microsoft/aspire · error · ArgumentNullException

Object value cannot be null (ArgumentNullException: parent)

Error message

Object value cannot be null (ArgumentNullException: parent)

What it means

The AzureConnectorNamespaceConnectionResource constructor requires a non-null parent Connector Namespace resource; the parent's Name is used to build the connection's Bicep identifier. Passing null parent throws ArgumentNullException.

Solutions

1. Use the AddConnection extension on the Connector Namespace resource builder, which supplies the parent automatically
2. Build the namespace with AddAzureConnectorNamespace before creating connections
3. Fix factory/DI code so the parent resource is resolved before connection creation

Example fix

// before
var conn = new AzureConnectorNamespaceConnectionResource(name, connectionName, displayName, null!, connectorName);
// after
nsBuilder.AddConnection(name, connectorName, options => options.ConnectionName = connectionName);

if (parent is null) throw new InvalidOperationException("Connector Namespace parent must be built before creating connections.");

bool canCreate = parent is not null;

try { new AzureConnectorNamespaceConnectionResource(...); } catch (ArgumentNullException ex) when (ex.ParamName == "parent") { /* use AddConnection instead */ }

When it happens

Trigger: Constructing AzureConnectorNamespaceConnectionResource directly with parent = null, e.g. calling AddConnection with a builder whose Resource is null or building the connection before the namespace resource exists.

Common situations: Manual provisioning-model construction bypassing AddConnection; dependency-injection or factory code that resolves the parent lazily and yields null; copy-pasted resource constructors where the parent argument was dropped.

Related errors

• Object value cannot be null (ArgumentNullException: parent)
• Value cannot be null. (Parameter 'config')
• Value cannot be null. (Parameter 'parent')
• Value cannot be null. (Parameter 'parent')
• Value cannot be null. (Parameter 'parent')

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/d36462c6bcab06ad. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.Azure.ConnectorNamespace/AzureConnectorNamespaceConnectionResource.cs:35

{
    /// <summary>
    /// Initializes a new instance of the <see cref="AzureConnectorNamespaceConnectionResource"/> class.
    /// </summary>
    /// <param name="name">The Aspire resource name.</param>
    /// <param name="connectionName">The Azure connector connection name.</param>
    /// <param name="connectorName">The connector catalog name.</param>
    /// <param name="displayName">The friendly display name shown for the connection.</param>
    /// <param name="parent">The parent connector namespace resource.</param>
    public AzureConnectorNamespaceConnectionResource(string name, string connectionName, string connectorName, string? displayName, AzureConnectorNamespaceResource parent)
        : base(name)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(connectionName);
        ArgumentException.ThrowIfNullOrWhiteSpace(connectorName);

        ConnectionName = connectionName;
        ConnectorName = connectorName;
        DisplayName = displayName;
        Parent = parent ?? throw new ArgumentNullException(nameof(parent));
        BicepIdentifier = ConnectorNamespaceBicepIdentifiers.CreateConnection(parent.Name, name);
    }

    /// <summary>
    /// Gets the Azure connector connection name.
    /// </summary>
    public string ConnectionName { get; }

    /// <summary>
    /// Gets the connector catalog name.
    /// </summary>
    public string ConnectorName { get; }

    /// <summary>
    /// Gets the friendly display name shown for the connection.
    /// </summary>
    public string? DisplayName { get; }

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