Keep selected rows(ie checked rows) between pagination changed in HxGrid?

[chobo2]

Hi

I have an HX grid with pagination in it. I am loading the data only when needed. When the grid loads, I load the first page worth of data. When the next page is clicked, I load the next set of page set of data.

Now I have "multi select" enabled and I thoguht if I would keep the loaded results in memory plus having the selected rows in memory that would be enough to keep the state.

What I want is if you load up the grid and are on page 1, you select 3 rows, and then go to page 2 and then go back to page 1 those 3 rows should still be checked.

Right now when I do this, it is wiped out.

I can't share my code but I did something essentially like the following code.

1. Using SelectedDataItemsChanged, when a row is selected I store it in my State class what has the HashSet property
2. In Dataprovider. I have a dictionary that stores the GridDataProvider result. When I pull back page 1 I store it into this Dictionary, when a user comes back to page 1 I check to see if it exists in my dictonary and if it does then I return that if not I go to the database and grab that "new" page and then store it as well.

<HxGrid MultiSelectionEnabled="true" Responsive="true"  SelectedDataItemsChanged="SelectedChanged"  TItem="CultureInfo" DataProvider="ClientSideProcessingDataProvider" PageSize="10">
    <Columns>
        <HxGridColumn HeaderText="LCID" ItemTextSelector="@(item => item.LCID.ToString())" SortKeySelector="@(item => item.LCID)" IsDefaultSortColumn="true" />
        <HxGridColumn HeaderText="DisplayName" ItemTextSelector="@(item => item.DisplayName)" SortKeySelector="@(item => item.DisplayName)" />
        <HxGridColumn HeaderText="Name" ItemTextSelector="@(item => item.Name)" SortKeySelector="@(item => item.Name)" />
        <HxGridColumn HeaderText="EnglishName" ItemTextSelector="@(item => item.EnglishName)" SortKeySelector="@(item => item.EnglishName)" />
    </Columns>
</HxGrid>

<p>
    Selected culture infos:
    @foreach (var cultureInfo in selectedCultureInfos)
    {
        <span @key="@cultureInfo">&nbsp;@cultureInfo.Name</span>
    }
</p>

@code {
    Dictionary<int, GridDataProviderResult<CultureInfo> MyProperty {get; set;}
    private void SelectedChanged(HasSet<CultureInfo> selected){
            // would call my state here and update the value
           // it would do something like this  StoredSelectedState.UnionWith(selected);
  }

    private Task<GridDataProviderResult<CultureInfo>> ClientSideProcessingDataProvider(GridDataProviderRequest<CultureInfo> request)
    {
           if(MyProperty.ContainsKey(request.StartIndex)){
                   return MyProperty[request.StartIndex]
          }
         else {
                    // call my serever and get data back
                  // store in Dictonary and call it back up if they go back to that page.
                // return new GridDataProviderResult
            }
    }
}

I was hoping this would work as I am storing all the results into a Dictonary even as the GridDataProviderResult and storing all the selected rows. I am not making them "new" or anything so I thought they would be all the same reference.

Yet when I go back to the previous page non onf the selected rows are selected.

I am not sure how to do this.

[benholtsclaw]

Hello dev,

Did you happen to find a workable solution to this problem? I too need to be able to select multiple items from a batch and of course they're not all on one page.

[hakenr]

This feature is tracked as #576, and we aim to make it configurable.
Currently, none of our commercial customers or Premium sponsors/subscribers have requested this feature, so it's waiting in the implementation queue.

[benholtsclaw]

@hakenr - you now have a premium sponsor requesting enhancement / issue #576 :-) I'm happy to support your project. I just really appreciate the attitude you have when replying to discussions and issues. I thought about just going back to Mud when I ran into this issue with the datagrid but after you replied in the kind manner that you did, I didn't have any peace with abandoning Havit. Havit.Blazor is more visually appealing, I enjoy working with Boostrap, and I just appreciate the ethos here. So thanks for all your hard work on this project.

I'm going to post my use case on the issue page.

[hakenr]

@benholtsclaw Thank you for your sponsorship and kind words!
Looks like we'll need to give some attention to that feature now. :-D
Hopefully, we can resolve it today or tomorrow.