Conditional data validation

Hi All,

I am one of a group of volunteers who look after a village hall. We have a basic accounts sheet with a column for income and another for expense. We also have a column for 'category'.

The category is to help us group certain types of incomes and expenditures - examples of incomes might be Donations, Bookings, Events (actually precious few!). Details of categories of expense would include Licenses, Utilities, Maintenance, Cleaning etc ... a lot more expenses than incomes!

I have data validation set up so that all items can be given a category and the categories then display the sum of all appropriate values - so I can see at a glance how much is spend on cleaning etc.

The Category column contains the validation and is key to me being able to summarise annual accounts. Currently the data validation list is separate and contains both incomes and expenses. What I'd like is to delete the data validation master list and to use the two summary lists instead. The Category colum would have data validation that depends on whether there was an amount on the 'Income' column or in the 'Expense' column.

SO ... in excel english what I'd like is to set up data validation that says:
If there is no amount in either the income or expense cell for this row error "please enter an income or expense amount first"
if the cell in the income cell for this row has a value then use the validation list "incomelist"
If the cell in the expense cell for this row has a value then use the validation list "expenselist"

I've been having a bit of a look around and found the 'indirect' function that I don't fully understand but I continue to work on that.

https://www.excelforum.com/attachmen...1&d=1617027462

Hoping this wont be too complex but I can't seem to get it at the moment.