abpframework/abp · error · ArgumentException

{parameterName} has a default value!

Error message

{parameterName} has a default value!

What it means

Thrown by Check.NotDefaultOrNull<T> when the nullable struct is non-null but its value equals default(T) (e.g. Guid.Empty, 0, DateTime.MinValue). It is the second guard in that method and exists because default values of structs are often semantically 'unset'. ArgumentException carries parameterName.

Source

Thrown at framework/src/Volo.Abp.Core/Volo/Abp/Check.cs:355

            throw new ArgumentException($"{parameterName} is out of range min: {minimumValue} - max: {maximumValue}");
        }

        return value;
    }

    public static T NotDefaultOrNull<T>(
        [System.Diagnostics.CodeAnalysis.NotNull] T? value,
        [InvokerParameterName][NotNull] string parameterName)
        where T : struct
    {
        if (value == null)
        {
            throw new ArgumentException($"{parameterName} is null!", parameterName);
        }

        if (value.Value.Equals(default(T)))
        {
            throw new ArgumentException($"{parameterName} has a default value!", parameterName);
        }

        return value.Value;
    }
}

View on GitHub (pinned to 7ed43b1931)

Solutions

1. Generate a real value (Guid.NewGuid()) or fetch the real id before calling NotDefaultOrNull.
2. If default(T) is a legal value for your domain, use Check.NotNull on a boxed reference or a different guard instead.
3. Set sensible non-default initializers on DTO properties (e.g. CreatedAt = Clock.Now).
4. Reject default(T) at the API boundary so the caller is told the field is effectively unset.

Example fix

// before
var id = Check.NotDefaultOrNull(entity.Id, nameof(entity.Id));

// after
entity.Id = entity.Id == Guid.Empty ? Guid.NewGuid() : entity.Id;
var id = Check.NotDefaultOrNull(entity.Id, nameof(entity.Id));

static bool IsNotDefault<T>(T? value) where T : struct
    => value is not null && !value.Value.Equals(default(T));

if (!IsNotDefault(entity.Id)) return BadRequest("Id is empty/default");

static bool IsMeaningful(Guid? id) => id is Guid g && g != Guid.Empty;

try
{
    var id = Check.NotDefaultOrNull(entity.Id, nameof(entity.Id));
}
catch (ArgumentException ex) when (ex.ParamName == nameof(entity.Id))
{
    return BadRequest(ex.Message);
}

When it happens

Trigger: Calling Check.NotDefaultOrNull(value, nameof(value)) where value is Guid.Empty, 0, DateTime.MinValue, default(int), etc.

Common situations: A Guid id left as Guid.Empty by deserialization, a date defaulting to 0001-01-01, or an enum/int that was never assigned and read as 0.

Related errors

• {parameterName} is null!
• Given type ({item.AssemblyQualifiedName}) should be instance
• repositoryNameWithOrganization '{repositoryNameWithOrganizat
• Can not set {companyName} if {companyNamePlaceHolder} is nul
• len argument can not be bigger than given string's length!

AI-assisted analysis of abpframework/abp@7ed43b1931 (2026-08-13). Data as JSON: /api/errors/6af452b85f10e0ce. Report an issue: GitHub.