# System.Text.Json.JsonException: The JSON value could not be converted to System.String. Path: $.propertyName | LineNumber: 1 | BytePositionInLine: 20.

- **ID:** `dotnet/serialization-json-ignore-attribute`
- **Domain:** dotnet
- **Category:** type_error
- **Verification:** ai_generated
- **Fix Rate:** 90%

## Root Cause

System.Text.Json deserialization fails because a JSON property has an unexpected type (e.g., number instead of string) or is missing, often due to mismatched model attributes like JsonIgnore.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| System.Text.Json 6.0.x | active | — | — |
| System.Text.Json 7.0.x | active | — | — |
| System.Text.Json 8.0.x | active | — | — |

## Workarounds

1. **Add a custom JsonConverter to handle type conversion, e.g., convert number to string.** (85% success)
   ```
   Add a custom JsonConverter to handle type conversion, e.g., convert number to string.
   ```
2. **Use JsonSerializerOptions.Converters to register converter globally.** (90% success)
   ```
   Use JsonSerializerOptions.Converters to register converter globally.
   ```
3. **Change the C# model property type to object or JsonElement and handle casting manually.** (70% success)
   ```
   Change the C# model property type to object or JsonElement and handle casting manually.
   ```

## Dead Ends

- **** — Adding JsonSerializerOptions.IgnoreNullValues doesn't fix type mismatches. (95% fail)
- **** — Changing the JSON source to match the C# model is often not feasible in production. (80% fail)
- **** — Using JsonSerializerOptions.PropertyNameCaseInsensitive only helps with casing, not types. (90% fail)