Dynamically change the PostbackTriggers collection of the AsyncUpload

RELATED TO:

AUTHOR: Peter Milchev

DATE POSTED: November 17, 2017

How To:


Change the PostbackTriggers collection dynamically. For example, when the validation on the server passes, the control that fired the postback should become a PostbackTrigger for the AsyncUpload 

SOLUTIONS


The PostbackTriggers collection can be modified in the Page_Init event of the page lifecycle. That would allow adding certain controls to the PostbackTriggers collection based on hidden field values or some other custom logic.

Here is an example that adds the button that triggered a postback as a PostbackTrigger if the value of a hidden field is equal to "fixTriggers":

Markup: 

<asp:HiddenField runat="server" ID="shouldSave" />


JavaScript:

function updateHiddenField() {
        var hidden = document.getElementById("<%= shouldSave.UniqueID %>");
        hidden.value = "fixTriggers";
}


CodeBehind:

protected void Page_Init(object sender, EventArgs e)
{
    if (Request[shouldSave.UniqueID] != null && Request[shouldSave.UniqueID].ToString() == "fixTriggers")
    {
        RadAsyncUpload1.PostbackTriggers = new string[] { "RadButton1" };
    }
}
      
protected void RadAsyncUpload1_FileUploaded(object sender, FileUploadedEventArgs e)
{
    shouldSave.Value = "";
}

 

Here are some resources that can help to get the ID of the control that triggered the postback:


More Resources

  • Forums

    Find answers to thousands of questions or reach out to our active community.

  • Demos

    Browse 1,200+ demos with source code covering basic and advanced scenarios.

  • Sample Applications

    Learn how to integrate the controls in real-world examples.

  • Feedback Portal

    Vote and follow the features you want to see added to Telerik UI for ASP.NET AJAX.

  • User Voice

    Get answers directly from the people who build the product.

  • Documentation

    Benefit from detailed help articles and API references for all controls.

  • Knowledge Base

    Learn how to achieve common scenarios from a multitude of tutorials and working examples.

  • Code Library

    Browse sample projects submitted by Telerik staff and community members.

  • Blog

    Stay up-to-date with the latest functionality, how-to articles and industry trends.

  • Release History

    Up-to-date release notes for all new features and improvements.