iOfficeAI/OfficeCLI · error · ArgumentException

Unknown part type: {partType}. Supported: chart, chartex, dr

Error message

Unknown part type: {partType}. Supported: chart, chartex, drawing-group, ole

What it means

The switch over partType.ToLowerInvariant() in AddPart fell through to the default branch — the supplied part type is not one of the supported carriers: chart, chartex, drawing-group, ole. The message enumerates the valid values so the caller can correct the type.

Source

Thrown at src/officecli/Handlers/Excel/ExcelHandler.Add.cs:1364

                var oleWsElement = GetSheet(oleWs);
                var oleObjects = oleWsElement.GetFirstChild<OleObjects>();
                if (oleObjects == null)
                {
                    oleObjects = new OleObjects();
                    oleWsElement.AppendChild(oleObjects);
                }
                OpenXmlElement oleChild = oleObjectXml.Contains("AlternateContent", StringComparison.Ordinal)
                    ? new DocumentFormat.OpenXml.AlternateContent(oleObjectXml)
                    : new OleObject(oleObjectXml);
                oleObjects.AppendChild(oleChild);
                ReorderWorksheetChildren(oleWsElement);
                SaveWorksheet(oleWs);

                return (oleRid, $"/{oleSheetName}/ole");
            }

            default:
                throw new ArgumentException(
                    $"Unknown part type: {partType}. Supported: chart, chartex, drawing-group, ole");
        }
    }

    private static void RemapDrawingRelationshipId(
        OpenXmlElement root, string sourceId, string destinationId)
    {
        const string relNs =
            "http://schemas.openxmlformats.org/officeDocument/2006/relationships";
        foreach (var element in root.Descendants().Prepend(root))
        {
            foreach (var attr in element.GetAttributes()
                .Where(a => a.NamespaceUri == relNs && a.Value == sourceId)
                .ToList())
            {
                element.SetAttribute(new OpenXmlAttribute(
                    attr.Prefix, attr.LocalName, attr.NamespaceUri, destinationId));
            }

View on GitHub (pinned to 1ced45e900)

Solutions

1. Use one of: chart, chartex, drawing-group, ole.
2. For picture/shape/table/slicer/sparkline use the Add(...) element API, not AddPart.
3. Check the type spelling and casing (matching is case-insensitive but spelling must match).
4. Re-dump to see the exact partType labels the emitter uses.

Example fix

// before
handler.AddPart("/Sheet1", "smartart", props);
// after — chartEx is the xlsx extended-chart carrier
handler.AddPart("/Sheet1", "chartex", props);

var supported = new[]{ "chart", "chartex", "drawing-group", "ole" };
if (!supported.Contains(partType?.ToLowerInvariant()))
    throw new ArgumentOutOfRangeException(nameof(partType),
        $"'{partType}' is not a supported part type. Use one of: {string.Join(", ", supported)}");

static bool IsSupportedPartType(string? t) =>
    t?.ToLowerInvariant() is "chart" or "chartex" or "drawing-group" or "ole";

try { handler.AddPart(parent, partType, props); }
catch (ArgumentException ex) when (ex.Message.Contains("Unknown part type"))
{ /* switch to a supported carrier or to the Add element API */ }

When it happens

Trigger: AddPart(parent, partType, ...) with a partType that is null (NullReferenceException aside, ToLowerInvariant would throw first), misspelled, differently cased-but-still-unknown, or a type that belongs to a different format (e.g. 'slide', 'smartart').

Common situations: Typo in the type string; passing a semantic element type (e.g. 'picture','shape') to AddPart instead of the Add path; using a pptx-specific part type on an xlsx file; stale documentation naming a removed type.

Related errors

• drawing-group hyperlink entries require non-empty Id and Tar
• Property 'sqref' (or 'range'/'ref') is required for validati
• Sheet not found: {sheetName}
• Move not supported for: {elementRef}. Supported: row[N], col
• Swap requires element paths (e.g. /Sheet1/row[1])

AI-assisted analysis of iOfficeAI/OfficeCLI@1ced45e900 (2026-08-13). Data as JSON: /api/errors/b15ca6fdcb02dd39. Report an issue: GitHub.