Question

This is a .NET error:

Error Message: String was not recognized as a valid Boolean.
Error Source : mscorlib

This may be a bit cryptic-sounding but that’s all I have to show. How to go about retracing what happened… I really need help on this, how can this come up if it didn’t appear before, though the application was the same.
thanks

Answer 1

This error occurs when using bool.Parse() and the input into the method is not convertible to a boolean value of true/false.

For instance:

string testBool = "true";
bool validBool = bool.Parse(testBool);
// this passes fine

testBool = "asdf";
validBool = bool.Parse(testBool);
// Exception: String was not recognized as a valid Boolean.

If you’re using .NET 4.0 or higher, you can use bool.TryParse() instead; it will not throw the exception if it receives invalid input. Otherwise, wrap the statement in a try / catch to consume it.