How to download file using handler

Here is a detailed description on How to download file using handler. Also some tips on RadUpload custom validation.

You can use a generic handler to download files from server, it has the following advantages:

1. You can have download statistics.
2. You can track downloads.
3. You can implement download protection by putting extra authentication.
4 Download can be disallowed if required.

Lets say you have a RadUpload control on your page.

<telerik:RadUpload ID="rup_AttachedFiles" runat="server" ControlObjectsVisibility="RemoveButtons, AddButton" />

And you want to validate the files on the client side which are being uploaded,
so add a custom validator:

<asp:customvalidator id="CustomValidator1" runat="server" validationgroup="frmInquiry"
    enabled="true" clientvalidationfunction="ValidateFileNames" errormessage="Please Upload a file or same file is being uploaded twice"
    text="*" display="None" />

Now you write the Client Validation Function for your custom validator:

<script type="text/javascript">
    function ValidateFileNames(Source, args) {
        var FilesValid = true;
        var AttachedFiles = new Array();
        var radUpload = $find('<%= rup_AttachedFiles.ClientID %>');
        var fileInputs = radUpload.getFileInputs();
        if ((fileInputs.length == 1) && (fileInputs[0].value == "")) {
            FilesValid = false;
        else {
            var duplicateFieldFlag = false;
            for (var i = 0; i < fileInputs.length; i++) {
                var fileName = fileInputs[i].value.substring(fileInputs[i].value.lastIndexOf("\\") + 1, fileInputs[i].value.length);
                for (var j = 0; j < AttachedFiles.length; j++) {
                    if (fileName == AttachedFiles[j]) {
                        duplicateFieldFlag = true;
                if (duplicateFieldFlag) {
                    FilesValid = false;
                if (fileInputs[i].value.length != 0) {
                    AttachedFiles[AttachedFiles.length] = fileName;
        args.IsValid = FilesValid;


I am not going into detail of how to upload it using RadUpload control. Its time to put a repeater control to show a list of already uploaded files from the server. Again I will not explain how to get the uploaded files information from DB and bind it to the repeater.

<asp:repeater id="rpAttach" runat="server" onitemdatabound="rpAttach_onItemDataBound">
       <table id="tbl1" cellpadding="0" cellspacing="0" border="0" width="100%">
           <asp:Label runat="server" ID="lblAttachement" Text="File Name" />
       <td >
        <asp:LinkButton ID="lnkFileName" runat="server" ></asp:LinkButton>
                <hr />

Now you have to define the event handler rpAttach_onItemDataBound for the event OnItemDataBound. Where you will bind the file name link to a javascript function. Which will show a Disclaimer text before downloading:

protected void rpAttach_onItemDataBound(object
    sender, RepeaterItemEventArgs e) 
        if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item) 
            LinkButton aLinkFileName = (LinkButton)e.Item.FindControl("lnkFileName");
            Files sFile = ((Files)e.Item.DataItem); aLinkFileName.Text = sFile.FileName; aLinkFileName.Attributes.Add("OnClick","OpenDisclaimer('" + HttpUtility.UrlEncode(strBasePath) + "','" + HttpUtility.UrlEncode(sFile.FileName)+ "','" + ConfigurationManager.AppSettings["DisclaimerText"] + "')"); 

Now put the disclaimer text in the web config file

<add key="DisclaimerText" value="The attachment contains confidential and proprietary information. You have abide by copyright laws. blah blah blah " />

Now we have to define the function OpenDisclaimer

<script type="text/javascript">
        function OpenDisclaimer(strFilePath, strFileName, strText) {
            strURL = 'Handlers/GetFile.ashx?FullPath=' + strFilePath + '&FileName=' + strFileName;
            var answer = confirm("Disclaimer: " + strText);
            if (answer) {
                window.location.href = strURL;
                return true;
            return false;

Now is the time to add the GetFile handler to your project. Below is the code for it. It recognizes the file type and puts the contents of file type into chunks by chunks to client. // Handlers/GetFile.ashx

<%@  WebHandler Language="C#" Class="GetFile" %>

    using System; 
    using System.Collections; 
    using System.Data; 
    using System.Linq; 
    using System.Web; 
    using System.Web.Services; 
    using System.Web.Services.Protocols; 
    using System.Xml.Linq; 
    using System.IO; 
    using System.Web.SessionState; 
    using System.Configuration;

    [WebService(Namespace = "")] 
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] 

    public class GetFile : IHttpHandler, IReadOnlySessionState
        public void ProcessRequest(HttpContext context) 
                string FilePath = context.Request.Params["FullPath"];
                string filename = context.Request.Params["FileName"]; 

                FilePath = HttpUtility.UrlDecode(FilePath);
                string fullPath = "\\FileServername\FolderName\" + FilePath + filename; 

                // "\\FileServername\FolderName\" you can keep this path in web config string extension = System.IO.Path.GetExtension(filename);

                if (extension == null) 
                    extension = ""; 
                extension = extension.Replace(".", "");

                string contentDisposition; 

                if (context.Request.Browser.Browser == "IE" && (context.Request.Browser.Version == "7.0" || context.Request.Browser.Version == "8.0")) 
                    contentDisposition = "attachment; filename=" + Uri.EscapeDataString(filename); 
                else if (context.Request.Browser.Browser == "Safari") 
                    contentDisposition = "attachment; filename=" + filename; 
                    contentDisposition= "attachment; filename*=UTF-8''" + Uri.EscapeDataString(filename); 

                context.Response.ContentType = "Application/" + extension;

                System.IO.BinaryReader reader = new System.IO.BinaryReader(new System.IO.FileStream(fullPath,System.IO.FileMode.Open)); 

                //Sent the data in chunks of x byte int ChunkSize = 10000;
                byte[] buffer = new byte[ChunkSize]; 
                int idx = 0; 
                long size = 0; 

                //Write the file chunk by chunk. 

                while ((size = reader.Read(buffer, 0, ChunkSize)) == ChunkSize)
                    idx += ChunkSize; 


                //Write the remaining bytes 
                if (size > 0) 
                    byte[] remaining = new byte[size]; Array.Copy(buffer, 0, remaining, 0, size); 
                context.Response.ContentType= "Application/html"; 
                context.Response.StatusCode = 404; 
                context.Response.StatusDescription = "File not found"; 


Compare date and time using RadDateTimePicker

After searching a lot I found the solution to compare date and time using RadDateTimePicker because it was not fulfilling my requirements. So if you are working with Telerik RadDateTimePicker and you want to compare date and time using RadDateTimePicker then you can use the following code:

Lets say you have following two RadDateTimePicker controls on your page for start date and end date:

This one

<telerik:RadDateTimePicker ID=”dpStartDateTime” runat=”server”>
<TimeView ID=”TimeView1″ Interval=”00:30:00″ runat=”server” StartTime=”07:30:00″>
<DateInput ID=”DateInput1″ runat=”server”>
<ClientEvents OnLoad=”onLoadRadTimePicker1″></ClientEvents>

and the other one

<telerik:RadDateTimePicker ID=”dpEndDateTime” runat=”server”>
<TimeView ID=”TimeView2″ Interval=”00:30:00″ runat=”server” StartTime=”07:30:00″>
<DateInput ID=”DateInput2″ runat=”server”>
<ClientEvents OnLoad=”onLoadRadTimePicker2″></ClientEvents>

Your RadDateTimePicker may have different properties for TimeView according to what you want to display in time picker.

Now you have to put the CustomValidator control on your page in order to do the validation for start and end date.

<asp:CustomValidator runat=”server” ID=”CustomValidator1″ Text=”*” Display=”dynamic”
EnableClientScript=”true” ClientValidationFunction=”compare” />

You can set the ValidateEmptyText=”false” in the above tag if you do not want to compare the empty text.

Also you can set the ValidationGroup=”YourValidationGroupName” in the above tag if you want to do the validation for specific group using specific button click.

Now you have to write your CustomValidator ClientValidationFunction which will do the validation and date time comparison.

<script type=”text/javascript”>

var RadTimePicker1;
var RadTimePicker2;

function compare(sender, args) {
var Date1 = new Date(RadTimePicker1.get_selectedDate());
var Date2 = new Date(RadTimePicker2.get_selectedDate());

args.IsValid = true;
if ((Date2 – Date1) <= 0) {
alert(‘End date time must be greater than start date time’);
args.IsValid = false;

function onLoadRadTimePicker1(sender, args) {
RadTimePicker1 = sender;

function onLoadRadTimePicker2(sender, args) {
RadTimePicker2 = sender;