Question:

Validating list columns with respect to other column

Grace: 5 days ago

I have a list with two columns

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In platform column, user should not be able to enter Cobra again for internal speaker, Title is Single line of text and Platform is Lookup.

Can we do it using column validation.

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Answer:
Levi: 5 days ago

Assuming you are using SP2013.

Your question is a bit confusing but I would go with using CSR. With CSR you basically have full control over your edit and new forms by using Javascript. You can implement your custom validation logic with it.

To get you started: https://code.msdn.microsoft.com/office/Client-side-rendering-JS-2ed3538a