stride3d/stride · error · ArgumentException

Inconsistent number of parameters: expected 1, 2 or 4…

Error message

Inconsistent number of parameters: expected 1, 2 or 4 values, got {values.Length}.

What it means

ThicknessMultiConverter.Convert builds a Thickness from an array of binding values and accepts exactly 1 (uniform), 2 (horizontal/vertical), or 4 (left/top/right/bottom) values. It throws this ArgumentException from Convert (ThicknessMultiConverter.cs:36) in the switch's default branch when values.Length is anything else (0, 3, 5+).

Solutions

Adjust the MultiBinding so it contains exactly 1, 2, or 4 child bindings.
If you have 3 values, add the missing one or supply a uniform value so the count is 4 (or 2/1 as appropriate).
If the count is legitimately variable, extend or wrap the converter to handle other arities.
Validate bindings.Length before assigning the converter in code.

Example fix

// before
<multi:Binding .../> <!-- 3 bindings: left, top, right -->
// after (add the missing bottom binding)
<multi:Binding .../> <!-- 4 bindings: left, top, right, bottom -->

Defensive patterns

Strategy: validation

Validate before calling

bool ok = values is not null && (values.Length == 1 || values.Length == 2 || values.Length == 4);

Type guard

static bool HasValidArity(object[] v) => v is { Length: 1 or 2 or 4 };

Try / catch

try { return converter.Convert(values, typeof(Thickness), param, culture); }
catch (ArgumentException) { return new Thickness(0); }

Prevention

Count MultiBinding children whenever you add or remove a binding in XAML.
Remember the supported arities: 1 (uniform), 2 (horizontal/vertical), 4 (l/t/r/b).
Build complex MultiBindings in code where counts are checked at compile/author time.

When it happens

Trigger: A MultiBinding with 0, 3, or more than 4 child bindings feeding this converter — e.g. three separate left/top/right bindings, or an empty bindings list.

Common situations: Adding/removing a binding in XAML without updating the count expected by the converter; forgetting to bind the fourth side; building the MultiBinding programmatically and miscounting.

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

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/a8a749309e9c158e. Report an issue: GitHub.

Appendix: source

Thrown at sources/presentation/Stride.Core.Presentation.Wpf/ValueConverters/ThicknessMultiConverter.cs:36

            {
                case 1:
                    var uniform = ConverterHelper.ConvertToDouble(values[0], culture);
                    return new Thickness(uniform);

                case 2:
                    var horizontal = ConverterHelper.ConvertToDouble(values[0], culture);
                    var vertical = ConverterHelper.ConvertToDouble(values[1], culture);
                    return new Thickness(horizontal, vertical, horizontal, vertical);

                case 4:
                    var left = ConverterHelper.ConvertToDouble(values[0], culture);
                    var top = ConverterHelper.ConvertToDouble(values[1], culture);
                    var right = ConverterHelper.ConvertToDouble(values[2], culture);
                    var bottom = ConverterHelper.ConvertToDouble(values[3], culture);
                    return new Thickness(left, top, right, bottom);

                default:
                    throw new ArgumentException($"Inconsistent number of parameters: expected 1, 2 or 4 values, got {values.Length}.", nameof(values));
            }
        }
    }
}

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