SampleApp has very worthwhile examples of sync and async BusinessRule to check for the presence of numeric digits in strings. Unfortunately any string with a more that one word will returrn positive, i.e., the rule is broken. Here is the code:
bool result = string.IsNullOrEmpty(ce.Name) ||
!(from c in ce.Name.ToCharArray()
It appears that char.IsLetter() considers a space a number. For example, Good Morning returns a broken rule. My C# book says char.IsLetter considers only A-Z and a-z as letters, so that will exclude commas, periods, semicolons, etc also from the "Letter" category. char.IsDigit (positive if 0-9) might be a better test.
Thanks, that's good to know. Of course the sample isn't intended to have a great rule for detecting numerics - just to show how to build sync/async rules :)
Fortunately I'm messing with that sample at the moment though (enhancing it for a talk I'm giving at the Visual Studio Live! conference), so I'll see about making this change.
It came about when I entered O'Donnel in the name box. With the old style rules, I wouldn't have given it a second thought. I was so impressed with the new rule system as I was trying to dissect it to see how it worked, and what exactly was causing the error. It was my own surprize in discovering that a space character is not considered a letter that I felt I should share it.
Of course the name of the rule is StringOnlyLetters, so technically char.IsLetter is not the "wrong" test in the rule.
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