Event handler not initialize on initialization

Question

I have an aspx page and a code behind. The content of the page is dynamically created via XML and XSLT tContent.Controls.Add(master.ParseControl(ApplyXslt(xml, xsl_trans, xsl_args)));. Where tcontrol is the control <asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">. In the XSLT I have a telerik control

 <telerik:RadAsyncUpload RenderMode="Lightweight" ID="AsyncUpload1" runat="server" 
                                OnClientFilesUploaded="OnClientFilesUploaded" OnFileUploaded="AsyncUpload1_FileUploaded"
                                MaxFileSize="2097152" AllowedFileExtensions="jpg,png,gif,bmp"
                                AutoAddFileInputs="false" Localization-Select="Upload Image" />
        <asp:Label ID="Label1" Text="*Size limit: 2MB" runat="server" Style="font-size: 10px;"></asp:Label>

the control has an event called onFileUploaded and I have it set like this OnFileUploaded="AsyncUpload1_FileUploaded". In my Code behind I have a function defined like this

protected void AsyncUpload1_FileUploaded(object sender, FileUploadedEventArgs e)
{
    string newfilename = "logo." + e.File.GetExtension();
    string path = "/customer/" + MiscFunctions.currentCustXml+"/"+ newfilename;
    e.File.SaveAs(path);
}

I know that the onFileUploaded event is fired on post back. But for some reason it is not being called. But when I cut and paste the control directly into the content of <asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">, the eventhandler gets fired correctly. At first I thought it was becuase the generated content was being added after the controls are initialize, the genreated content was added when Page_Load was called, thus the telerik control is not initialize correctly. So I then move the code to Page_Preinit and the event is still not being called. Is there something I am missing? Or is what I am doing not possible as controls are initialize before the page life cycle?

score 0 · Answer 1 · answered Nov 03 '21 at 08:22

Using ParseControl with already defined Event-Handlers in your markup won't work.

You need to parse/add the control and then add the event handling in your code like this:

tContent.Controls.Add(master.ParseControl(ApplyXslt(xml, xsl_trans, xsl_args)));
RadAsyncUpload uploadControl = (RadAsyncUpload)tContent.FindControl("AsyncUpload1");
uploadControl.FileUploaded += AsyncUpload1_FileUploaded;

Event handler not initialize on initialization

1 Answers1