您好,添加字段需要通过fieldInfos.Add()添加。可以参考以下代码:           
                FieldInfo fieldInfoNew = new FieldInfo();
                fieldInfoNew.Name = fieldName;
                fieldInfoNew.Type = FieldType.Text;
                fieldInfoNew.Caption = fieldName;
                fieldInfoNew.IsRequired = false;
                m_datasetVector.FieldInfos.Add(fieldInfoNew);//添加重叠字段
 希望可以帮助到您!