elsa-workflows/elsa-core · error · ArgumentException

Invalid value type.

Error message

Invalid value type.

What it means

Thrown by the private ConvertAnyDateType helper in ObjectConverter when the supplied value is neither a DateTime nor a DateTimeOffset. It is a generic guard: any other runtime type passed through ConvertTo to a date target type fires this exception, so callers must ensure the source value is one of the two supported date kinds before conversion.

Solutions

1. Pass DateTime or DateTimeOffset values to date-typed conversions
2. Parse strings with DateTime.Parse/DateTimeOffset.Parse before calling ConvertTo
3. Catch ArgumentException and handle the fallback

Example fix

// before
var d = ObjectConverter.ConvertTo<DateTime>("2024-01-01");
// after
var d = DateTime.Parse("2024-01-01", CultureInfo.InvariantCulture);

if (value is not (DateTime or DateTimeOffset))
    value = DateTime.Parse(value.ToString()!, CultureInfo.InvariantCulture);

static bool IsDateValue(object? v) => v is DateTime or DateTimeOffset;

try { d = ObjectConverter.ConvertTo<DateTime>(v); } catch (ArgumentException) { d = DateTime.MinValue; }

When it happens

Trigger: ConvertTo<DateTime> with a value like a string or long that survived earlier conversion steps and reached the date branch unconverted.

Common situations: Workflow inputs carrying date-as-string into a DateTime-typed property after ChangeType did not handle it; deserialized JsonElement values.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Invalid target type.
• A conversation ID is required. (Parameter 'conversation')
• A conversation user ID is required. (Parameter…
• Cannot deserialize to .
• Failed to deserialize

AI-assisted analysis of elsa-workflows/elsa-core@fe9217bdfa (2026-09-13). Data as JSON: /api/errors/e218e44b04fd6b7c. Report an issue: GitHub.

Appendix: source

Thrown at src/clients/Elsa.Api.Client/Extensions/ObjectConverter.cs:218

        return dateTypes.Contains(type);
    }

    /// <summary>
    /// Converts any date type to the specified target type.
    /// </summary>
    /// <param name="value">Any of <see cref="DateTime"/> or <see cref="DateTimeOffset"/>.</param>
    /// <param name="targetType">Any of <see cref="DateTime"/> or <see cref="DateTimeOffset"/>.</param>
    /// <returns>The converted value.</returns>
    /// <exception cref="ArgumentException">Thrown if <paramref name="value"/> is not of type <see cref="DateTime"/> or <see cref="DateTimeOffset"/>.</exception>
    private static object ConvertAnyDateType(object value, Type targetType)
    {
        return targetType switch
        {
            { } t when t == typeof(DateTime) => value switch
            {
                DateTime dateTime => dateTime,
                DateTimeOffset dateTimeOffset => dateTimeOffset.DateTime,
                _ => throw new ArgumentException("Invalid value type.")
            },
            { } t when t == typeof(DateTimeOffset) => value switch
            {
                DateTime dateTime => new DateTimeOffset(dateTime),
                DateTimeOffset dateTimeOffset => dateTimeOffset,
                _ => throw new ArgumentException("Invalid value type.")
            },
            _ => throw new ArgumentException("Invalid target type.")
        };
    }
}

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