Interval grouping by Nullable<DateTime> doesn't work properly about devextreme.aspnet.data

[roman-simionov]

@GikiDev, thank you for your reply. Now I see the issue appears when EF is used. We will fix it in the context of this issue

[AlekseyMartynov]

Hi @GiviKDev

Would you please check the fixed NuGet from https://ci.appveyor.com/project/dxrobot/devextreme-aspnet-data/build/244/artifacts ?

You will need the following binding redirect in web.config:

<dependentAssembly>
 <assemblyIdentity name="DevExtreme.AspNet.Data" publicKeyToken="982f5dab1439d0f7"/>
 <bindingRedirect oldVersion="0.0.0.0-99.0.0.0" newVersion="99.0.0.0"/>
</dependentAssembly>

P.S. How to install a Nuget Package .nupkg file locally

[AlekseyMartynov]

Test case (in the context of GroupHelperTests):

var data = new[] {
    new { d = new DateTime?(new DateTime(1996, 7, 4)) },
    new { d = new DateTime?() }
};

var groups = CreateHelper(data).Group(data, new[] {
    new GroupingInfo { Selector = "d", GroupInterval = "year", IsExpanded = false },
    new GroupingInfo { Selector = "d", GroupInterval = "month", IsExpanded = false },
    new GroupingInfo { Selector = "d", GroupInterval = "day", IsExpanded = false }
});

@vconst @Alyar666
What behavior we expect?
Should null values be ignored during the calculation of date group intervals?

[vconst]

The null values should not be ignored. The groups array should contains item with key value null. The grid ignores the items property in header filter when key is null.

[AlekseyMartynov]

Do I understand correctly: there must be 3 group levels with null keys?

[vconst]

Yes

[AlekseyMartynov]

Fix will be included in release 1.2.1

[GiviKDev]

Hello,

Header Filter not working with Nullable<DateTime> when RemoteOperations is set to true.

public static object Load<T>(IQueryable<T> source, DataSourceLoadOptionsBase options);
method throws an exception:

Value cannot be null.
Parameter name: constructor

Version 1.2.3

[AlekseyMartynov]

@roman-simionov PTAL

[roman-simionov]

Hello @GiviKDev,

My attempts to reproduce the issue with the sample project were unsuccessful. The header filter works correctly with Nullable<DateTime> and the enabled RemoteOperations options. Would you please update my sample to illustrate the issue.

[GiviKDev]

Hello @roman-simionov ,
I updated your sample project, where you can reproduce current bug.

T458279.zip

[GiviKDev]

Hello,

Thanks, it's working like a charm.