Textchanged event for combobox not firing if values are changed using arrow keys

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Hi,
I am working on a VB.Net Windows Forms application. I added a ComboBox to my form, set its "DropDownStyle" proprty to DropDownList and added a few items in it. Now, when I am running the application and changing the combo box value with the mouse, everything is working fine and TextChanged event is firing. But if I am changing its values using up/down arrow keys, the TextChanged event is not firing.

Can anybody explain why?

Regards,
Shishir Wahi

What I have tried:

If I change the "DropDownStyle" proprty to DropDown then the issue is gone, but I have to use DropDownList style only.

Posted 21-May-23 0:07am

shishirwahi

Updated 21-May-23 0:47am

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OriginalGriff 21-May-23 6:56am

Solution updated.

1 solution

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OriginalGriff · Answer 1 · 2023-05-21T00:47:00

Solution 1

Because the change doesn't happen until the drop down element closes - which indicates that the user is happy with his selection, just as a click with the mouse does.

At that point, you get the event - but not before.

You do however get the SelectedIndexChanged even while the arrow keys are being pressed.

Posted 21-May-23 0:47am

OriginalGriff

Updated 21-May-23 0:56am

v2

Comments

shishirwahi 21-May-23 7:01am

That's the issue. The event isn't firing even after the ComboBox loses focus. The "SelectedValueChanged" event is raised, "SelectedIndexChanged" is getting raised but NOT "TextChanged".

OriginalGriff 21-May-23 7:16am

See the revised solution.

shishirwahi 21-May-23 7:28am

Yes, I already mentioned in my comment that the SelectedIndexChanged event is getting raised, but the "Text" property is bound to a field of my database table and if the TextChanged event is not raised, the underlying dataset will not get updated. So, can you please suggest any other property that can be used for data binding instead of "Text"?

OriginalGriff 21-May-23 7:43am

There isn't one - it's by design, as the user in in control of what happens, and his decision isn't "final" until the dropdown portion of the control closes.
And it's probably a bad idea to update databases directly while the user is making his mind up and trying to find the option he wants. That normally happens when the user is ready and signals so by making a positive action like clicking the "Save" or "OK" button. That way, they can "undo" the changes by cancelling the update.

shishirwahi 21-May-23 7:52am

No, the database is not getting updated on textchanged event, just the dataset. There is a "Save" and "Revert" button on the form that the user presses to save or cancel the updates.

OriginalGriff 21-May-23 8:12am

So why are you updating the dataset if the user hasn't finished?

Ralf Meier 21-May-23 16:25pm

If xou really want this you can set the Text-Property to the SelectedIndex when the SelectedIndexChanged is firing. But I wouldn't do so because normally you don't have a Selection if you are only scrolling through the items of the ComboBox ...