Insert error - Cannot insert explicit value for identity column in table 'YouTableName' when IDENTITY_INSERT is set to OFF.

Cannot insert explicit value for identity column in table ‘category’ when IDENTITY_INSERT is set to OFF.

 private static string BuildInsertQuery(IDbConnection connection, Type type)
        {
            string sql;
            if (!_insertQueryCache.TryGetValue(type, out sql))
            {
                var tableName = Resolvers.Table(type);
                var keyProperty = Resolvers.KeyProperty(type);
                var typeProperties = Resolvers.Properties(type)
                                              .Where(p => p != keyProperty || keyProperty.GetSetMethod() != null)
                                              .Where(p => p.GetSetMethod() != null)
                                              .ToArray();

                var columnNames = typeProperties.Select(Resolvers.Column).ToArray();
                var paramNames = typeProperties.Select(p => "@" + p.Name).ToArray();

                var builder = GetBuilder(connection);

                sql = builder.BuildInsert(tableName, columnNames, paramNames, keyProperty);

                _insertQueryCache[type] = sql;
            }

            return sql;
        }

I think this line of code is a bug:

 .Where(p => p != keyProperty || keyProperty.GetSetMethod() != null)

The old version works fine;

Resolvers.Properties(type).Where(p => p != keyProperty).ToList();  

[henkmollema]

It should work if you remove the setter (e.g. set;) in your POCO.

[henkmollema]

Dapper.FluentMap.Dommel now supports configuring the identity of a property.