abpframework/abp · error · FormatException

Incorrect syntax at char {i}! These is no opening brackets f

Error message

Incorrect syntax at char {i}! These is no opening brackets for the closing bracket }.

What it means

While tokenizing a format string, a '}' is read when inDynamicValue is false (no preceding '{' opened a dynamic segment). The tokenizer treats '}' exclusively as the close of a dynamic value, so a stray closing brace with no matching open is a syntax error and throws FormatException. Used internally by FormattedStringValueExtracter.Extract/IsMatch.

Source

Thrown at framework/src/Volo.Abp.Core/Volo/Abp/Text/Formatting/FormatStringTokenizer.cs:39

                case '{':
                    if (inDynamicValue)
                    {
                        throw new FormatException("Incorrect syntax at char " + i + "! format string can not contain nested dynamic value expression!");
                    }

                    inDynamicValue = true;

                    if (currentText.Length > 0)
                    {
                        tokens.Add(new FormatStringToken(currentText.ToString(), FormatStringTokenType.ConstantText));
                        currentText.Clear();
                    }

                    break;
                case '}':
                    if (!inDynamicValue)
                    {
                        throw new FormatException("Incorrect syntax at char " + i + "! These is no opening brackets for the closing bracket }.");
                    }

                    inDynamicValue = false;

                    if (currentText.Length <= 0)
                    {
                        throw new FormatException("Incorrect syntax at char " + i + "! Brackets does not containt any chars.");
                    }

                    var dynamicValue = currentText.ToString();
                    if (includeBracketsForDynamicValues)
                    {
                        dynamicValue = "{" + dynamicValue + "}";
                    }

                    tokens.Add(new FormatStringToken(dynamicValue, FormatStringTokenType.DynamicValue));
                    currentText.Clear();

View on GitHub (pinned to 7ed43b1931)

Solutions

Remove the stray '}' or pair it with a matching '{...}' dynamic segment.
Add a brace-balance validation pass over the format before calling Extract and reject/sanitize unbalanced templates.
Catch FormatException around Extract when the format is user-supplied and treat it as a non-match.

Example fix

// before: stray closing brace, no opening brace
var r = FormattedStringValueExtracter.Extract(input, "user} profile");
// throws FormatException: no opening bracket for the closing }

// after: drop the brace, or open a proper dynamic segment
var r = FormattedStringValueExtracter.Extract(input, "user profile");
// or: var r = FormattedStringValueExtracter.Extract(input, "{name} profile");

Defensive patterns

Strategy: try-catch

Validate before calling

static bool HasBalancedBraces(string format)
{
    if (format.IsNullOrEmpty()) return true;
    var depth = 0;
    foreach (var c in format)
    {
        if (c == '{') depth++;
        else if (c == '}')
        {
            if (depth == 0) return false; // stray closing brace
            depth--;
        }
    }
    return depth == 0;
}

if (!HasBalancedBraces(format)) { /* reject template */ }

Try / catch

try
{
    result = FormattedStringValueExtracter.Extract(str, format);
}
catch (FormatException)
{
    result = new ExtractionResult(false); // treat malformed format as non-match
}

Prevention

Run a brace-balance check on every template when it is loaded from config.
Never build formats by naive concatenation of fragments that may each contain braces.
Unit-test format templates with sample inputs before shipping.
Keep format strings in constants so typos surface at compile/review time.

When it happens

Trigger: Calling FormattedStringValueExtracter.Extract(str, format) with a format whose first brace character is '}': "} text", "a}b", or "name}suffix". Any '}' encountered before any '{' triggers it (test case at FormattedStringTokenizer_Test.cs:15 tokenizes "} wrong format").

Common situations: Config or template strings with an unbalanced closing brace (typo, truncated copy-paste); JSON/code-snippet templates pasted as formats where '}' survived from an object literal; format strings built by concatenation that dropped the opening '{'.

Related errors

AI-assisted analysis of abpframework/abp@7ed43b1931 (2026-08-13). Data as JSON: /api/errors/5b41a8368d7327a3. Report an issue: GitHub.