kendo telerik 中导入 RTF 文件格式的问题

Question

我正在尝试在kendo中上传rtf文件，但它抛出以下错误，

   at System.ThrowHelper.ThrowKeyNotFoundException()
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.Elements.Lists.HtmlExportListManager.ShouldRestartLevel(List list, Int32 listLevelIndex)
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.HtmlContentManager.<ExportParagraph>d__1f.MoveNext()
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.HtmlContentManager.<ExportBlockContainer>d__b.MoveNext()
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.Elements.BodyElement.<OnEnumerateInnerElements>d__0.MoveNext()
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.Elements.HtmlElementBase.WriteContent(IHtmlWriter writer, IHtmlExportContext context)
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.Elements.HtmlElementBase.Write(IHtmlWriter writer, IHtmlExportContext context)
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.Elements.HtmlElementBase.WriteContent(IHtmlWriter writer, IHtmlExportContext context)
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Model.Elements.HtmlElementBase.Write(IHtmlWriter writer, IHtmlExportContext context)
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.Export.HtmlExporter.Export(IHtmlWriter writer, IHtmlExportContext context)
   at Telerik.Windows.Documents.Flow.FormatProviders.Html.HtmlFormatProvider.ExportOverride(RadFlowDocument document, Stream output)
   at Telerik.Windows.Documents.Common.FormatProviders.TextBasedFormatProviderBase`1.Export(T document)
   at Unite.Infrastructure.SQL.Repositories.ConsentRepository.GetHtmlFromDocument(RadFlowDocument document) in D:\WorkSpace\Unite2.0\Dev Branch\Unite\Unite.Infrastructure.SQL\Repositories\ConsentRepository.cs:line 337

我需要上传rtf文件