Storing information from a Combobox in layer in QGIS/PyQt

Question

I am building a plugin for QGIS and want to add a string to a created polygon. In my dialog I was able to create a ComboBox filled with 10 different strings which can be added while creating the polygon. But when I identify this object this information doesn't seem to be stored. Is there a way to connect this information to the layer? Here is what I created until now:

Objects = ['Trees on grass', 'Trees on avenue', 'Grass field', 'Green roofs', 'Cool roofs', 'Facade greening', 'Solar Panels', 'Pond/river', 'Fountain', 'Surface albedo change']

#insert this string in Combobox
self.ObjectType = QComboBox()
object = self.ObjectType.insertItems(0, Objects)

# Add this object feature to layer
for layer in QgsProject.instance().mapLayers().values():
   if 'field=' + self.tr('Drawings') + ':string(255,0)' in layer.dataProvider().dataSourceUri()[-28:]:  # must have its first field named Drawings, string type
     self.layers.append(layer)
     self.layerBox.addItem(layer.object)

Does anyone have a clue to enhance the last part?