The name of the form field that can contain the post-back ID with which all subsequent files in the request should be associated.
The name of the form field that can contain the post-back ID with which all subsequent files in the request should be associated.
For example, if PostBackIDFieldName is "NeatUpload_PostBackID", then if a request contains a form field named "NeatUpload_PostBackID" with a value of "123ABC", all subsequent files in the request will be assocated with post-back ID "123ABC". The post-back ID must not contain the character "-".