How do I preserve the file selected for a file type input across a request?

Question

I have an input type="file" tag in some views. When I submit the form, if there is a validation problem and my controller action returns the same/view model but with validation errors, the file selected for the file input is cleared. How can I preserve this selected file?

Is that not the default of ASP.Net FileUpload control as well? — codingbiz, Sep 30 '12 at 14:12

danludwig · Accepted Answer · 2012-09-30T15:55:09.470

You usually get the same behavior with input type="password" tags. It is a security measure in browsers used to help protect users from malicious servers, who might try to gain access to a user's private sensitive files by pre-populating them in a file upload field.

If the file is invalid, why would you want to preserve it?

Reply to comment

If that is the case, you should be able to handle the other field validations on the client without doing a full postback. This would preserve the users' file upload entry since the page would not be re-rendered by the server after validation errors are discovered.

The file is part of a larger post, other parts of which may be invalid. — ProfK, Sep 30 '12 at 15:44

score 0 · Answer 2 · answered Sep 30 '12 at 15:35

0

AFAIK this is not possible for security reasons. You cannot set the value attribute of a file input field and this is the reason why you cannot populate it after postback.

answered Sep 30 '12 at 15:35

Darin Dimitrov

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How do I preserve the file selected for a file type input across a request?

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