查询动态参数。NotSupportedException

Question

我在使用Dapper查询参数时遇到了一些小问题。

我有：

• WebApi接收所有所需数据(实体名称、列、过滤器等)的请求。最深级别的过滤器具有这样的结构(此模型由ctor从api模型构建)：

    public class QueryFilterItem
    {
        public string Name { get; }
        public string FieldName { get; }
        public object Value { get; }
        public ComparisonType ComparisonType { get; }
    }

• 查询执行器，它处理api调用

var arguments = new ExpandoObject();
// ...
arguments.TryAdd($"{filter.Name}Entity{filter.FieldName}", filter.Value);
// ... This part above is a part of another helper class, which is dynamically building filter query data

IEnumerable<dynamic> result;

using (var connection = DbConnectionFactory.CreateDbConnection())
{
    result = connection.Query(sqlQuery, arguments); // tried with wrapping into DynamicParameters
}

从这个代码中，我得到了一个例外：

System.NotSupportedException: The member MyFilterItemEntityId 
of type System.Text.Json.JsonElement cannot be used as a parameter value
   at Dapper.SqlMapper.LookupDbType(Type type, String name, Boolean demand, ITypeHandler& handler) in /_/Dapper/SqlMapper.cs:line 418
   at Dapper.DynamicParameters.AddParameters(IDbCommand command, Identity identity) in /_/Dapper/DynamicParameters.cs:line 232
   at Dapper.DynamicParameters.Dapper.SqlMapper.IDynamicParameters.AddParameters(IDbCommand command, Identity identity) in /_/Dapper/DynamicParameters.cs:line 151
   at Dapper.SqlMapper.<>c__DisplayClass165_0.<GetCacheInfo>b__0(IDbCommand cmd, Object obj) in /_/Dapper/SqlMapper.cs:line 1714
   at Dapper.CommandDefinition.SetupCommand(IDbConnection cnn, Action`2 paramReader) in /_/Dapper/CommandDefinition.cs:line 129
   at Dapper.SqlMapper.<QueryImpl>d__140`1.MoveNext() in /_/Dapper/SqlMapper.cs:line 1080
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Dapper.SqlMapper.Query[T](IDbConnection cnn, String sql, Object param, IDbTransaction transaction, Boolean buffered, Nullable`1 commandTimeout, Nullable`1 commandType) in /_/Dapper/SqlMapper.cs:line 725
   at Dapper.SqlMapper.Query(IDbConnection cnn, String sql, Object param, IDbTransaction transaction, Boolean buffered, Nullable`1 commandTimeout, Nullable`1 commandType) in /_/Dapper/SqlMapper.cs:line 652
   at DappertStorageTest.Cqrs.SelectQueryHandler.GetByFilters(SelectQuery query)
   at DappertStorageTest.Cqrs.SelectQueryHandler.Handle(SelectQuery query)
   at System.Dynamic.UpdateDelegates.UpdateAndExecute2[T0,T1,TRet](CallSite site, T0 arg0, T1 arg1)
   at MAS.DappertStorageTest.Cqrs.Infrastructure.QueryProcessor.Execute[TResult](IQuery`1 query)
   at MAS.DapperStorageTest.Controllers.DataController.Select(SelectRequest selectRequest)
   at Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<<InvokeActionMethodAsync>g__Logged|12_1>d.MoveNext()

参数值(不是异常的一部分)：

sqlQuery:使用DapperStorageTest；从乘客位置选择* (Id = @MyFilterItemEntityId)

参数：{MyFilterItemEntityId，ValueKind = String："7d570abd-576d-425f-9d24-d84314d299ba"} (raw)

有人能帮我吗？

Answer 1

由于xanatos异常导致了web模型的映射。根据api模型，过滤器值具有object类型，asp.net核心将字符串映射为JsonElement。从object切换到string类型。

public class QueryFilterItem
    {
        public string Name { get; }
        public string FieldName { get; }
        public object Value { get; } // Here
        public ComparisonType ComparisonType { get; }
    }