Connecting the index of a combobox to a model
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Hi
I'm trying out the model/view pattern in Qt and while it worked wonders for listviews, I can't seem to get it to work quite as I want with comboboxes.
I set the combobox to use the model of a QStringListModel, which properly populated the combobox with values. But I want the selected option in the combobox to also be stored in the model, so that it can be changed from other parts of the gui/some internal functionality.
I could make my model register all comboboxes when they're constructed and then later on update them manually with the setCurrentIndex method, but this feels like breaking the model/view pattern and missing out on core part of the built-in functionality.
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Hi
I'm trying out the model/view pattern in Qt and while it worked wonders for listviews, I can't seem to get it to work quite as I want with comboboxes.
I set the combobox to use the model of a QStringListModel, which properly populated the combobox with values. But I want the selected option in the combobox to also be stored in the model, so that it can be changed from other parts of the gui/some internal functionality.
I could make my model register all comboboxes when they're constructed and then later on update them manually with the setCurrentIndex method, but this feels like breaking the model/view pattern and missing out on core part of the built-in functionality.
@Mikkel said in Connecting the index of a combobox to a model:
I could make my model register all comboboxes when they're constructed and then later on update them manually with the setCurrentIndex method, but this feels like breaking the model/view pattern and missing out on core part of the built-in functionality.
You can subclass QStringListModel and add this information there.
This is not breaking model/view pattern - by default the model does not know anything about any view(s), so it also can't know which index is selected. But if you need this information - sure you can add it to the model, it's not forbidden ;-)
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@Mikkel said in Connecting the index of a combobox to a model:
I could make my model register all comboboxes when they're constructed and then later on update them manually with the setCurrentIndex method, but this feels like breaking the model/view pattern and missing out on core part of the built-in functionality.
You can subclass QStringListModel and add this information there.
This is not breaking model/view pattern - by default the model does not know anything about any view(s), so it also can't know which index is selected. But if you need this information - sure you can add it to the model, it's not forbidden ;-)
@sierdzio
Thank you for the response.
So i set up a custom model and overload the data/rowCount methods.
Would I then need to set up a delegate to make the indexChanged edit the value in my model and vice versa make my model set the index in the combobox? -
@sierdzio
Thank you for the response.
So i set up a custom model and overload the data/rowCount methods.
Would I then need to set up a delegate to make the indexChanged edit the value in my model and vice versa make my model set the index in the combobox?@Mikkel said in Connecting the index of a combobox to a model:
@sierdzio
Thank you for the response.
So i set up a custom model and overload the data/rowCount methods.
Would I then need to set up a delegate to make the indexChanged edit the value in my model and vice versa make my model set the index in the combobox?Depends on how you want to do it, I don't have a "best practice" recommendation here.
Either allow current index to be modified in
setData()and read bydata(), or make the index a property of the model and set it more automatically through your combobox (when current index is changed - set the property. When combo box is instantiated - read the property; etc.).
