Populate a Razor Section From a Partial

Partial views cannot participate in their parent views' sections.

The way I dealt with this is to write a couple extension methods to the HtmlHelper class. That allows partials views to say that they require a script, and then in the layout view that writes the tag I call to my helper method to emit the required scripts

Here are the helper methods:

public static string RequireScript(this HtmlHelper html, string path, int priority = 1)
{
    var requiredScripts = HttpContext.Current.Items["RequiredScripts"] as List<ResourceInclude>;
    if (requiredScripts == null) HttpContext.Current.Items["RequiredScripts"] = requiredScripts = new List<ResourceInclude>();
    if (!requiredScripts.Any(i => i.Path == path)) requiredScripts.Add(new ResourceInclude() { Path = path, Priority = priority });
    return null;
}

public static HtmlString EmitRequiredScripts(this HtmlHelper html)
{
    var requiredScripts = HttpContext.Current.Items["RequiredScripts"] as List<ResourceInclude>;
    if (requiredScripts == null) return null;
    StringBuilder sb = new StringBuilder();
    foreach (var item in requiredScripts.OrderByDescending(i => i.Priority))
    {
        sb.AppendFormat("<script src=\"{0}\" type=\"text/javascript\"></script>\n", item.Path);
    }
    return new HtmlString(sb.ToString());
}
public class ResourceInclude
{
    public string Path { get; set; }
    public int Priority { get; set; }
}

Once you have that in place your partial view just needs to call @Html.RequireScript("/Path/To/Script").

And in the layout view's head section you call @Html.EmitRequiredScripts().

An added bonus of this is that it allows you to weed out duplicate script requests. If you have multiple views/partial views that need a given script you can safely assume that you will only output it once