Trapping ComboBox changes...

Dave Wilcox

On a comboBox change, I am trying to capture the old value and compare to the new value. If the user accidentally clicks the dropdown and simply selects the same value (thinking they are not changing anything) it will still trigger a change event and drive some code. If the user choose the same value, I want to trap for that and STOP the normal course of events.

I have tried SelectedValueChanged, SelectedIndexChanged, and Validating. Validating seems to only apply when the form closes.

Theoretically, I want to capture "TextOld" and compare to "TextNew" and see if they are the same. If they are then STOP.

2 Replies

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Bhuvanesh Mohankumar10y ago
Accepted answer
I suggest you to try this logic with Javscript
Let complete this validation in client side itself.
Check this sample codefor reference.
var oldSelValue = document.getElementById('CountryDropDown');
on Change event write the below code.
var tempSelValue = document.getElementById('CountryDropDown');
var newSelValue = document.getElementById('CountryDropDown');
If no change in old and new value [Use prevent deafult action for element in javascript]
if the user selected different value, then assign tempSelValue to oldSelValue
and again make thenewSelValue to tempSelValue
Mark as answer, if helpful.
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Dave Wilcox10y ago
I am doing this in C#, but I understand the concept and I can make it work. Thanks Bhuvanesh.
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