Legible or not: C# multiple ternary operators + Throw if unmatched [closed]

Question

Do you find the following C# code legible?

private bool CanExecuteAdd(string parameter) {     return         this.Script == null ? false         : parameter == "Step" ? true         : parameter == "Element" ? this.ElementSelectedInLibrary != null && this.SelectedStep != null         : parameter == "Choice" ? this.SelectedElement != null         : parameter == "Jump" ? this.SelectedStep != null         : parameter == "Conditional jump" ? false         : false.Throw("Unknown Add parameter {0} in XAML.".F(parameter)); } 

where Throw is defined as:

public static T Throw<T>(this T ignored, string message) {     throw new Exception(message); } 

I know that's not idiomatic C#. However, would you be able at understand it at first or second glance? Or did I stray too far?

Answer 1

Why not use a switch? I think it's way more readable.

private bool CanExecuteAdd(string parameter) {     if (Script == null)         return false;      switch (parameter) {         case "Step":             return true;         case "Element":             return ElementSelectedInLibrary != null && SelectedStep != null;         case "Choice":             return SelectedElement != null;         case "Jump":             return SelectedStep != null;         case "Conditional jump":             return false;         default:             throw new Exception(string.Format("Unknown Add parameter {0} in XAML.", parameter));     } } 

Answer 2

I've used this sort of code in Java a fair amount. I don't like the false.Throw bit, but having multiple conditionals like this (particularly formatted this way) is fine in my view.

It's slightly strange the very first time you see it, but after that it's just a handy pattern to know about.

One alternative to using false.Throw here would be something like this:

bool? ret = this.Script == null ? false     : parameter == "Step" ? true     : parameter == "Element" ? this.ElementSelectedInLibrary != null && this.SelectedStep != null     : parameter == "Choice" ? this.SelectedElement != null     : parameter == "Jump" ? this.SelectedStep != null     : parameter == "Conditional jump" ? false     : null;  if (ret == null) {     throw new ArgumentException(        string.Format("Unknown Add parameter {0} in XAML.", parameter); } return ret.Value; 

EDIT: Actually, in this case I wouldn't use either if/else or this pattern... I'd use switch/case. This can be very compact if you want:

if (this.Script == null) {     return false; } switch (parameter) {     case "Step": return true;     case "Element": return this.ElementSelectedInLibrary != null && this.SelectedStep != null;     case "Choice": return this.SelectedElement != null;     case "Jump": return this.SelectedStep != null;     default: throw new ArgumentException(         string.Format("Unknown Add parameter {0} in XAML.", parameter); }