Hi Telerik Team,

One of the requirements for my team project is that the ComboBox needs to be sorted in descending order to list dates. We need to sort the groups and the options inside the groups.

Ideally, the ComboBox can have a SortDirection parameter that defines the order as SortAscending or SortDescending, and can display the ComboBox groups and options accordingly.

===

Admin Edit:

It would be useful if you could disable the default sorting of the groups as well.

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.

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.

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.

I have a ComboBox/DropDownList that gets data from a remote service, using virtualization. When the PageSize property is big enough (in my case 20), I have issues scrolling up the selection box dropdown list. I'm trying to scroll but then resets to the currently selected item making it almost impossible to scroll up. You can use your own demo examples to replicate this issue.

To reproduce the issue, try the ComboBox - Virtualization, in Telerik REPL (Demo), change the PageSize from 10 to 20. Open the dropdown and select an item. Then, open again the dropdown and scroll slowly up.

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 am working on a form where experienced agents need to input data quickly. Often enough they know the codes and so they can type them in the combo box, but they shouldn't have to look for the mouse to select the item, the combo box should select it when the user presses Tab to move to the next field.

This should happen only when the user has filtered the combo box so they see some items (and so the dropdown is open) - I want them to be able to select only items from the available options, AllowCustom does not work for me.

---

ADMIN EDIT

Here is one workaround you can consider:

https://blazorrepl.telerik.com/QoOAPyEZ233YP2AX19

@inject IJSRuntime js

@* Move this script to a separate JS file *@
<script suppress-error="BL9992">
    function getHighligtedComboItem() {
        // Get the currently focused item in this particular ComboBox.
        var focusedItem = document.querySelector(".select-on-tab .k-list-item.k-focus");
        if (focusedItem) {
            return focusedItem.innerText;
        }
    }
</script>

<p>FirstFilteredItem: @FirstFilteredItem</p>

<p>Selected value: @ComboBoxValue</p>

<span onkeyup="@GetFirstFilteredItem">
    <TelerikComboBox Data="@ComboBoxData"
                     Value="@ComboBoxValue"
                     ValueChanged="@( (int newValue) => ComboBoxValueChanged(newValue) )"
                     TextField="@nameof(ListItem.Text)"
                     ValueField="@nameof(ListItem.Value)"
                     Filterable="true"
                     FilterOperator="@StringFilterOperator.Contains"
                     OnBlur="@SelectItemOnTab"
                     OnOpen="@( () => IsComboBoxOpen = true )"
                     OnClose="@( () => IsComboBoxOpen = false )"
                     Placeholder="Select an item..."
                     ClearButton="true"
                     Width="200px">
        <ComboBoxSettings>
            <ComboBoxPopupSettings Class="select-on-tab" />
        </ComboBoxSettings>
    </TelerikComboBox>
</span>

<input placeholder="another form element" />

@code {
    private IEnumerable<ListItem> ComboBoxData = Enumerable.Range(1, 123).Select(x => new ListItem { Text = "Item " + x, Value = x });

    private int ComboBoxValue { get; set; }

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

    private bool IsComboBoxOpen { get; set; }

    private async Task GetFirstFilteredItem(KeyboardEventArgs args)
    {
        if (!IsComboBoxOpen)
        {
            // Wait at least 300ms, which is the opening animation.
            await Task.Delay(400);
        }
        else
        {
            // Wait, depending on the typical filtering time.
            await Task.Delay(300);
        }

        // The code that will find the item text depends on the exact scenario and potential use of ItemTemplate.
        FirstFilteredItem = await js.InvokeAsync<string>("getHighligtedComboItem");
    }

    private void SelectItemOnTab()
    {
        if (!string.IsNullOrEmpty(FirstFilteredItem))
        {
            // Match the filter operation to the filter operator of the ComboBox.
            var matchingItem = ComboBoxData.Where(x => x.Text.ToLowerInvariant().Contains(FirstFilteredItem.Trim().ToLowerInvariant())).FirstOrDefault();
            if (matchingItem != null)
            {
                ComboBoxValue = matchingItem.Value;
                FirstFilteredItem = string.Empty;
            }
        }
    }

    private void ComboBoxValueChanged(int newValue)
    {
        ComboBoxValue = newValue;
        FirstFilteredItem = string.Empty;
    }

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

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.

The popup window is not closed when the ComboBox is disabled from code.

Reproduction code:

Selected value: @selectedValue
<br />

<TelerikComboBox Data="@myComboData"
                 TextField="MyTextField"
                 ValueField="MyValueField"
                 Value="selectedValue"
                 ValueChanged="@((int value) => ValueChangedHandler(value))"
                 Placeholder="Select an item..."
                 ClearButton="true"
                 Enabled="@isEnabled"
                 Filterable="true">
</TelerikComboBox>

@code {
    public bool isEnabled { get; set; } = true;
    IEnumerable<MyDdlModel> myComboData = Enumerable.Range(1, 20).Select(x => new MyDdlModel { MyTextField = "item " + x, MyValueField = x });

    int selectedValue { get; set; } = 3; //usually the current value should come from the model data

    public async Task ValueChangedHandler(int value)
    {
        isEnabled = false;
        await Task.Delay(4000); //simulate network delay

        selectedValue = value;

        isEnabled = true;
    }

    //in a real case, the model is usually in a separate file
    //the model type and value field type must be provided to the dropdpownlist
    public class MyDdlModel
    {
        public int MyValueField { get; set; }
        public string MyTextField { get; set; }
    }
}

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

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 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. 

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

Hello,

 iam found "strange" behaviour compared to previous versions in combobox, with custom paging, filtering, valuemapper.

"simple description":
- Do not call OnRead and ValueMapper AFTER clicking/selecting the ITEM in any case(after filtering, or after scrolling...). Do it same way as selecting WITHOUT prior filtering.

Complex test

A sample for testing is here(and comments inside):
https://blazorrepl.telerik.com/GGPwalvk09g228sm32

How to reproduce:

1 - start = value is PREselected - OK
2 - clear the combobox - OK
2 - input value 40  - slowly do not rush, number by number - OK
3- wait 2 seconds and Click/select item ("Name 401" etc) - NOK
observe the events fired(Exception/info: time - indicates that OnRead was fired again) 

Repeat the same WITHOUT filtering, just scrolling
observe the events fired = looks ok (Exception/info: time)

When selecting item by CLICKING on it(after filtering) looks like those events are fired:
- ValueMapper (why?)
- OnRead again(why again?)
- bind value (ok)
and sometimes ValueMapper again
it depends of "timing"

expected:
When selecting item by CLICKING on it:
- BIND the value. Everything is in there(no reason to call OnRead or ValueMapper)

Related, unexpected(video attachment):
Also when working in "real" scenario, AFTER clicking on item AFTER filtering, it returns full MODEL assembly path into to input filed, instead of clicked item
Lets have a list: {Name of the item,Another item,Next item}
entere in combobox/filter "name", results are shown ok, clicked on one and result shuld be ("Name of the item"), after clicking it returns "base model class name"
ie: "inwApp1.Pages.prozam.crm.EdcrmOrg+BaseKeyModel" - you dont want to see this :) .

There is different event orders for those 2 scenarios(it should be the same for both as at point 1) ):
1) when SELECTing item without filtering(just moving with scrollbar down to value 401 (only with onread and virtual paging)) = OK
2) when filtering by value "40" and SELECTing item by clicking on it - NOT OK = it look like this causes the problems and subsequent event calls

Is there any workaround, or new "property" to set? Thanks