I have AsyncUpload on my page, and I have a very complex validation on the page - this is where server-side validation is used.
When the user does not fill in all mandatory fields / fulfil the submission criteria, error messages will be shown on the page.
At this time, the AsyncUpload control do not keep the earlier uploaded document anymore.
I believe it was because the PostbackTriggers set to btnSubmit, and the client state is lost.
Is there anyway for me to preserve the AsyncUpload client state in the server-side?
For example, in the below code, as soon as I have detected that the "IsIdeaValid" is false, I will preserve the AsyncUpload client state.
protected void btnSubmit_Click(object sender, EventArgs e)
ErrorMessage = "";