dotnet/wpf · error

SR.IntegerCollectionLengthLessThanZero

Error message

SR.IntegerCollectionLengthLessThanZero

What it means

During binary XAML deserialization (BAML) of an IntegerCollection, DeserializeFrom reads an Int32 length prefix from the stream. If the length is negative the serialized data is corrupt or was produced by an incompatible writer, so ArgumentException(SR.IntegerCollectionLengthLessThanZero) is thrown before allocating the Int32Collection.

Solutions

1. Rebuild the application so BAML resources are regenerated from valid XAML source.
2. Verify the binary stream being passed to ConvertCustomBinaryToObject is intact and originates from a matching WPF compiler version.
3. Regenerate the resource containing the Int32Collection (e.g. recompile the .xaml into the assembly).

Example fix

// before: deserializing a possibly corrupted stream
var obj = XamlInt32CollectionSerializer.StaticConvertCustomBinaryToObject(syncVersion, suspectBytes);
// after: guard length prefix first
if (BitConverter.ToInt32(suspectBytes, 0) < 0) throw new InvalidDataException("Corrupt IntegerCollection binary data");
var obj = XamlInt32CollectionSerializer.StaticConvertCustomBinaryToObject(syncVersion, suspectBytes);

if (data == null || data.Length < 4 || BitConverter.ToInt32(data, 0) < 0)
    throw new InvalidDataException("IntegerCollection binary payload has invalid length prefix");

try { obj = serializer.ConvertCustomBinaryToObject(data); }
catch (ArgumentException ex) when (ex.Message.Contains("less than zero")) { /* treat as corrupt payload */ }

When it happens

Trigger: Calling ConvertCustomBinaryToObject or StaticConvertCustomBinaryToObject on a BAML stream whose IntegerCollection record begins with a negative Int32 count (e.g. truncated, corrupted, or hand-crafted binary data).

Common situations: Corrupted or truncated compiled BAML resources in an assembly, binary data edited or generated by third-party tooling, or version mismatches where the binary XAML format changed between WPF builds.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• SR.UnknownIndexType
• Unrecognized float type in BAML file.
• ArgumentOutOfRangeException (timeout was Duration.Automatic)
• Can't Assign to Known Type attributes
• Collection_BadRank

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/773d0d68338b8128. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Markup/XamlInt32CollectionSerializer.cs:275

            BinaryReader reader)
        {
            return DeserializeFrom( reader ); 
        }          


        private static Int32Collection DeserializeFrom( BinaryReader reader )
        {
            Int32Collection theCollection; 
            IntegerCollectionType type; 

            type = (IntegerCollectionType) reader.ReadByte(); 

            int count = reader.ReadInt32(); 


            if ( count < 0 ) 
            {
                throw new ArgumentException(SR.IntegerCollectionLengthLessThanZero); 
            }                
                    
            theCollection = new Int32Collection( count ); 
                                
            if ( type == IntegerCollectionType.Consecutive ) 
            {
                // Get the first integer 
                int first = reader.ReadInt32(); 

                for( int i = 0; i < count; i ++)
                {
                    theCollection.Add( first + i ); 
                }
            }
            else
            {
                switch( type ) 
                {

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