[SOLVED] [QComboBox and Model/View] Associate PK and data in ComboBox
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[quote author="loladiro" date="1309266013"]
You can always do what Volker suggested above (That accesses another column with the current index). If you think that's too much code everytime you want to access the index, I'm afraid you'll have to subclass QComboBox
[/quote]That would just move that code into the subclass...
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Thanks, Volker. Now, that brings another question. I'm using something like that to fetch data from a DB.
!https://lh6.googleusercontent.com/-Eyg_apku1S8/TgnRSDAAVnI/AAAAAAAAB34/YKLXdQehE84/s800/Screenshot-Contr%25C3%25B4les%2520de%2520qualit%25C3%25A9-1.jpg!The Category CC changes according to the Index of the GroupCC, as said earlier. Now, since I cannot set the Index of the ComboBox, the complexity of the query seems to increase rapidly (I need to account for the index of the group when binding a value to the category, etc...)
By subclassing QComboBox, could I set the index myself, or is this really impossible? Thanks!
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You get a signal when the group combo box changes. Get the data out of the group combo box' model (you have at least two choices pointed out here in the thread) and fill the model for the category's model accordingly. You'll have to re-select from the SQL anyways or put all the data in cache or the like which you access with the selected group's data.
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Oh, the category CC already changes according to the index of the group CC (see the code I first posted).
However, the five ComboBox uniquely identifies a set of data in the DB. Hence, I thought that if I could change the index of the ComboBox that I could directly use
@query.prepare("...WHERE IndexAcc = :acc");
query.bindValue(":acc", accComboBox->currentIndex();@because I thought that using something like
@
query.prepare("...WHERE name_acc = :acc");
query.bindValue(":acc", accComboBox->currentText().toString());@was error-prone. Ain't it?
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[quote author="loladiro" date="1309266013"]
You can always do what Volker suggested above (That accesses another column with the current index). If you think that's too much code everytime you want to access the index, I'm afraid you'll have to subclass QComboBox
[/quote]Okay, now I understand this part better. However, what I need is relational table, because for one value of the GroupComboBox index, I have several possible values for the Category ComboBox index.
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A primary key is a primary key - a string value need not be unique.
So you're doing it the wrong way anyways.
query.bindValue() sets the value to the current value of that variable. It is not updated once the value changes! No matter how often you run the query, it always yields the same results!
You must call bindValue again after the value has changed (i.e. after the combo box has a new current item) and re-run the query!
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[quote author="Volker" date="1309267439"]A primary key is a primary key - a string value need not be unique.
So you're doing it the wrong way anyways.
query.bindValue() sets the value to the current value of that variable. It is not updated once the value changes! No matter how often you run the query, it always yields the same results!
You must call bindValue again after the value has changed (i.e. after the combo box has a new current item) and re-run the query![/quote]
Yes, I know all that. This sort of query will be connected to a button (now yet implemented) that will bind the values of whatever is in the ComboBoxes to a prepared SQL query and update the UI accordingly. However, from what you're telling me, I can access the PK associated with a certain item in the groupComboBox by using the currentIndex() of the groupComboBox and externally mapping it to its PK. That's fine.
However, for each item in the groupComboBox, there are several items in the categoryComboBox. Now, since each time I change the index of groupComboBox, the contents of the categoryComboBox are changed, I cannot map the PK of the categoryComboBox to its index. Do you understand my problem?
Because of this one-to-many relationship, it is somewhat difficult to implement something that would bind the right value in the SQL query. Now, and I want this to be the final question in this grudgingly long thread, can I set the indices of ComboBoxes if I subclass them?
(To me, it seems like the most robust solution to fetch data from the DB.)
Thanks, y'all!
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Okay. I'll work a little bit more on this and come back later.
Thanks for your tips!
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It was easier that I thought. I wanted to filter data according to a foreign key. I had to fetch the PK of a table according to the value of the ComboBox.
Here's how I did it:
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catModel->setFilter(""CAT_IndexGroupe" = " % QString::number(
groupModel->data(groupModel->index(ui->MW_groupComboBox->currentIndex(), groupModel->fieldIndex("IndexGroupe")), Qt::DisplayRole).toInt()));@Thanks everyone for your tips!