RadzenDropDown doesn't display values inside the dropdown when cleared when using AllowVirtualization #1111

New Issue

claunia · 2026-01-29T17:49:05Z

claunia commented

2026-01-29 17:49:05 +00:00

Originally created by @egans146 on GitHub (Jan 30, 2024).

Describe the bug
When a RadzenDropDown with AllowVirtualization is provided a value before the user selection and the value is cleared, the dropdown doesn't display any values when opened.

<RadzenDropDown @bind-Value=Value
                Data="items"
                Count="itemCount"
                LoadData="OnLoadData"
                AllowFiltering=true
                AllowClear=true
                TextProperty="@nameof(Item.Value)"
                AllowVirtualization=true />

@code {
    class Item(string value) { public string Value { get; } = value; };

    RadzenDataGrid<Item> grid;

    int itemCount = 1000;

    IReadOnlyList<Item> itemSource;
    Item Value;

    protected override void OnInitialized()
    {
        var charset = "abcdef ".ToCharArray();
        var items = Enumerable.Range(0, itemCount)
            .Select(e =>
            {
                Random.Shared.Shuffle(charset);
                return new Item(new string(charset));
            })
            .ToArray();
        itemSource = items;
        Value = items.First();
    }

    IEnumerable<Item> items;

    void OnLoadData(LoadDataArgs args)
    {
        IEnumerable<Item> query = itemSource;

        if (args.Filter != null)
            query = query.Where(e => e.Value.Contains(args.Filter));

        itemCount = query.Count();
        items = query.Skip(args.Skip ?? 0).Take(args.Top ?? 10).ToArray();
        StateHasChanged();
    }
}

In the example, if the dropdown is opened prior to clearing the value, the dropdown shows the values as intended.

Desktop:

OS: Windows
Browser: Brave
Version 4.24.4

Originally created by @egans146 on GitHub (Jan 30, 2024).  **Describe the bug** When a RadzenDropDown with AllowVirtualization is provided a value before the user selection and the value is cleared, the dropdown doesn't display any values when opened. ```razor <RadzenDropDown @bind-Value=Value Data="items" Count="itemCount" LoadData="OnLoadData" AllowFiltering=true AllowClear=true TextProperty="@nameof(Item.Value)" AllowVirtualization=true /> @code { class Item(string value) { public string Value { get; } = value; }; RadzenDataGrid<Item> grid; int itemCount = 1000; IReadOnlyList<Item> itemSource; Item Value; protected override void OnInitialized() { var charset = "abcdef ".ToCharArray(); var items = Enumerable.Range(0, itemCount) .Select(e => { Random.Shared.Shuffle(charset); return new Item(new string(charset)); }) .ToArray(); itemSource = items; Value = items.First(); } IEnumerable<Item> items; void OnLoadData(LoadDataArgs args) { IEnumerable<Item> query = itemSource; if (args.Filter != null) query = query.Where(e => e.Value.Contains(args.Filter)); itemCount = query.Count(); items = query.Skip(args.Skip ?? 0).Take(args.Top ?? 10).ToArray(); StateHasChanged(); } } ``` In the example, if the dropdown is opened prior to clearing the value, the dropdown shows the values as intended. ![Animation](https://github.com/radzenhq/radzen-blazor/assets/6442594/d3ef5044-3c7c-4308-ba46-262e6e493a90) **Desktop:** - OS: Windows - Browser: Brave - Version 4.24.4

claunia closed this issue

2026-01-29 17:49:05 +00:00

claunia commented

2026-01-29 17:49:05 +00:00

@enchev commented on GitHub (Jan 31, 2024):

Unfortunately I was not able to reproduce this using our demos

Maybe I'm doing something wrong?

@enchev commented on GitHub (Jan 31, 2024): Unfortunately I was not able to reproduce this using our demos ![dd-async](https://github.com/radzenhq/radzen-blazor/assets/5804953/5f111fb1-68fa-45ae-a675-dc305e088145) Maybe I'm doing something wrong?

claunia commented

2026-01-29 17:49:05 +00:00

@egans146 commented on GitHub (Jan 31, 2024):

Thank you for taking the time to investigate the issue.
Here are the steps to reproduce with the example provided:
1: Load the page containing the component.
2: Clear the drop-down value.
3: Open the drop-down.

@egans146 commented on GitHub (Jan 31, 2024): Thank you for taking the time to investigate the issue. Here are the steps to reproduce with the example provided: 1: Load the page containing the component. 2: Clear the drop-down value. 3: Open the drop-down.

claunia referenced this issue

2026-01-29 18:19:13 +00:00

[PR #1111] [CLOSED] Added demo datagrid save settings to url #2516

claunia referenced this issue

2026-01-29 18:19:13 +00:00

[PR #1111] Added demo datagrid save settings to url #2518

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