将Javascript变量传递给C＃函数aspx并从它返回到aspx页面

Question

How can I pass the variable to c# function?. Suppose that:

<script>

    var myValue;

    function setValue(idriga) {
        myValue = idriga;
    }

    function getValue() {
        return myValue;
    }

</script>

This is a script that set and get value. How can i pass the myValue value to ac# function code behind without calling aspx page and passing parameters but passing from aspx to aspx.cs and the from aspx.cs to aspx to show value returned from c# method (example search value into db and return other value?)

My function c# is:

protected string SearchUserByGuid(Guid area) {
    return (from us in contextDB.AREAS
            where us.ID_AREAS == area
            select us.USER_NAME).Single();
}

Answer 1

I'm not sure I entirely understand what you are asking for, but if I do, it's not possible .

What you can do is call a server-side method from JavaScript using AJAX. This server-side method can be a static [WebMethod] or a WebAPI method (if you use ASP.NET MVC or if you have a WebAPI Project).

For more about calling WebMethods with AJAX (and jQuery): http://deebujacob.blogspot.be/2012/01/aspnet-ajax-web-method-call-using.html

For more about Web API: http://www.asp.net/web-api/overview/getting-started-with-aspnet-web-api/tutorial-your-first-web-api

Answer 2

for passing variable to your WebMethod you can use ajax. With Jquery it it will be something like this

$.ajax({
    type: "POST",
    dataType: 'json',
    contentType: "application/json; charset=utf-8",
    url: "YourPage.aspx/SearchUserByGuid",
    data:JSON.stringify({area: 'YourValueToPass'}),
    success: function (dt) { alert(dt);}, //all Ok
    error: function () { alert('error'); } // some error
});

also your WebMethod will be public static, so change your method declaration like this

[WebMethod]
public static string SearchUserByGuid(Guid area) {
    return (from us in contextDB.AREAS
        where us.ID_AREAS == area
        select us.USER_NAME).Single();
}