Question

I’m trying to use the ternary to return differing types, although I seem to be encountering some problems. My question is can the ternary operator not return differing types?

// This line causes an error
propertyGrid.Instance = (directoryRecord.directoryInfo != null) 
    ? directoryRecord.directoryInfo 
    : directoryRecord.fileInfo;

// Compiles fine
propertyGrid.Instance = directoryRecord.directoryInfo;

// Compiles fine
propertyGrid.Instance = directoryRecord.fileInfo;

Error

Type of conditional expression cannot be determined because there is
no implicit conversion between ‘System.IO.DirectoryInfo’ and
‘System.IO.FileInfo’

Answer 1

No, this doesn’t work like that.
The expression of a conditional operator has a specific type. Both types used in the expression must be of the same type or implicitly convertible to each other.

You can make it work like this:

propertyGrid.Instance = (directoryRecord.directoryInfo != null) 
    ? (object)directoryRecord.directoryInfo 
    : (object)directoryRecord.fileInfo;