How to prevent files to upload if exceed specific

问题:

In MVC, I need to make restriction to upload file limit size should not exceed 5 MB.

Here, i need to validate and restrict at client side only if exceed 5MB size limit.

I able to achieve using ajax file uploader but, it support IE 10 and above but, I delicately need to provide support for IE 9 and above.

Please guide how i can make the validation at client side or any alternative solution ?

回答1:

To check when a file is uploaded, you could add in a web.config key:

<add key="maxRequestLength" value="5242880"/> <!-- in Bytes -->

then when you post a file in your code where file is the HttpPostedFileBase:

if (file.ContentLength > 0 && file.ContentLength < Convert.ToDouble(WebConfigurationManager.AppSettings["maxRequestLength"]) {
    //do stuff
}
else {
    //return error to view
}

In addition, you can enforce a site-wide limit in Web.Config via the following:

<system.web>
    <httpRuntime maxRequestLength="5120" /> <!-- in Kb -->
    ...

The top variable just allows you to nicely manage your on screen error though.

回答2:

    Check java script/ JQuery validation:
    $('#file_select')[0].files[0], file.size

    check test code here : [Click Here][1]

      [1]: http://jsfiddle.net/rq8nA/



    $("input:file").change(function () {
           if ($(this).val() !== "") {
            var file = $('#file_select')[0].files[0];
               if(file.size > 5000) {
                $('#err').html("Could not upload more than 5kb");           
               }
           }
    });
    <input type="file" name="file" id="file_select" />
    <span id="err"></span>