Telerik Multi Select to have optional top level header item with check box & title "Select All" [Localizable]. 

If all items are selected, the display box of the Multi-Select should show "All Selected" instead of list of selected items.

Description

In Firefox, there are occasions in which multiple items remain focused (k-focus class is not removed from the blurred item)

Reproduction (if bug)

1. Create a multiselect and set AutoClose="false".
2. Open the component and select a few items.
3. Close the component.
4. Open the component and select a new item.
5. Two items have the k-focus class.

Second related case:

1. Create a multiselect and set AutoClose="false".
2. Open the component and navigate up and down with the keyboard arrows.
3. Select an item.
4. The last focused item with the arrows is focused as well as the newly selected item.

REPL for reproduction

Expected (if bug)

Only one item should have the k-focus class at a time.

Browser (if bug)

Firefox

Broken Telerik UI for Blazor version (if bug)

3.5.0

To reproduce:

• Use the Local Data code snippet
• Open the popup
• Scroll down
• Close the popup
• Open the popup again
• Blank space will be rendered above the visible items.

The following, took a bit of effort to identify where the behaviour was failing for a screen reader.

for all scenarios below the multi-select component currently has items (more than one) in it as selected.

GOOD

if keyboard focus is on text edit, and u leave the component (w/ tab key), when revisiting the component (w/ shift+tab keys) all selected items are read out correctly

BAD

if keyboard focus is on selected item, and u leave the component (w/ tab key), when revisiting the component (w/ shift+tab key) the focused (selected) item is not read out correctly.

(sorry example read out not provided)

GOOD

selected items are read out correctly when;

• closing items panel w/ escape key,
• closing items panel when selecting an item
  

BAD

delete item;

• remove all selected items w/ escape key does not inform a screen reader user of the outcome; that no item is now selected (should state something).

• removing last item with backspace does not inform screen reader of the outcome; that no item is now selected (should state something). I swear this worked once with firefox.
  

the following behaviour also occurs after removing all items via a keyboard, the keyboard focus becomes lost;

• (BAD) most times u can't press a right / down key into the text section of the multi-select (experienced w/ firefox too)
• (GOOD) most times can press alt+down to bring the panel (experienced w/ firefox too)
• (GOOD) u can still tab out to next clickable object

Hi,

When displaying a MultiSelect control on a TelerikWindow (modal), the dropdown of items is displayed behind the dialog:

How can I change the Z-Index of the dropdown?

This appears to be documented behavior, but it also seems to me like this is something that the component should be handling.

When using row virtualization with a Grid, a DropDownList, a MultiSelect, etc, the OnRead is called for every scroll event, regardless of whether the component _actually_ needs to fetch new data or not.

For example:  A DropDownList with a PageSize of 100, but with only 10 items visible in the dropdown at a time will ask for 100 records every time the user even scrolls 1 record down. This results in many requests to the backend server, with many of the results being the majority of the contents from the previous request.

I have worked around this by implementing a buffer that keeps results for me and returns them as the user scrolls, only requesting for more from the backend server when the buffer runs out, but this feels like something that the components themselves should be handling.

If this is expected behavior, all good.  Just wanted to raise some awareness on it.

Using row virtualization on MultiSelect, and am attempting to put a loading indicator into the popup content if the request to the server is still ongoing.

Problem with this is that the popup contents don't update if the popup is open when loading finishes.  I put together a reproduction on Telerik REPL showing the behavior I am experiencing.

https://blazorrepl.telerik.com/mvvQvVvN2458vinQ36

Note, Options finish loading (seen by the div update above the MultiSelect component), but if the popup is open, the contents do not update to reflect the loaded options.

My current workaround is to just make the MultiSelect disabled while it is doing its initial load.

When user is inside list of selected options/items, navigating amongst the items with keyboard left/right keys, it states "item # of # of items of level 1". 
what is "of level 1"? (is items selected in level 1 and level 2 is the text editable section?)

i am expecting the screen reader to state item "<value/label/title>" when i set focus to an item via keyboard left or right.

The issue did not occur in firefox. Sorry, i have not provided the firefox readout w/ the screen reader for comparison.

however, for the most likely user scenario the behaviour with the screen reader is correct.

if keyboard focus is on text edit, and u leave the component (w/ tab key), when revisiting the component (w/ shift+tab keys) all selected items are read out correctly

tested in Chrome and firefox using NVDA.

Hi team,

I just upgraded Blazor version to 2.25 and the primary button in FooterTemplate of MultiSelect started behaving differently. This was shown correctly prior to update. Also, normal button where Primary="true" is shown with correct styling.

I have written a little code snippet to demonstrate.

As it can be seen the the code for button is exactly same in both places but the output is different.

Please have a look into this.

Many thanks,

Hi,

I would like checkbox support including the check all checkbox on the multiselect component like: https://docs.telerik.com/devtools/aspnet-ajax/controls/combobox/functionality/checkbox-support

The url below shows how to create custom checkboxes in the multiselect component but adding a check all checkbox in the headertemplate does not update the multiselect popup

https://docs.telerik.com/blazor-ui/knowledge-base/multiselect-checkbox-in-dropdown?_ga=2.50111909.206897922.1631541466-694624900.1630583797&_gac=1.246637872.1631604077.EAIaIQobChMI8PnX6Pb98gIVkwCLCh381AjMEAAYASAAEgLROPD_BwE

In drop down panel colour indicates which option has been selected (is it the dark colour or is the light colour). Suggestion: having an icon of tick would assist.

As an alternative option - Blazor MultiSelect - Templates | Telerik UI for Blazor this would be great if you could template selected and non-selected items, but at the moment there is just the one item template.

When re-visiting the input when it has options selected as badges, using keyboard;

• to move between badges it say 'blank' (see: Multiselect options read as blank by AT [WCAG 1.3.1 level A] (telerik.com))
• does not tell you what you have already selected (if you don't tab to input and just use up or down it will read the options)
• adding and removing items the user is not informed how many options have been selected

First visit of options in drop down, using keyboard:

• each option is read as 'blank' in screen reader
• number of options not read out

At the moment, the OnChange even fires when:

• the user selects an item from the dropdown
• the user blurs the input
• the user presses enter in the input

The problem with the multiselect is that we have two extra actions:

• remove an already selected item from its own [x] button - OnChange does not fire even though the value changes
• clear all items with the ClearAll button - OnChange does not fire even though the value changes
• delete items with the backspace key

Based on my testing and the online demos, each selection of an item in the dropdown for the Blazor MultiSelect closes the dropdown.

Is there a way to keep the dropdown open for the user to make multiple selections? The user could then click outside of the dropdown to close the dropdown.

The behavior I am describing is similar to the Kendo UI for jQuery MultiSelect "autoClose" configuration property.

https://docs.telerik.com/kendo-ui/api/javascript/ui/multiselect/configuration/autoclose

I have a custom ICollection which I wanted to use with the MultiSelect control, however, the Value property is of type List<T>. This is very restrictive; the property should implement an interface for flexibility.

ADMIN EDIT: When voting, please add your comment on what you would prefer so we can gauge the needs people have and act accordingly.

Hi

Recently we were building a feature that allows the optional selection of multiple items, and decided to use the Telerik Multiselect component. A subcomponent of the feature reads from a file, and pre-selects items in the multiselect based on data in the file similarly to this sample:

foreach(string item in file)
{
    selectedItemsList.Add(item);
}

At the moment, however, it seems that the Telerik Multiselect does not refresh its state when selected items are added and removed programatically, only when they are added or removed via user interaction. Would it be possible to have the Telerik Multiselect support the usage of ObservableCollection?

Thanks in advance!

Michael