当具有列表验证的单元格被更新（用户从列表中选择其他值）时，另一个单元格将自动更新

Question

I have a cell that has a list validation that a user can select from a list of Names. When the user selects a Name (from list validation in "C7"), I want a cell right beneath it in "C9" to automatically call a function that I have written in a class module called CalculateGrade(). How can I trigger a cell value change event from a user selecting a different name from the list validation to execute the function CalculateGrade() in a different cell?

Answer 1

Your function isn't recalculating because it has no way of knowing that the cell that changed value (eg C7) will change its outcome. You should have written the function to have C7 passed into it as a parameter. Once this function has C7 as a precedent , any change in C7 will trigger a recalculation of the function.

You've decided to keep the code for the CalculateGrade() function a secret but it probably goes something like this:

function CalculateGrade()
    dim tmp as double, str as string

    str = range("C7").value
    'do something here to get a grade from the name in C7
    CalculateGrade = tmp

end function

This is how it should be written:

function CalculateGrade(rList as range)
    dim tmp as double, str as string

    str = rList.value
    'do something here to get a grade from the new name in C7 (aka rList)
    CalculateGrade = tmp

end function

This modified function is not called like =CalculateGrade() ; it is called like =CalculateGrade(C7) . With C7 as a precedent to the function, any change in C7 will recalculate the function and return a new value.

A UDF can take advantage of all the tools available to native worksheet functions The commands in the Formulas ► Formula Auditing group are powerful diagnostic tools but greatly underutilized. There is a good discussion on the auditing tools available in Find and correct errors in formulas . Determining precedents is in the Display the relationships between formulas and cells section.

There is an alternative using the Application.Volatile Method where the function will recalculate whenever anything in the workbook changes but passing in the cell containing the list validation as a precedent provides much more functionality and does not lock you down to a single cell to use for list validation like hard-coding the cell address does.