Error CS0854 when you’re using Moq with optional parameters

Problem Optional parameters aren’t optional when you’re using Moq. When you’re setting up or verifying a method call on a mock object, and the method has an optional parameter that you didn’t specify a value for, you’ll get the following compiler error: Error CS0854 – An expression tree may not contain a call or invocation … Read more

C# – IDE0060: Remove unused parameter

If you have a method with a parameter, and that parameter is not used in the method, then you’ll get the IDE0060 message telling you to remove the unused parameter. Here’s an example of code that would trigger this message: The encrypt parameter isn’t being used in the Send() method, triggering the IDE0060 message: IDE0060 … Read more

TargetParameterCountException: Parameter count mismatch

When you are using reflection to call a method, you may run into this exception: System.Reflection.TargetParameterCountException: Parameter count mismatch. This exception is straightforward – you aren’t passing in the correct number of parameters to MethodInfo.Invoke(). This article shows three different cases where you might run into this exception when using reflection. Using reflection to invoke … Read more