JosefNemec/Playnite · warning · NotSupportedException

Cannot convert {value} to AspectRatio.

Error message

Cannot convert {value} to AspectRatio.

What it means

Thrown by AspectRatioTypeConverter.ConvertFrom when the supplied value cannot be parsed into an AspectRatio. The converter accepts a 'W:H' or 'WxH' style string (regex groups) and falls back to a default for designer previews; any other shape/value reaches the throw as NotSupportedException.

Source

Thrown at source/Playnite/Common/Sizes.cs:34

        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            if (value is string ratio)
            {
                var regex = Regex.Match(ratio, @"(\d+):(\d+)");
                if (regex.Success)
                {
                    return new AspectRatio(
                        Convert.ToInt32(regex.Groups[1].Value),
                        Convert.ToInt32(regex.Groups[2].Value));
                }
                else
                {
                    // For cases where this is called from designer element preview via binding expression
                    return new AspectRatio();
                }
            }

            throw new NotSupportedException($"Cannot convert {value} to AspectRatio.");
        }

        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            return sourceType == typeof(string);
        }
    }

    [TypeConverter(typeof(AspectRatioTypeConverter))]
    public class AspectRatio : IEquatable<AspectRatio>
    {
        public int Width { get; set; }
        public int Height { get; set; }

        public AspectRatio()
        {
        }

View on GitHub (pinned to 5911f4e964)

Solutions

1. Provide the ratio in the supported 'W:H' format (e.g. '16:9', '4:3').
2. Validate the string against the converter's regex before binding.
3. Ensure the bound value is a string and not null or a numeric type.

Example fix

// before
var ar = (AspectRatio)new AspectRatioTypeConverter().ConvertFrom(input);

// after — validate the ratio string first
static bool TryRatio(string s, out int w, out int h)
{
    w = h = 0;
    var m = System.Text.RegularExpressions.Regex.Match(s ?? "", @"^(\d+)\s*[:xX]\s*(\d+)$");
    return m.Success && int.TryParse(m.Groups[1].Value, out w) && int.TryParse(m.Groups[2].Value, out h);
}
if (!TryRatio(input, out var w, out var h)) { ar = new AspectRatio(); }
else { ar = new AspectRatio(w, h); }

static bool TryParseRatio(string s, out int w, out int h)
{
    w = h = 0;
    var m = System.Text.RegularExpressions.Regex.Match(s ?? "", @"^(\d+)\s*[:xX]\s*(\d+)$");
    return m.Success && int.TryParse(m.Groups[1].Value, out w) && int.TryParse(m.Groups[2].Value, out h);
}

static bool IsValidRatioString(string s, out int w, out int h) => TryParseRatio(s, out w, out h);

try { return (AspectRatio)new AspectRatioTypeConverter().ConvertFrom(input); }
catch (NotSupportedException) { return new AspectRatio(); /* default */ }

When it happens

Trigger: Binding a non-string value, or a string that does not match the expected W:H regex (e.g. '16/9', '1.77', 'wide', empty, or a decimal ratio); passing a null outside the designer path.

Common situations: User/theme config with a malformed aspect ratio string; a plugin/theme binding the wrong type; localized config using a different separator; designer hitting the converter with an unexpected value.

Related errors

• Backup output path not specified!
• No URL was given.
• Source directory does not exist or could not be found: {sour
• The icon is corrupt. Couldn't read the header.
• Non empty process name must be specified.

AI-assisted analysis of JosefNemec/Playnite@5911f4e964 (2026-08-13). Data as JSON: /api/errors/ce62ff7b3baf403f. Report an issue: GitHub.