force browsers to get latest js and css files in asp.net application

Your solution works. It is quite popular in fact.

Even Stack Overflow uses a similar method:

<link rel="stylesheet" href="http://sstatic.net/so/all.css?v=6184"> 

Where v=6184 is probably the SVN revision number.

ASP.NET MVC will handle this for you if you use bundles for your JS/CSS. It will automatically append a version number in the form of a GUID to your bundles and only update this GUID when the bundle is updated (aka any of the source files have changes).

This also helps if you have a ton of JS/CSS files as it can greatly improve content load times!

See Here

I solved this by tacking a last modified timestamp as a query parameter to the scripts.

I did this with an extension method, and using it in my CSHTML files. Note: this implementation caches the timestamp for 1 minute so we don't thrash the disk quite so much.

Here is the extension method:

public static class JavascriptExtension {
    public static MvcHtmlString IncludeVersionedJs(this HtmlHelper helper, string filename) {
        string version = GetVersion(helper, filename);
        return MvcHtmlString.Create("<script type='text/javascript' src='" + filename + version + "'></script>");
    }

    private static string GetVersion(this HtmlHelper helper, string filename)
    {
        var context = helper.ViewContext.RequestContext.HttpContext;

        if (context.Cache[filename] == null)
        {
            var physicalPath = context.Server.MapPath(filename);
            var version = $"?v={new System.IO.FileInfo(physicalPath).LastWriteTime.ToString("MMddHHmmss")}";
            context.Cache.Add(filename, version, null,
              DateTime.Now.AddMinutes(5), TimeSpan.Zero,
              CacheItemPriority.Normal, null);
            return version;
        }
        else
        {
            return context.Cache[filename] as string;
        }
    }
}

And then in the CSHTML page:

 @Html.IncludeVersionedJs("/MyJavascriptFile.js")

In the rendered HTML, this appears as:

 <script type='text/javascript' src='/MyJavascriptFile.js?20111129120000'></script>

In ASP.NET Core (MVC 6) this works out of the box via the asp-append-version tag helper:

<script src="scripts/myjavascript.js" asp-append-version="true"></script>
<link href="styles/mystyle.css rel="stylesheet" asp-append-version="true" />