Based on customer feedback:

The RadFormDecorator decorates most native input controls, but does miss some, namely in ComboBox and ListBox.

As this [the lack of decoration] is something advertently done, due to various issues in different browsers, we should thread carefully.

Why don't you include a boolean property to show selected image inside input ?

This is already a code library to do it :
http://www.telerik.com/support/code-library/show-the-selected-item-image-in-input

In a FormView, a routine scenario is to provide a control that has some sort of picklist (either DropDown or ComboBoxList) that may be tied to a field that contains a DBNull.

An example might be where one of the fields in the Telerik Profile specifies their favorite Telerik Product (KendoUI, ASP.NET AJAX, etc.).  However, their might be profiles where the user has not selected a favorite product.  Assuming that the Product list comes from a related table, then this field (say, FavoriteProductId) in the Profile would contain a DBNull.

I would like Telerik to add "declarative" functionality on the RadComboBox and RadDropDownList to handle the case where SelectedValue = DBNull.

Below is an example of what this might look like for a RadComboBox (inside of a FormView -- note: only showing the RadComboBox declaration).

<telerik:RadComboBox Style="z-index: 9100"  ID="rcbFirstOrder" runat="server" Width="50px" SelectedValue='<%# Bind("FirstOrder") %>'     HandleDBNull="true" >
    <Items>
        <telerik:RadComboBoxItem runat="server" Text="" Value="DbNull (or Null or Nothing)" />
        <telerik:RadComboBoxItem runat="server" Text="No" Value="0" />
        <telerik:RadComboBoxItem runat="server" Text="Yes" Value="255" />
    </Items>
</telerik:RadComboBox>

Notice the new property ---    HandleDBNull = true       and the ability to define the value on a RadComboBoxItem as DBNull (or null or nothing) -- some string to define DBNull.

Although the above example shows all the RadComboBoxItems defined declaratively, this scenario could easily be extended to use AppendDataBoundItems = true and the non-DBNull values to come from a Data Source.

Thanks for taking the time to consider this functionality.  This enhancement would remove all of the code-behind tweaks that are currently incorporated to use a ComboBoxList / DropDownList with a database field that can contain DBNull.

The input box (TextBox) portion of the Rad Combo box could benefit from the ability to customize/format the data presented within said element.  Having the ability to toggle it to a multi-line TextBox would aid in this ability as well.  Having the ability to implement custom html in the form of a template, perhaps a SelectionBoxTemplate, would open the control of the display to be completely customizable.

Please consider this enhancement in a future release.

Thanks...

FYI: this is basically an edit of a previous post.  Original didn't allow edits.

Please add a Server Side event for OnBlur or OnClose for the RadComboBox with the option for an auto postback.

The Telerik support team suggested using the "TextChanged" event.

However, this does not work for my purpose and here is why:

Mainly because it appears that an event fires immediately after each check/uncheck.

I have been using a dropdowncheckbox control by another vendor in multiple projects over the past 3 years (many, many instances).  It fires an event when you click anywhere out side the dropdown or when you collapse the dropdown (close).  This is perfect because many of these dropdowns supply parameters to SSRS reports that are generated on the webpage and I can iterate through the object and process all of the items that are checked at the same time, pass all parameters to the various reports.

Users of these website have requested that after selecting (checking) which values they want to choose, they want the reports to run automatically and don't want to click a "Run reports" button. I am doing this currently with the other control.

*** How could I possibly determine when the user is done checking/unchecking items using the "TextChanged" event?  

With an OnBlur or OnClose event it's a No-Brainer.  Event --> Do Processing...

Our company made a decision to standardize our tool set and picked Telerik as that toolset vendor.  The lack of having an event that fires similar to the control that I have been using in the past will require unnecessary code modification.

In summary, if there was a similar event I could simply rename each instance of my C# event handlers (methods) across all projects, then modify that code to iterate through the RadComboBox instead of the control I currently use and be done.  Find --> Replace, mostly. 

For the one (1) instance of the RadComboBox that I have tried I was able to create a work-around by placing code in the IsPostback of the Page_Load event and iterate through the radcombobox, getting the checked values and then doing whatever processing  needs to be done.  This not work for most of the pages in my projects mentioned above due to different circumstances.

Thanks!

Browser:

Microsoft Edge 44.18362.449.0

Telerik Control:

RadCombobox

Teleri Version:  Version=2017.3.913.45,

Issue:

When a item is selected and a postback is occured, the SelectedValue returns an empty string.

Expected behavior:

The correct SelectedValue should be return.

Thing that have been tried so far:

1: upgrade the telerik to the latest version (2020.114) ---> issue persists

2: set autopostback to "true" problem solved

3: use other browsers (chrome, FireFox, new Version 79.0.309.68 ) issue disappears

Sample code: 

1: aspx

2: code behind

If a combobox uses load-on-demand and an item is selected, after postback the item list will be filtered to only items that contain the text of the selected item.  This type of filtered loading is desirable when the user is typing into the combobox and is expecting a reduced item list.  However it can be unexpected behavior if an item is selected, the user was not typing into the combobox, a postback occurs, and then the item list has been reduced.

This video demonstrates the current behavior:
http://screencast.com/t/NVkDc3KYR

And so my request is for the combobox items list to remain the same after postback when the user did not intend for the item list to be reduced.

add ability for radcomboboxitem to expose the attributes collection for the selected item when client-side binding occurs via a webservice.  (based on support id 87724).  Currently only selected text and values are accessible when posted back.  The attributes related to the selected item are as important to provide proper context once on the server side.  Again, this only necessary for the selected item, not all items as I understand the ramifications to client side performance.

Add ability to filter with accent sensitive, IsAccentSensitive property  (like the existing IsCaseSensitive).

In ComboBox If somehow focus is moved to dropdown element (e.g. when user clicks on a header, or on load more items button) then arrow keys and keyboard support won't work anymore.
It can be fixed by simply setting dropdown tabindex to say 1 and attaching ComboBox's own _onKeyDown handler to dropdown keydown too.

Having a RadCombobox on a form and assign a EmptyMessage later containing a diacritical character, the EmptyMessage is treated like it has been entered as a value.
So it will make a call to the webservice using that value which it should not do.

Code example:
        protected void TestLinkButton_Click(object sender, EventArgs e)
        {
            this.CountryComboBoxControl.EmptyMessage = "Bitte wählen Sie ein Land*";
        }

When combo popups to the top of the page it goes out of the browser viewport.
Reproduce: 
A RadComboBox on the bottom of your page and the page height is larger than the viewport.
When you scroll down the page to the RadComboBox and open it the itembox (100+ items) height will be higher than the view port.
See attachment 'RadComboBox.png'

Also the auto shrink doesn’t work in this situation see attachment RadComboBox2.png

Selecting an item from the RadComboBox and then pressing Enter key, does not trigger the default button(if set) of the form/panel in IE and Chrome. The workaround is to handle the client-side OnClientKeyPressing event of the RadComboBox and manually trigger the clicking of the default button.For example:

ASPX:

    <asp:Panel ID="Panel1" runat="server" DefaultButton="RadButton1">
        <telerik:RadTextBox ID="RadTextBox1" runat="server">
        </telerik:RadTextBox>
        <asp:Label ID="Label1" Text="" runat="server" />
        <telerik:RadButton ID="RadButton1" runat="server" OnClick="OnClick1" Text="Click" />
        <telerik:RadComboBox ID="RadComboBox1" runat="server" OnClientKeyPressing="OnClientKeyPressing">
            <Items>
                <telerik:RadComboBoxItem Text="text1" Value="val1" />
                <telerik:RadComboBoxItem Text="text2" Value="val2" />
                <telerik:RadComboBoxItem Text="text3" Value="val3" />
            </Items>
        </telerik:RadComboBox>
    </asp:Panel>

JavaScript:
    <telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">
        <script type="text/javascript">
            function OnClientKeyPressing(sender, args) {

                if (args.get_domEvent().keyCode == 13) {
                    $find("<%=RadButton1.ClientID %>").click();
                }
            }
        </script>
    </telerik:RadCodeBlock>