aspnetboilerplate/aspnetboilerplate · error · KeyNotFoundException

The property was not found in entity

Error message

The property {propertyInfo.Name} was not found in {mainMap.EntityType.Name} entity

What it means

GetPropertyMap throws KeyNotFoundException when the supplied MemberInfo is not among the properties mapped on the main entity's ClassMapper. It is used while resolving left/right property maps for reference (join) mappings, so a property that participates in a reference but isn't mapped on the entity triggers this.

Solutions

1. Add the missing property to the entity's ClassMapper (ensure it is mapped, not Ignored)
2. Verify the MemberInfo/name used in the reference configuration belongs to mainMap.EntityType
3. Check auto-mapping conventions (accessibility, get/set) so the property is discovered
4. Rebuild mappings if a cached map predates an entity change

Example fix

// before
Map(x => x.CustomerId).Ignore(); // not mapped
// reference config references x => x.CustomerId -> throws
// after
Map(x => x.CustomerId); // mapped, resolvable in reference config

bool mapped = mainMap.Properties.Any(p => p.MemberInfo == propertyInfo);
if (!mapped) throw new InvalidOperationException($"{propertyInfo.Name} is not mapped on {mainMap.EntityType.Name}");

bool IsMappedOn(IClassMapper map, MemberInfo mi) => map?.Properties?.Any(p => p.MemberInfo == mi) == true;

try { BuildReferenceSql(...); } catch (KeyNotFoundException ex) when (ex.Message.Contains("was not found in")) { throw new MappingException("Reference configuration points to an unmapped property", ex); }

When it happens

Trigger: Building a reference mapping where the referenced property name/MemberInfo belongs to a different entity, or the property is not registered in the ClassMapper (e.g. it's Ignore()d or auto-mapping skipped it).

Common situations: Typo or renamed property in a reference configuration; property excluded by MapConvention (private, no setter) but still referenced in a join config; mapping definitions stale after entity refactoring.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

• was not found for
• Map was not found for
• No columns were mapped.
• Table column not set.
• TriggerIdentity generator cannot be used with multi-column…

AI-assisted analysis of aspnetboilerplate/aspnetboilerplate@2323c13a15 (2026-09-08). Data as JSON: /api/errors/e878bbb171ab7d20. Report an issue: GitHub.

Appendix: source

Thrown at src/Abp.Dapper/Dapper-Extensions/Sql/SqlGenerator.cs:331

        var sql = new StringBuilder($"DELETE FROM {GetTableName(classMap)}");
        sql.Append(" WHERE ").Append(predicate.GetSql(this, parameters, true));
        return sql.ToString();
    }

    public virtual string IdentitySql(IClassMapper classMap)
    {
        return Configuration.Dialect.GetIdentitySql(GetTableName(classMap));
    }

    public virtual string GetReferenceKey(IMemberMap map)
    {
        return $"{map.ClassMapper.TableName}.{map.ColumnName}";
    }

    private static IMemberMap GetPropertyMap(IClassMapper mainMap, MemberInfo propertyInfo)
    {
        if (!mainMap.Properties.Any(p => p.MemberInfo == propertyInfo))
            throw new KeyNotFoundException($"The property {propertyInfo.Name} was not found in {mainMap.EntityType.Name} entity");
        return mainMap
            .Properties
            .Where(p => p.MemberInfo == propertyInfo)
            .Select(propertyMap => propertyMap)
            .Single();
    }

    private string GetJointTables(IClassMapper mainMap, Table table, IDictionary<string, object> parameters, IList<IReferenceMap> includedProperties = null)
    {
        if (parameters == null)
        {
            throw new ArgumentNullException(nameof(parameters), $"{nameof(parameters)} cannot be null.");
        }

        var result = new StringBuilder();
        var joins = new StringBuilder();
        var sql = new StringBuilder();
        var parent = Tables.Single(t => t.Identity == table.ParentIdentity);

View on GitHub (pinned to 2323c13a15)