builtbybel/FlyOOBE · error · ArgumentNullException

null

Error message

null

What it means

The ToolHubItemControl constructor requires a ToolHubDefinition describing which tool to render; it stores it and uses it in InitializeBasics/InitializeOptions/InitializeTextInput. A null definition is rejected immediately with ArgumentNullException because the control cannot initialize without tool metadata.

Solutions

1. Pass a valid ToolHubDefinition instance; verify the lookup/creation returned non-null before constructing the control
2. Skip null entries when building the tool list (e.g. `where tool != null`)
3. Fix the deserialization/loading code that produced a null ToolHubDefinition
4. Fail earlier with a clearer error at the catalog-load step if a required definition is missing

Example fix

// before
var control = new ToolHubItemControl(definitions.FirstOrDefault(d => d.Id == toolId)); // may be null
// after
var definition = definitions.FirstOrDefault(d => d.Id == toolId);
if (definition == null)
    throw new InvalidOperationException($"Tool definition '{toolId}' not found");
var control = new ToolHubItemControl(definition);

if (tool == null)
    throw new InvalidOperationException("ToolHubDefinition is required to create a ToolHubItemControl");
var control = new ToolHubItemControl(tool);

bool TryGetToolDefinition(string id, out ToolHubDefinition definition)
{
    definition = definitions.FirstOrDefault(d => d != null && d.Id == id);
    return definition != null;
}

try
{
    var control = new ToolHubItemControl(tool);
    flowLayoutPanel.Controls.Add(control);
}
catch (ArgumentNullException ex) when (ex.ParamName == "tool")
{
    SkipToolCard(toolId, "missing definition");
}

When it happens

Trigger: Calling `new ToolHubItemControl(null)` — e.g. a ToolHubDefinition lookup by id returned null, a list contained null entries, deserialization of the tool catalog produced nulls, or the definition list was built conditionally and the entry was skipped.

Common situations: Populating the ToolHub from a JSON/config catalog where a tool definition failed to deserialize; iterating over a definitions collection containing null placeholders; filtering the catalog removed a definition while UI code still references it by index or id.

Related errors

• null
• LoggerControlView cannot be null.

AI-assisted analysis of builtbybel/FlyOOBE@ed093a784d (2026-09-14). Data as JSON: /api/errors/311e54306dc81eee. Report an issue: GitHub.

Appendix: source

Thrown at Flyoobe/ToolHubView/ToolHubItemControl.cs:19

using System;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Flyoobe.ToolHub
{
    public partial class ToolHubItemControl : UserControl
    {
        private readonly ToolHubDefinition _tool;
        private readonly string _placeholderText = "Enter input (e.g., IDs or raw arguments)";

        public ToolHubItemControl(ToolHubDefinition tool)
        {
            InitializeComponent();
            _tool = tool ?? throw new ArgumentNullException(nameof(tool));

            InitializeBasics();
            InitializeOptions();
            InitializeTextInput();
            InitializePoweredByLink();
        }

        /// <summary>
        /// Basic label and layout setup
        /// </summary>
        private void InitializeBasics()
        {
            labelTitle.Text = _tool.Title;
            labelDescription.Text = _tool.Description;
            labelIcon.Text = _tool.Icon;
            progressBar.Visible = false;
            labelStatus.Text = string.Empty;
        }

View on GitHub (pinned to ed093a784d)