dotnet runtime_exception ai_generated true

System.ArgumentNullException: Value cannot be null. (Parameter 'paramName')

ID: dotnet/argumentexception

Also available as: JSON · Markdown
93%Fix Rate
94%Confidence
85Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
8 active — — —

Root Cause

ArgumentException and ArgumentNullException are thrown when a method receives an invalid or null argument. Typically caused by missing DI registrations, incorrect configuration, or caller bugs. Fix by validating inputs and ensuring proper service registration.

generic

Workarounds

  1. 93% success Trace the null or invalid argument back to its source and fix the caller 
    Read the exception message for the parameter name, then trace the call stack to find where the invalid value originates. Fix the upstream code that produces the null or invalid value, or add proper DI registration if the argument comes from dependency injection
  2. 90% success Register missing services in the DI container 
    If the ArgumentNullException occurs in a constructor injected by DI, check Program.cs or Startup.cs for missing service registrations. Add builder.Services.AddScoped<IMyService, MyService>() or equivalent registration

Dead Ends

Common approaches that don't work:

  1. Passing empty strings or placeholder values to bypass argument validation 80% fail

    The method expects meaningful values; passing empty or dummy values causes logic errors or silent data corruption downstream

  2. Removing argument validation from the method to suppress the exception 90% fail

    Removes a safety net that prevents invalid data from entering the system; the invalid argument will cause harder-to-debug errors deeper in the call stack

Error Chain

Leads to:
Preceded by:
Frequently confused with: