
var indexer = namedType.GetMembers(WellKnownMemberNames.Indexer).OfType <IPropertySymbol>().FirstOrDefault();
if (indexer != null)
{
return(indexer.Type);
}
throw new NotSupportedException("Cannot determine collection element type");
}
if (ObjectHelper.IsSystemObject(namedType.BaseType))
{
return(namedType.BaseType);
}
return(GetElementType(namedType.BaseType));
}
return(namedType.TypeArguments[0]);
case IArrayTypeSymbol arrayType:
return(arrayType.ElementType);
default:
throw new NotSupportedException("Unknown collection type");
}
}
private ITypeSymbol GetElementType(ITypeSymbol collectionType)
{
switch (collectionType)
{
case INamedTypeSymbol namedType:
if (namedType.IsGenericType == false)
{
if (ObjectHelper.IsSystemObject(namedType.BaseType))
{
return(namedType.BaseType);
}
return(GetElementType(namedType.BaseType));
}
return(namedType.TypeArguments[0]);
case IArrayTypeSymbol arrayType:
return(arrayType.ElementType);
default:
throw new NotSupportedException("Unknown collection type");
}
}
