dotnet/wpf · error · ArgumentException

SR.Format(SR.ArgumentPropertyMustNotBeNull, "uriRemote"…

Error message

SR.Format(SR.ArgumentPropertyMustNotBeNull, "uriRemote", "OriginalString")

What it means

GetRemoteStream validates that the Uri's OriginalString is not null before resolving a site-of-origin resource. A Uri can be constructed such that OriginalString is null (e.g. default(Uri) survived the null check via serialization or UriKind.RelativeOrRelative tricks), and WPF treats that as an invalid argument. This guards the subsequent resolution logic from a malformed Uri instance.

Solutions

Ensure the Uri is constructed via a normal Uri constructor with a non-null string before passing it
Check uriRemote?.OriginalString != null before calling GetRemoteStream
Re-create the Uri from its string form if it came from deserialization
If the value may be absent, skip the call or use a relative Uri with UriKind.Relative

Example fix

// before
Application.GetRemoteStream(maybeUri);
// after
if (maybeUri?.OriginalString != null)
    Application.GetRemoteStream(maybeUri);

Defensive patterns

Strategy: type-guard

Validate before calling

bool hasString(Uri u) => u?.OriginalString != null;

Type guard

bool HasOriginalString(Uri u) => u is Uri uri && uri.OriginalString is string s;

Try / catch

try { Application.GetRemoteStream(uri); } catch (ArgumentException ex) { /* rebuild uri from its string form */ }

Prevention

Construct Uris only via standard constructors
Re-create Uris after deserialization
Treat deserialized Uri instances as suspect

When it happens

Trigger: Calling Application.GetRemoteStream with a Uri instance whose OriginalString is null — typically a Uri built through unusual paths (deserialization, default struct) rather than a normal constructor, since the constructor normally throws on null input.

Common situations: Uris round-tripped through serialization/formatters that skipped validation; reflection-created Uri instances; defensive check rarely hit because ArgumentNullException fires first on true nulls.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/0bc9d06246ac0cdd. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Application.cs:640

        /// <summary>
        /// Get PackagePart for a uri, the uri maps to a file which comes from the place
        /// where the application was originally deployed.
        ///
        /// The accepted uri could be relative uri such as "foo.jpg"
        ///
        /// or  pack Uri, "pack://siteoforigin:,,,/foo.jpg"
        ///
        /// </summary>
        /// <param name="uriRemote">the uri maps to the resource</param>
        /// <returns>PackagePart or null</returns>
        public static StreamResourceInfo GetRemoteStream(Uri uriRemote)
        {
            SiteOfOriginPart sooPart = null;

            ArgumentNullException.ThrowIfNull(uriRemote);

            if (uriRemote.OriginalString == null)
                throw new ArgumentException(SR.Format(SR.ArgumentPropertyMustNotBeNull, "uriRemote", "OriginalString"));

            if (uriRemote.IsAbsoluteUri)
            {
                if (!BaseUriHelper.SiteOfOriginBaseUri.IsBaseOf(uriRemote))
                {
                    throw new ArgumentException(SR.NonPackSooAbsoluteUriNotAllowed);
                }
            }

            Uri resolvedUri = BindUriHelper.GetResolvedUri(BaseUriHelper.SiteOfOriginBaseUri, uriRemote);

            Uri packageUri = PackUriHelper.GetPackageUri(resolvedUri);
            Uri partUri = PackUriHelper.GetPartUri(resolvedUri);

            //
            // SiteOfOriginContainer must have been added into the package cache, the code should just
            // take use of that SiteOfOriginContainer instance, instead of creating a new instance here.
            //

View on GitHub (pinned to 81131a70a4)