The ComboBox and MultiComboBox replace the current filter value with the component value during virtual scrolling.

The issue is similar to MultiColumnComboBox and ComboBox remove filtering value after virtual scrolling , but the other issue occurred when there was no current value.

To reproduce:

1. Go to https://demos.telerik.com/blazor-ui/combobox/virtualization
2. Select item Changde
3. Filter by "Ch"
4. Scroll down

Ch will be replaced by Changde.

If custom values are not required, a possible workaround is to use a filterable DropDownList with virtualization.

For the MultiColumnComboBox, the component can use a RowTemplate to simulate multiple columns in the dropdown. You can see a REPL example here.

I want to access runtime the value by which the user filters. 

===ADMIN EDIT===

Use the OnRead event handler to access the filter value:

@using Telerik.DataSource
@using Telerik.DataSource.Extensions

<TelerikComboBox OnRead="@OnComboBoxRead"
                 TItem="@ListItem"
                 TValue="@int"
                 @bind-Value="@SelectedValue"
                 TextField="@nameof(ListItem.Text)"
                 ValueField="@nameof(ListItem.Id)"
                 Filterable="true"
                 FilterOperator="@StringFilterOperator.Contains"
                 Width="300px">
    <ItemTemplate>
        @HighlightResult(context.Text)
    </ItemTemplate>
</TelerikComboBox>

<style>
    .k-list-item:has(u) {
        gap: 0;
    }
</style>

@code {
    private List<ListItem> ListItems { get; set; } = new();

    private int SelectedValue { get; set; } = 3;

    private string ComboBoxFilterValue { get; set; } = string.Empty;

    private async Task OnComboBoxRead(ComboBoxReadEventArgs args)
    {
        ComboBoxFilterValue = args.Request.Filters.Cast<FilterDescriptor>().FirstOrDefault()?.Value.ToString() ?? string.Empty;

        DataSourceResult result = await ListItems.ToDataSourceResultAsync(args.Request);

        args.Data = result.Data;
        args.Total = result.Total;
    }

    public MarkupString HighlightResult(string text)
    {
        var result = string.IsNullOrWhiteSpace(ComboBoxFilterValue)
            ? text
            : text.Replace(ComboBoxFilterValue, "<u>" + ComboBoxFilterValue + "</u>", StringComparison.OrdinalIgnoreCase);

        return new MarkupString(result);
    }

    protected override void OnInitialized()
    {
        ListItems = new List<ListItem>() {
            new ListItem(1, "Basketball"),
            new ListItem(2, "Golf"),
            new ListItem(3, "Baseball"),
            new ListItem(4, "Table Tennis"),
            new ListItem(5, "Volleyball"),
            new ListItem(6, "Football"),
            new ListItem(7, "Boxing"),
            new ListItem(8, "Badminton"),
            new ListItem(9, "Cycling"),
            new ListItem(10, "Gymnastics"),
            new ListItem(11, "Swimming"),
            new ListItem(12, "Wrestling"),
            new ListItem(13, "Snooker"),
            new ListItem(14, "Skiing"),
            new ListItem(15, "Handball"),
            };

        base.OnInitialized();
    }

    public class ListItem
    {
        public int Id { get; set; }
        public string Text { get; set; } = string.Empty;

        public ListItem(int id, string text)
        {
            Id = id;
            Text = text;
        }
    }
}

Please add a way to add, if it is missing in the item list, and set the selected item of a combobox programmatically. This will spare the need to call the remote source and have duplicate data.

Example: if you choose a city from a combobox and the city has all the information about the province, the province combobox should populate with the correct data without needing to call the remote source.

An Implementation of this could be:

public void SetSelectedItem(TItem item)
{
    if (item == null)
    {
        ClearButtonClick();
    }
    else
    {
        ListDataItem clonedItem = CreateDataItem(item.Clone());

        var dataItemToSelect = DataItems.FirstOrDefault(x => x.Value.Equals(clonedItem.Value));
        if (dataItemToSelect == null)
        {
            dataItemToSelect = clonedItem;
            AddCustomValue(dataItemToSelect.Text, dataItemToSelect.Value, dataItemToSelect.DataItem);
        }

        SelectItem(dataItemToSelect);
    }
}

I am using ComboBox and I want to be able to filter by two model properties. To achieve this I have implemented custom filtering through the OnRead event. Additionally, I am ordering the data to first match the results from the one property, which also is used for the TextField, and after that to match the results from the other property. However, when the results are only from the match of the second property, there is no focus.

Here is a REPL example https://blazorrepl.telerik.com/wyaMQhEN108axXJ036 

Steps to reproduce the issue:

Type "a": "Value test - ano" has the focus (the first option in the list)

Type "an": "Value test - ano" receives the focus (the first option in the list)

Type "ano": "Value test - ano" receives the focus (the first option in the list)

Type "anot": no item has focus despite the results being only "Another Value - val"

The problematic behavior appears in this specific scenario:

• AllowCustom="true".
• The input partially matches an item in the list.
• The user presses Enter

In this case, the custom typed value is lost and the component value is the first item in the list matching the input. Thus, the user cannot set their desired custom value.

Reproduction with steps listed inside: https://blazorrepl.telerik.com/GokVlXEW12KGZ36F15.

===

ADMIN EDIT

===

A possible option for the time being:

• Enable filtering.
• Use the OnRead event to get the input value from the filter descriptors and save it.
• In the OnChange event that is triggered on Enter press, set the saved input value to the component.

Here is a basic sample: https://blazorrepl.telerik.com/wourlNOC51FRcNAX54.

An open ComboBox will not close when the user tabs out of it when the ComboBox is the last component on the page. Here is a test example: Creating Blazor ComboBox

If there is another component after the ComboBo, then tabbing out works correctly.

When using the OnRead event of the ComboBox there is no way to retrieve the selectedItem because the list of items that is populated is internal.

There are 2 workaround but they are not ideal:

- Saving the list of items returned by the OnRead event into a parallel list and then retrieve the selectedItem from it -> the problem is that there will be 2 identical lists in memory and, if scaled, might cause problems:

CachedSitesList = result.Items;

args.Data = result.Items;
args.Total = (int)result.TotalCount;

- Retrieving the selectedItem by calling the DB using the Id of the item -> the problem is that it's one more request to add to the DB and the performance is going to decrease if scaled, also it seems useless as the item is already present in memory.

We suggest adding a function to return the selectedItem to improve performance and scalability of the component.

Reproduction: https://blazorrepl.telerik.com/cHbFYUFq53Ext4Yt24.

Steps to reproduce:

1. Open popup.
2. Use the keyboard to navigate to the first item.
3. Type "1", so the input value is "item11" (a value that matches an item from the list) -> ValueChanged is not fired.
4. Type "1" again, so the input value is "item111" (this is a custom value not present in the list) -> ValueChanged is fired.
5. Delete the last "1", so the input value is again "item11"(a value that matches an item from the list) -> ValueChanged is not fired.

===

TELERIK EDIT: A possible workaround is to obtain the typed string in OnChange and check if it is matching an item in the datasource:

https://blazorrepl.telerik.com/QyPEQXkV25A7VFyf50

When the option "AllowCustom" is enabled for a TelerikComboBox and the user types something above a certain speed, typed characters are lost. Here is a GIF showing the problem on the page https://demos.telerik.com/blazor-ui/combobox/custom-values – I typed "123456", but end up with "1246" instead. In between the input field is showing some weird glitching.

Is there a way to have the TelerikComboBox behave normally, as it apparently did in versions prior to 4.3.0? We noticed this behavior only some time after upgrading from version 4.0.1, where everything still works properly.

I'd like to report a bug with the Telerik combo box opening animation.

The problem can be reproduced on your page https://demos.telerik.com/blazor-ui/combobox/templates

Reproduction steps

1. Open page https://demos.telerik.com/blazor-ui/combobox/templates
2. Change the window to restored mode
3. Open the Product combo box and observe that the popup animation works as expected
4. Resize the window slightly vertically
5. Open the Product combo box
6. Observe that the combo box popup animation starts in the wrong place

This issue is 100% reproduceable every time and also can be reproduce if the popup is opened and the window is maximized.

Please see the attached video from about 15 to 25 seconds. Note that I reproduce the issue in the video a couple of times however due to the quality of it you can only see the incorrect animation between 15 to 25 seconds.

I hope the information helps.

The tablet that I am using is slightly wider than the medium breakpoints set in AdaptiveMode.Auto. However, I still want to show the action sheet. I'd like to be able to configure the breakpoints which are currently hard-coded.

===

ADMIN EDIT

===

The request is opened for ComboBox but it also targets other selects and pickers that have AdaptiveMode feature. For example, DropDownList, MultiSelect, DatePicker and more.

When the height of the popup is set to 'auto' and it opens upwards, the resizing process causes it to be incorrectly positioned.

# Reproduction:

1. Open this REPL - https://blazorrepl.telerik.com/mHuoPRFk52ienlUt52
2. Shrink the browser so that the ComboBox remains at the bottom of the window: 


3. Type "item 2" in the ComboBox

Description

When selecting a value via the keyboard, the input element is out of sync.

Reproduction (if bug)

1. Create a Combobox and populate it with data.

2. Trigger a change with the keyboard.

3. The value is updated but the input holds the old value and is out of sync.

REPL for reproduction:

https://blazorrepl.telerik.com/GnEnPZun00tsuQEA47

When selecting an item with the Enter key, the value is not displayed in the input field.

1. Open this REPL example
2. Open the ComboBox and navigate with the arrows to any item
3. Hit "Enter" to select the item

The item is selected, but its value is not displayed inside the input field.

===

The issue is also reproducible with the MultiColumnComboBox component. 

When the user selects a value and then focuses on another component the OnBlur of the ComboBox is not triggered. The issue is reproducible in the Firefox browser (tested with version 109.0).

To reproduce the issue open the following REPL example in the Firefox browser:
https://blazorrepl.telerik.com/mdklmHYN06lVQjyL26

Select a value in the first ComboBox and then focus on the second ComboBox. The OnBlur event should trigger.

Hi,

EDIT: This issue (of course) relates to the case where the combobox has data selected when rendering.

The clear button of the combobox behaves in a way that I find strange, and which prevents us to get the desired behaviour in our application.

It is easily reproducable with your demo here:

https://demos.telerik.com/blazor-ui/combobox/templates

When loading the page there is no clear button, which I think is wrong. Especially since it is not even in the DOM, so it cannot be made visible with styling. When clicking in the field, the clear button appears, and it stays there when changing focus to elsewhere, which seems inconsistent.

In other words, the span of the button (in the red box below) only appears when the combobox has had focus.

Thanks,

Niels

I would like the ability to flag elements in a data bound combo that are no longer available as disabled and not selectable.  Had they been previously selected, they still need to show, but should not allow a user to select it again.

I would like a property that can be set when databinding a combo.

For instance when you set the Data, TextField, & ValueField properties, can there also be one for SelectableField (or something) - this could be mapped to a Boolean in the dataset.

If this property isn't used then it defaults to yes (ie they are all selectable), but if it is used, then any items which have this field set to 'no' then they show as a different color (could just be grey) but are not selectable by the user.

If they had previously been selected (prior to being marked as no longer available) then they should show when the record is loaded, but otherwise they are not selectable.

I don't particularly want to write code on click to see if its enabled and then unselect it, I would prefer it to simply be built into the base control.

Is this possible?  Or is there another property already there that does this?