What causes "{parameterName} can not be null, empty or white space!" in abpframework/abp?

Pass a non-empty, non-whitespace string.

abpframework/abp · error · ArgumentException

{parameterName} can not be null, empty or white space!

Error message

{parameterName} can not be null, empty or white space!

What it means

Check.NotNullOrWhiteSpace(string) rejects null, empty, or all-whitespace strings using IsNullOrWhiteSpace(), so whitespace-only values also fail (stricter than NotNullOrEmpty). After the whitespace check it applies optional maxLength/minLength bounds. Use this when the string must carry meaningful content, not just be present.

Source

Thrown at framework/src/Volo.Abp.Core/Volo/Abp/Check.cs:72

        if (minLength > 0 && value.Length < minLength)
        {
            throw new ArgumentException($"{parameterName} length must be equal to or bigger than {minLength}!", parameterName);
        }

        return value;
    }

    [ContractAnnotation("value:null => halt")]
    public static string NotNullOrWhiteSpace(
        [System.Diagnostics.CodeAnalysis.NotNull] string? value,
        [InvokerParameterName][NotNull] string parameterName,
        int maxLength = int.MaxValue,
        int minLength = 0)
    {
        if (value.IsNullOrWhiteSpace())
        {
            throw new ArgumentException($"{parameterName} can not be null, empty or white space!", parameterName);
        }

        if (value!.Length > maxLength)
        {
            throw new ArgumentException($"{parameterName} length must be equal to or lower than {maxLength}!", parameterName);
        }

        if (minLength > 0 && value!.Length < minLength)
        {
            throw new ArgumentException($"{parameterName} length must be equal to or bigger than {minLength}!", parameterName);
        }

        return value;
    }

    [ContractAnnotation("value:null => halt")]
    public static string NotNullOrEmpty(
        [System.Diagnostics.CodeAnalysis.NotNull] string? value,

View on GitHub (pinned to 7ed43b1931)

Solutions

Pass a non-empty, non-whitespace string.
If blank is a valid 'unset' state, default-fall to a meaningful value at the caller before calling.
Trim input upstream and validate before forwarding into the guarded API.

Example fix

// before
Check.NotNullOrWhiteSpace(raw, nameof(raw)); // throws on blank

// after
Check.NotNullOrWhiteSpace(string.IsNullOrWhiteSpace(raw) ? "default" : raw, nameof(raw));

Defensive patterns

Strategy: validation

Validate before calling

if (string.IsNullOrWhiteSpace(value))
    value = fallback;
Check.NotNullOrWhiteSpace(value, nameof(value));

Type guard

bool IsMeaningful(string? s) => !string.IsNullOrWhiteSpace(s);

Prevention

Trim and default-fall blank input at the caller before guarded APIs.
Prefer Check.NotNullOrWhiteSpace over NotNullOrEmpty when blank must fail.
Use [Required] on DTO properties so model binding rejects whitespace before your code runs.

When it happens

Trigger: Check.NotNullOrWhiteSpace(" ", nameof(x)), or an empty string, or null; an ABP API that requires a non-blank value receiving whitespace.

Common situations: Configuration keys that must have a value; display names; identifiers that cannot be whitespace; trimmed user input that ended up blank.

Related errors

AI-assisted analysis of abpframework/abp@7ed43b1931 (2026-08-13). Data as JSON: /api/errors/4b5bccee4e18c8de. Report an issue: GitHub.