unoplatform/uno · error · Exception

Invalid identifier character {Current}

Error message

Invalid identifier character {Current}

What it means

Thrown by ParseXBindIdentifier when the very first character of an expected identifier is not a valid identifier character (letter, digit, or underscore). The parser calls TryEatValidIdentifier, which returns false if no letter/digit/underscore was consumed at all.

Source

Thrown at src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/Utils/XBindExpressionParser.CoreParser.cs:231

					path = new XBindIndexerAccess() { Path = path, Index = _xBind.Substring(currentPosition, _position - currentPosition) };
					_position++;
				}
				else
				{
					break;
				}
			}

			return path;
		}

		private XBindIdentifier ParseXBindIdentifier()
		{
			var identifierStart = _position;
			if (!TryEatValidIdentifier())
			{
				throw new Exception($"Invalid identifier character {Current}");
			}

			if (Current == ':' && LookAhead == ':')
			{
				_position += 2;

				if (!TryEatValidIdentifier())
				{
					throw new Exception($"Invalid identifier character {Current}");
				}
			}

			return new XBindIdentifier() { IdentifierText = _xBind.Substring(identifierStart, _position - identifierStart) };
		}

		private bool TryEatValidIdentifier()
		{
			var foundValid = false;

View on GitHub (pinned to 0418340488)

Solutions

1. Inspect the x:Bind path at the reported position and replace the invalid character with a valid identifier.
2. If you intended an operator or expression, rewrite the binding using a function or a property that returns the computed value.
3. Remove any stray non-identifier characters from the path.

Example fix

<!-- before -->
<Text Text="{x:Bind @Name}" />
<!-- after -->
<Text Text="{x:Bind Name}" />

// Validate x:Bind path identifiers start with a letter, digit, or underscore:
// Linting check: identifier boundaries in x:Bind should not start with symbols like @, +, -, etc.

When it happens

Trigger: An x:Bind path contains a character that starts an identifier but is invalid — e.g. a symbol like '+', '-', '@', or a parenthesis/dot in a position where the parser expects an identifier name.

Common situations: Expression-style x:Bind that the parser does not support (e.g. arithmetic operators); a malformed path after a '.' or at the start of the binding; stray markup characters copied into the binding string.

Related errors

• Missing parenthesis?
• Expected attached property path to be member access.
• Expected ')' in attached property syntax.
• x:Bind indexing expects a single literal argument
• Only properties and fields can be indexed.

AI-assisted analysis of unoplatform/uno@0418340488 (2026-08-13). Data as JSON: /api/errors/aa767f41c22256a8. Report an issue: GitHub.