public MemoryConnectionProperties()

public Geodatabase GetMemoryGeodatabase()
{
    // Creates the default memory geodatabase if not exist or connects to an existing one if already exists
    Geodatabase memoryGeodatabase = new Geodatabase(new MemoryConnectionProperties());

    // Creates schema
    SchemaBuilder schemaBuilder = new SchemaBuilder(memoryGeodatabase);
    schemaBuilder.Create(new TableDescription("MyTable", new List<FieldDescription>()));
    schemaBuilder.Build();

    return memoryGeodatabase;
}