Load On Demand Combobox for RadGridView

5 posts, 0 answers
  1. Sean
    Sean avatar
    79 posts
    Member since:
    May 2007

    Posted 14 Jul 2009 Link to this post


    RadControls version

    Q2 2011 SP1

    .NET version


    Visual Studio version


    programming language

    VB.NET and C#

    This project demonstrates "load on demand" functionality for a combobox in the grid.  Although this is available with the controls for ASP.NET, this is not currently supported for the WinForms combobox.

    The application consists of a single RadGridView control with one GridViewMultiComboBoxColumn named "Country".  The load on demand functionality is encapsulated in the LoadOnDemandCellEditor class, which inherits from RadMultiColumnComboBoxElement.  Once the cell is put into edit mode, the default cell editor is changed to the custom cell editor.  This makes use of System.Timer object, which is used to buffer the requests to the web service (included with the project).  Once the timer's interval has passed, it executes an asynchronous web service call to load the matching items.

    When the application runs, a window form is loaded with a RadGridView. The grid contains a list of countries.  Double click on a row to put it into edit mode and clear out the text.  As you type, the combobox makes asynchronous web service calls to retrieve matching items.  So for example if you type in "Mo" it will return all countries that match this (ex. "Morocco", "Monaco").  As you continue typing it will further refine the matching items.

    Hope this is helpful!
  2. Vassil Petev
    Vassil Petev avatar
    1765 posts

    Posted 15 Jul 2009 Link to this post

    Hi Sean,

    Thank you for sharing this project with the community - we are sure that it will be of interest to all Telerik clients. Your account has been updated with 3,000 Telerik Points for sharing your solution.

    Kind regards,
    the Telerik team

    Instantly find answers to your questions on the new Telerik Support Portal.
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  3. Stefan
    Stefan avatar
    2911 posts

    Posted 24 Oct 2011 Link to this post

    Hi guys,

    This project has been updated to Q2 2011 SP1. A C# version was also added to the solution.
    Best wishes,
    the Telerik team

    Q2’11 SP1 of RadControls for WinForms is available for download (see what's new); also available is the Q3'11 Roadmap for Telerik Windows Forms controls.

  4. Ajay
    Ajay avatar
    1 posts
    Member since:
    Jun 2014

    Posted 13 Jun 2014 Link to this post

    I have 200000 records with 10 column. I want to fill record when user start typing or press particular key like F2 in multicolumn combo.
  5. Dess | Tech Support Engineer, Sr.
    Dess | Tech Support Engineer, Sr.  avatar
    4131 posts

    Posted 18 Jun 2014 Link to this post

    Hello Ajay,

    Thank you for writing.

    Currently, GridViewMultiComboBoxColumn does not support load on demand out of the box. You can achieve some kind of a lazy loading using the CellEditorInitialized event and setting up the RadMultiColumnComboBoxElement. In order to detect when the user starts typing in the editable area, you can subscribe to the RadMultiColumnComboBoxElement.TextBoxElement.TextBoxItem.HostedControl.TextChanged event and perform the desired actions. I think that our Performance Boost with Virtual RadMultiColumnComboBox - Quick Loading and Fast Filtering using Trie KB article would be quite useful about the specific case.

    We kindly ask you to post your technical questions/problems in the support ticketing system (http://www.telerik.com/account/support-tickets/available-support-list.aspx) as this is the best way to reach our support staff - the support system assigns a response time for all of your questions, depending on your license and ensures that all questions will reach the respective developers, if needed. Alternatively, you can ask the community for help by posting your question in the online forums (http://www.telerik.com/community/forums.aspx).

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