Issue with Using Immutable Array in RadzenDataGrid Data Property

Radzen.Blazor Components
1

Hi everyone,

I'm having trouble understanding why I can't use an immutable array in the Data property of RadzenDataGrid. Since it implements IEnumerable, I expected it to work. Could someone please explain why this is not possible ?

Thank you!

2

Hi everyone,

I'm detailing my previous post.I've looked into the code, but I'm having trouble understanding the issue because the parameter is an IEnumerable, and ImmutableArray implements IEnumerable.

Example Code:

<RadzenDataGrid AllowVirtualization="true" PageSize="2" Data="@Items" EmptyText="Empty"
                 AllowPaging="true" TItem="CustomClass" AllowFiltering="true" AllowSorting="true">
    <Columns>
        <RadzenDataGridColumn TItem="CustomClass" Property="@nameof(CustomClass.Name)" />
        <RadzenDataGridColumn TItem="CustomClass" Property="@nameof(CustomClass.Description)" />
    </Columns>
</RadzenDataGrid>

@code {
    public class CustomClass
    {
        public CustomClass(string name, string description)
        {
            Name = name;
            Description = description;
        }

        public string Name { get; set; }
        public string Description { get; set; }
    }

    private ImmutableArray<CustomClass> Items = ImmutableArray.Create(
        new CustomClass("test1", "description test1"),
        new CustomClass("test2", "description test2"),
        new CustomClass("test3", "description test3"),
        new CustomClass("test4", "description test4")
    );
}

Exception thrown during render:

blazor.web.js:1 [2025-04-24T12:18:54.608Z] Error: System.ArgumentException: Expression of type 'System.Collections.Immutable.ImmutableArray`1[CustomClass]' cannot be used for parameter of type 'System.Collections.Generic.IEnumerable`1[CustomClass]' of method 'Int32 Count[CustomClass](System.Collections.Generic.IEnumerable`1[CustomClass])' (Parameter 'arg0')
   at Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize`1.BuildRenderTree(RenderTreeBuilder builder)
   at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)
3

ImmutableArray is not IEnumerable:

image
image1920×1080 162 KB

while the DataGrid expects IEnumerable:

4

I spoke too soon. The exception is raised when you attempt to convert this collection to IQueryable and execute Count(). The following code will raise the same exception:

@using System.Collections.Immutable

@code {
    public class CustomClass
    {
        public CustomClass(string name, string description)
        {
            Name = name;
            Description = description;
        }

        public string Name { get; set; }
        public string Description { get; set; }
    }

    private ImmutableArray<CustomClass> Items = ImmutableArray.Create(
        new CustomClass("test1", "description test1"),
        new CustomClass("test2", "description test2"),
        new CustomClass("test3", "description test3"),
        new CustomClass("test4", "description test4")
    );

    protected override async Task OnInitializedAsync()
    {
        await base.OnInitializedAsync();
 
        var count = Items.AsQueryable().Count();
    }
}

This is what the DataGrid is performing with every collection assigned to Data in order to calculate the paging.

5

Hi,

Thank you for your response.

It is the ImmutableArray class, not a generic class.

The ImmutableArray class implements the IEnumerable interface.

image
image1048×877 46.5 KB

6

Yes, I saw that - see my previous reply.

7

Okay, I understand more about the issue, but I have two questions:

  1. Does the Data parameter need to implement IQueryable? Is it not dangerous to perform a cast in the component?
  2. Is it not possible to use the Count method from IEnumerable?
8

AsQueryable() is not a cast.

No, since in this case we need to have separate code with different implementation.

9

Oh, I see. I apologize for not reading your message carefully.

After reviewing the documentation for AsQueryable, I still don't understand why it isn't working.