Manipulating Query String Parameters in the Upload Handler

Updated on Apr 20, 2026

This help article describes how you can add query string parameters to the uploading files and how you can get this value later.

Manipulating Query String Parameters In The Upload Handler

As of Q3 2012 one can add string parameters to each uploading file in the onClientFileUploading client event by using the set_queryStringParams() method of the eventArgs parameter.

ASP.NET

<telerik:RadAsyncUpload RenderMode="Lightweight" runat="server" ID="RadAsyncUpload1" MultipleFileSelection="Automatic" OnClientFileUploading="onClientFileUploading">
</telerik:RadAsyncUpload>
	         

JavaScript

<script type="text/javascript">
    function onClientFileUploading(sender, args) {
        var obj = { first: 1, second: 2 };
        args.set_queryStringParams(obj);
    }
</script>  

These parameters can be retrieved after that in the some of the uploading processes in the Upload Handler as in the code below:

C#

protected override IAsyncUploadResult Process(UploadedFile file, HttpContext context, IAsyncUploadConfiguration configuration, string tempFileName)
{
    var queryStringParam1 = context.Request.QueryString["first"];
    var queryStringParam2 = context.Request.QueryString["second"];
    SaveToDataBase(file, configuration, context, tempFileName, queryStringParam1, queryStringParam2);
    return CreateDefaultUploadResult<UploadedFileInfo>(file);
}

VB.NET

Protected Overrides Function Process(file As UploadedFile, context As HttpContext, configuration As IAsyncUploadConfiguration, tempFileName As String) As IAsyncUploadResult
    Dim queryStringParam1 = context.Request.QueryString("first")
    Dim queryStringParam2 = context.Request.QueryString("second")
    SaveToDataBase(file, configuration, context, tempFileName, queryStringParam1, queryStringParam2)
    Return CreateDefaultUploadResult(Of UploadedFileInfo)(file)
End Function	

As of 2026 Q1 SP2, the legacy IFrame, Silverlight and Flash modules have been removed from the source code. This change improves the compatibility with modern browsers and hardens the security of the RadAsyncUpload control. The DisablePlugins property has been removed.

See Also

• Getting Started

• Multiple File Selection

• Uploaded Files Position