ASP.NET Core升级后表单字典模型绑定异常适配方案咨询

一段业务代码在ASP.NET MVC 5环境中可稳定运行，升级至ASP.NET Core后出现功能异常，提交的表单数据格式如下图所示：

接口端点定义 #

ASP.NET Core中的接口端点代码如下：

public IActionResult GetExpressionEditor([FromForm]GetExpressionEditorWidgetModel model)

模型类定义 #

接口绑定使用的C#模型类代码如下：

public class GetExpressionEditorWidgetModel
{
    public string Name { get; set; }
    public ExpressionEditorViewModel ExpressionEditorData { get; set; }
}

public class ExpressionEditorViewModel
{
    public string Expression { get; set; }

    public IDictionary<string, ExpressionEditorAttribute> SymbolToAttributeMap
    {
        get
        {
            if (this._symbolToAttributeMap == null)
            {
                return new Dictionary<string, ExpressionEditorAttribute>();
            }
            
            return this._symbolToAttributeMap.ToDictionary(entry => entry.Key, entry => ExpressionEditorAttribute.SetDefaults(entry.Key, entry.Value));
        }

        // 默认setter
        set { this._symbolToAttributeMap = value; }
    }

    public Dictionary<string, string> Data { get; set; }

    private IDictionary<string, ExpressionEditorAttribute> _symbolToAttributeMap;
}

模型绑定过程中抛出如下异常：

System.ArgumentNullException
错误信息：Value cannot be null. Parameter name: key

at System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector)
at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.CollectionModelBinder`1.<BindModelAsync>d__14.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.DictionaryModelBinder`2.d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.ComplexTypeModelBinder.d__10.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.ComplexTypeModelBinder.d__10.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.d__11.MoveNext()

经数小时调试、跟踪模型绑定内部执行逻辑，确认ASP.NET Core默认不支持expressionEditorData.data.index这种.key后缀的Data字典表单语法，仅支持如下索引式字典提交语法：

expressionEditorData.data[0].Key = "index"    
expressionEditorData.data[0].Value = 0 

待咨询的问题如下：

• 是否有内置配置可实现.key = value格式的字典绑定？
• 是否有其他可直接使用的内置模型绑定器？
• 若要保留原有提交格式的绑定能力，是否只能通过自定义模型绑定实现？

内容的提问来源于stack exchange，提问作者badazzhindu