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Version Q2 2011 released 07/12/2011
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FileExplorer / Custom File Content Provider

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Max file size allowed:
200.00 KB
File extensions allowed:
*.jpg, *.jpeg, *.gif, *.png
Preview

  • Database File Provider

    This example demonstrates the implementation of a custom FileBrowserContentProvider, using a SQL database as a file source. If you have installed the RadControls demo, the DBContentProvider class is available in the App_Code\Editor\ folder of the demo project or in this code library.

    Custom FileBrowserContentProvider implementation allows using virtually any type of file sources for the RadFileExplorer:

    • Database
    • Custom role-based CMS system
    • Web service
    • Applications which use URL Rewriters
    The DBFileBrowserContentProvider class inherits the abstract Telerik.Web.UI.Widgets.FileBrowserContentProvider class and implements its abstract members:
    • ResolveRootDirectoryAsTree - Called in order to load all subfolders of the passed as parameter folder
    • ResolveDirectory - Called in order to load all files of the passed as parameter folder
    • StoreFile - called to save an uploaded file to the storage
    • DeleteFile - called when user deletes a file
    • DeleteDirectory - called when user deletes a directory
    • CreateDirectory - called when user creates a directory
    • CanCreateDirectory - a readonly property, which value identifies if the New Directory icon will exist in the FileBrowser
    • GetFile - used in two cases: 1) to identify if a file with the same name exists in the same path when uploading a file; 2) when creating a thumbnail used to get the original image content
    • StoreBitmap - used to save a newly created bitmap to the storage
    • GetFileName - used to return the name of a file with given URL
    • GetPath - used to return the path of an item (file or directory) with given URL

    DBFileBrowserContentProvider uses a helper DataServer class, designed to handle the database operation functions.

    The file content is stored in the database and is served by the content-streamer Handler.ashx file.

    Note that the EnableFileOpen property has been disabled for this example, because opening the handler.ashx in a new window always forces the browser to download the image, instead of displaying it.

Source Code

C# VB.NET
Show code in new window Demo isolation steps
  • <%@ Page Language="vb" CodeFile="DefaultVB.aspx.vb" AutoEventWireup="true" Inherits="Telerik.Web.Examples.Editor.DBFileBrowserContentProvider.DefaultVB" %>

    <%@ Register TagPrefix="qsf" Namespace="Telerik.QuickStart" %>
    <%@ Register TagPrefix="qsf" TagName="Header" Src="~/Common/Header.ascx" %>
    <%@ Register TagPrefix="qsf" TagName="HeadTag" Src="~/Common/HeadTag.ascx" %>
    <%@ Register TagPrefix="qsf" TagName="Footer" Src="~/Common/Footer.ascx" %>
    <%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <qsf:HeadTag ID="Headtag1" runat="server" />

        <script type="text/javascript">
            //<![CDATA[
            function OnClientItemSelected(sender, args)
            {
                var pvwImage = $get("pvwImage");
                var imageSrc = args.get_item().get_url();

                if (imageSrc.match(/\.(gif|jpg)$/gi))
                {
                    pvwImage.src = imageSrc;
                    pvwImage.style.display = "";
                }
                else
                {
                    pvwImage.src = imageSrc;
                    pvwImage.style.display = "none";
                }
            }
            //]]>
        </script>

    </head>
    <body class="BODY">
        <form runat="server" id="mainForm" method="post">
        <qsf:Header ID="Header1" runat="server" NavigationLanguage="VB" />
        <telerik:RadScriptManager ID="RadScriptManager1" runat="Server" />
        <table cellspacing="4">
            <tr>
                <td rowspan="2" style="vertical-align: top;">
                    Browse to an image and click to preview.
                    <telerik:RadFileExplorer runat="server" ID="RadFileExplorer1" Width="500px" Height="300px"
                        OnClientItemSelected="OnClientItemSelected" EnableOpenFile="false">
                    </telerik:RadFileExplorer>
                </td>
                <td>
                    <fieldset style="width: 270px; height: 270px">
                        <legend>Preview</legend>
                        <img id="pvwImage" src="" alt="" style="display: none; margin: 10px; width: 250px;
                            height: 225px;" />
                    </fieldset>
                </td>
            </tr>
        </table>
        <qsf:Footer runat="server" ID="Footer1" />
        </form>
    </body>
    </html>

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