Persist files after PostbackTrigger Help

[Maxi]

Hello, i'm using RadAsyncUpload to send files to server. i am setting a postbacktrigger to button "save". The problem exists when a something goes wrong at server side.
for example: if some textbox has the incorrect format a valitonsummary displays the error message, but the uploaded files disappear, its like the control reset.

anyone knows how to stop the reset after PostbackTrigger?

thanks

[Shinu]

Hello,

Check the following demo.
AsyncUpload / Persist Uploaded Files

-Shinu.

[Maxi]

Thnaks, but the control 'RadAsyncUpload' is still losing the file after PostBackTrigger. 

[Brad]

I think what is being asked here is when the RadAsyncUpload control is being used on a page that has other controls which are validating (server side), and the page level validation fails (Page.IsValid = false), the upload control resets.

Is there any way to persist the upload control across a postback when the page does not validate?

[Hristo Valyavicharski]

Hi,

Unfortunately at the moment it is not possible to validate the AsyncUpload on the server with the ASP.NET Validators. There are two things, which you can do:

• Validate AsyncUpload on the client with the ASP.NET Custom Validator
• Or to use Custom Handler and perform server side validation in the Process() method.

Regards,
Hristo Valyavicharski
Telerik

[Cheah]

any example?

[Zubair]

anyone solve this problem in 2020 ? :P

Please share how to Validate AsyncUpload on the client with the ASP.NET Custom Validator

[Peter Milchev]

Hello,

For the client-side validation to work properly, the custom validator must have its client-side functionality enabled:

<telerik:RadAsyncUpload ID="RadAsyncUpload1"
    runat="server"  >
</telerik:RadAsyncUpload>
<asp:CustomValidator ID="cvUploadFiles"
    EnableClientScript="true"
    ClientValidationFunction="validateUpload"
    runat="server" ValidationGroup="UploadErrors"
    ErrorMessage="You must select one file to upload."
    Display="None"></asp:CustomValidator>

Then, the validation function must get a proper reference to the async upload control or it will throw errors (you can read more on the subject below):

• https://docs.telerik.com/devtools/aspnet-ajax/general-information/get-client-side-reference

• function validateUpload(sender, args) {
      var uploadobj = $find("<%=RadAsyncUpload1.ClientID%>");
      args.IsValid = uploadobj.getUploadedFiles().length != 0;
  }

 

Also, if .NET 4.5+ is used, the following web.config entry should be set:

• http://stackoverflow.com/questions/16660900/webforms-unobtrusivevalidationmode-requires-a-scriptresourcemapping-for-jquery

• <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />

  
  

Regards,
Peter Milchev
Progress Telerik