解决导入时间不填写时转换报错的问题

be/Modules/Shared/src/Win_in.Sfs.Shared.Application/ExportAndImport/ClosedXmlExportImportService.cs

@@ -187,8 +187,11 @@ public class ClosedXmlExportImportService : IExportImportService
                         }
                         else
                         {
-                            var propertyValue = Convert.ChangeType(value.ToString(), propertyType);
+                            if (value.ToString() != "")
-                            property.SetValue(model, propertyValue);
+                            {
+                                var propertyValue = Convert.ChangeType(value.ToString(), propertyType);
+                                property.SetValue(model, propertyValue);
+                            }
                         }
                     }
                 }