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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(
"<script type=\"text/javascript\">" +
"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');" +
"}" +
"</script>");
}
704
ASP.NET is part of the . NET framework allowing you to write web applications using any CLS compliant language such as C#, VB.NET, F#, ... What you are referring to original asp language is called Classic ASP and it is not a language.
The WebMethod attribute is added to each method we want to expose as a Web Service. ASP.NET makes it possible to map traditional methods to Web Service operations through the System. Web. Services. WebMethod attribute and it supports a number of properties that control the behavior of the methods.
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:
<body> <form id="form1" runat="server"> <div> <fieldset style="width: 200px;"> <asp:Label ID="lblEmailAddress" runat="server" Text="Email Address"></asp:Label> <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox> <asp:Label ID="lblPassword" runat="server" Text="Password"></asp:Label> <asp:TextBox ID="txtPassword" runat="server"></asp:TextBox> </fieldset> <div> </div> <asp:Button ID="btnCreateAccount" runat="server" Text="Signup" /> </div> </form> </body> </html> To setup page method, first you have to drag a script manager on your page.
<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true"> </asp:ScriptManager> 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 < 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:
<script type="text/javascript"> function Signup() { var email = document.getElementById('<%=txtEmail.ClientID %>').value; var password = document.getElementById('<%=txtPassword.ClientID %>').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.'); } } </script> 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 :
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <div> <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true"> </asp:ScriptManager> <fieldset style="width: 200px;"> <asp:Label ID="lblEmailAddress" runat="server" Text="Email Address"></asp:Label> <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox> <asp:Label ID="lblPassword" runat="server" Text="Password"></asp:Label> <asp:TextBox ID="txtPassword" runat="server"></asp:TextBox> </fieldset> <div> </div> <asp:Button ID="btnCreateAccount" runat="server" Text="Signup" OnClientClick="Signup();return false;" /> </div> </form> </body> </html> <script type="text/javascript"> function Signup() { var email = document.getElementById('<%=txtEmail.ClientID %>').value; var password = document.getElementById('<%=txtPassword.ClientID %>').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.'); } } </script> 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;
}
}
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:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js" type="text/javascript"></script>
Then create another *.js script file (I call mine ExecutePageMethod, since that is the only method it is going to expose) and import it:
<script type="text/javascript" src="/ExecutePageMethod.js" ></script>
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 > 0) {
for (var i = 0; i < paramArray.length; i += 2) {
if (paramList.length > 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.
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