how to call an ASP NET c method using javascript

Question

Does anyone know how to call a server-side c  method using javascript  What i need to do is to stop imports if Cancel is chosen or to continue importing if ok is chosen  I am using visual studio 2010 and c  as my programming lanaguage  This is my code   private void AlertWithConfirmation                                      Response Write            lt script type   text javascript   gt                       if  window confirm  Import is currently in progress  Do you want to continue with importation  If yes choose OK  If no choose CANCEL                               window alert  Imports have been cancelled                            else                          window alert  Imports are still in progress                                              lt  script gt

User · Answer

You will need to do an Ajax call I suspect. Here is an example of an Ajax called made by jQuery to get you started. The Code logs in a user to my system but returns a bool as to whether it was successful or not. Note the ScriptMethod and WebMethod attributes on the code behind method.

in markup:

 var $Username = $("#txtUsername").val();
            var $Password = $("#txtPassword").val();

            //Call the approve method on the code behind
            $.ajax({
                type: "POST",
                url: "Pages/Mobile/Login.aspx/LoginUser",
                data: "{'Username':'" + $Username + "', 'Password':'" + $Password + "' }", //Pass the parameter names and values
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                async: true,
                error: function (jqXHR, textStatus, errorThrown) {
                    alert("Error- Status: " + textStatus + " jqXHR Status: " + jqXHR.status + " jqXHR Response Text:" + jqXHR.responseText) },
                success: function (msg) {
                    if (msg.d == true) {
                        window.location.href = "Pages/Mobile/Basic/Index.aspx";
                    }
                    else {
                        //show error
                        alert('login failed');
                    }
                }
            });

In Code Behind:

/// <summary>
/// Logs in the user
/// </summary>
/// <param name="Username">The username</param>
/// <param name="Password">The password</param>
/// <returns>true if login successful</returns>
[WebMethod, ScriptMethod]
public static bool LoginUser( string Username, string Password )
{
    try
    {
        StaticStore.CurrentUser = new User( Username, Password );

        //check the login details were correct
        if ( StaticStore.CurrentUser.IsAuthentiacted )
        {
            //change the status to logged in
            StaticStore.CurrentUser.LoginStatus = Objects.Enums.LoginStatus.LoggedIn;

            //Store the user ID in the list of active users
            ( HttpContext.Current.Application[ SessionKeys.ActiveUsers ] as Dictionary<string, int> )[ HttpContext.Current.Session.SessionID ] = StaticStore.CurrentUser.UserID;

            return true;
        }
        else
        {
            return false;
        }
    }
    catch ( Exception ex )
    {
        return false;
    }
}

User · Answer

PageMethod an easier and faster approach for Asp Net AJAX We can easily improve user experience and performance of web applications by unleashing the power of AJAX  One of the best things which I like in AJAX is PageMethod    PageMethod is a way through which we can expose server side page s method in java script  This brings so many opportunities we can perform lots of operations without using slow and annoying post backs   In this post I am showing the basic use of ScriptManager and PageMethod  In this example I am creating a User Registration form  in which user can register against his email address and password  Here is the markup of the page which I am going to develop    lt body gt       lt form id  form1  runat  server  gt       lt div gt           lt fieldset style  width  200px   gt               lt asp Label ID  lblEmailAddress  runat  server  Text  Email Address  gt  lt  asp Label gt               lt asp TextBox ID  txtEmail  runat  server  gt  lt  asp TextBox gt               lt asp Label ID  lblPassword  runat  server  Text  Password  gt  lt  asp Label gt               lt asp TextBox ID  txtPassword  runat  server  gt  lt  asp TextBox gt           lt  fieldset gt           lt div gt           lt  div gt           lt asp Button ID  btnCreateAccount  runat  server  Text  Signup     gt       lt  div gt       lt  form gt   lt  body gt   lt  html gt    To setup page method  first you have to drag a script manager on your page    lt asp ScriptManager ID  ScriptManager1  runat  server  EnablePageMethods  true  gt   lt  asp ScriptManager gt    Also notice that I have changed EnablePageMethods  true   This will tell ScriptManager that I am going to call PageMethods from client side    Now next step is to create a Server Side function  Here is the function which I created  this function validates user s input    WebMethod  public static string RegisterUser string email  string password        string result    Congratulations    your account has been created        if  email Length    0   Zero length check               result    Email Address cannot be blank             else if   email Contains          email Contains         some other basic checks               result    Not a valid email address             else if   email Contains          email Contains         some other basic checks               result    Not a valid email address              else if  password Length    0                result    Password cannot be blank             else if  password Length  lt  5                result    Password cannot be less than 5 chars              return result      To tell script manager that this method is accessible through javascript we need to ensure two things  First  This method should be  public static   Second  There should be a  WebMethod  tag above method as written in above code   Now I have created server side function which creates account  Now we have to call it from client side  Here is how we can call that function from client side    lt script type  text javascript  gt      function Signup             var email   document getElementById   lt   txtEmail ClientID   gt    value          var password   document getElementById   lt   txtPassword ClientID   gt    value           PageMethods RegisterUser email  password  onSucess  onError            function onSucess result                alert result                      function onError result                alert  Cannot process your request at the moment  please try later                      lt  script gt    To call my server side method Register user  ScriptManager generates a proxy function which is available in PageMethods  My server side function has two paramaters i e  email and password  after that parameters we have to give two more function names which will be run if method is successfully executed  first parameter i e  onSucess  or method is failed  second parameter i e  result    Now every thing seems ready  and now I have added OnClientClick  Signup   return false   on my Signup button  So here complete code of my aspx page     lt  DOCTYPE html PUBLIC  -  W3C  DTD XHTML 1 0 Transitional  EN   http   www w3 org TR xhtml1 DTD xhtml1-transitional dtd  gt   lt html xmlns  http   www w3 org 1999 xhtml  gt   lt head runat  server  gt       lt title gt  lt  title gt   lt  head gt   lt body gt       lt form id  form1  runat  server  gt       lt div gt           lt asp ScriptManager ID  ScriptManager1  runat  server  EnablePageMethods  true  gt           lt  asp ScriptManager gt           lt fieldset style  width  200px   gt               lt asp Label ID  lblEmailAddress  runat  server  Text  Email Address  gt  lt  asp Label gt               lt asp TextBox ID  txtEmail  runat  server  gt  lt  asp TextBox gt               lt asp Label ID  lblPassword  runat  server  Text  Password  gt  lt  asp Label gt               lt asp TextBox ID  txtPassword  runat  server  gt  lt  asp TextBox gt           lt  fieldset gt           lt div gt           lt  div gt           lt asp Button ID  btnCreateAccount  runat  server  Text  Signup  OnClientClick  Signup   return false     gt       lt  div gt       lt  form gt   lt  body gt   lt  html gt    lt script type  text javascript  gt      function Signup             var email   document getElementById   lt   txtEmail ClientID   gt    value          var password   document getElementById   lt   txtPassword ClientID   gt    value           PageMethods RegisterUser email  password  onSucess  onError            function onSucess result                alert result                      function onError result                alert  Cannot process your request at the moment  please try later                      lt  script gt

User · Answer

There are several options  You can use the WebMethod attribute  for your purpose

User · Answer

I m going to go right ahead and offer a solution using jQuery  which means you will need to import the library if you haven t already     Import the jQuery library in your page mark-up    lt script src  https   ajax googleapis com ajax libs jquery 1 4 4 jquery min js  type  text javascript  gt  lt  script gt    Then create another   js script file  I call mine ExecutePageMethod  since that is the only method it is going to expose  and import it    lt script type  text javascript  src   ExecutePageMethod js   gt  lt  script gt    Within the newly added file  add the following code  I remember pulling this from elsewhere  so someone else deserves credit for it really    function ExecutePageMethod page  fn  paramArray  successFn  errorFn        var paramList           if  paramArray length  gt  0            for  var i   0  i  lt  paramArray length  i    2                if  paramList length  gt  0  paramList                     paramList          paramArray i            paramArray i   1                             paramList         paramList              ajax           type   POST           url  page         fn          contentType   application json  charset utf-8           data  paramList          dataType   json           success  successFn          error  errorFn             You will then need to augment your  NET page method with the appropriate attributes  as such    WebMethod   ScriptMethod ResponseFormat   ResponseFormat Json   public static string MyMethod         return  Yay        Now  within your page mark-up  within a script block or from another script file  you can call the method  like so   ExecutePageMethod  PageName aspx    MyMethod       OnSuccess  OnFailure     Obviously you will need to implement the OnSuccess and OnFailure methods   To consume the results  say in the OnSuccess method  you can use the parseJSON method  which  if the results become more complex  in the case or returning an array of types  for instance  this method will parse it into objects   function OnSuccess result        var parsedResult   jQuery parseJSON result d       This ExecutePageMethod code is particularly useful since it it reusable  so rather than having to manage an   ajax call for each page method you might want to execute  you just need to pass the page  method name and arguments to this method

User · Answer

The Jayrock RPC library is a great tool for doing this in a nice familliar way for C  developers  It allows you to create a  NET class with the methods you require  and add this class as a script  in a roundabout way  to your page  You can then create a js object of your type and call methods as you would any other object   It essentially hides away ajax implementation and presents RPC in a familliar format  Mind you the best option really is to use ASP NET MVC and use jQuery ajax calls to action methods - much more concise and less messing about

[c#] how to call an ASP.NET c# method using javascript

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