Call webservice method at server side which return data in json formate

In my previous post i have done with how to access the webservice method at client side using jQuery and how to handle the json data which is return by
webservice method.In this post i describe how we can handle the json data the webservice method at client using jQuery.

-> Take one .asmx file in your peoject for creating webservice.
-> For that i can used Northwind database and in that i take product table ( Linq To Sql Classes => .dbml file).
-> I used JavaScriptSerializer class for the convert data into json formate

public string Getjsondata()
{
string jsonstring = "";

NorthwindDataContext ObjDataContext = new NorthwindDataContext();

var product = from p in ObjDataContext.Products
select new { p.ProductID, p.ProductName };

JavaScriptSerializer js = new JavaScriptSerializer();
jsonstring = js.Serialize(product).ToString();

return jsonstring;
}


-> Now add created webservice in your project using "Add Web References".You can see in the image i have add webservice and give the name "jsonproduct".

-> For getting json data at server side we can create one "JsonProduct" class

class JsonProduct
{
public string productid { get; set; }
public string productname { get; set; }

}


-> After this you can access the webservice method in .cs file using webservice class in my case i have "getproduct" class and also i am adding one
dropdownlist in .aspx page

// Web Service Class and create the the object of that class
getproduct ObjProduct = new getproduct();

// Using created object i can call the webservice method and take the json data into string variable
string jsonstring = ObjProduct.HelloWorld();

// After that i can used JavaScriptSerializer class for Deserialize json string and store the data into IList
IList<JsonProduct> persons = new JavaScriptSerializer().Deserialize<IList<JsonProduct>>(jsonstring);

// Bind IList object to dropdownlist datasource
ddlProduct.DataSource = persons;
ddlProduct.DataTextField = "productname";
ddlProduct.DataValueField = "productid";
ddlProduct.DataBind();


Call the webservice at client side using jquery

In my previous post i have done with how to access the webservice method at client side using AjaxcontrolToolKit.

Initial Steps
--------------
-> Add one .asmx [In my case i add Testservice.asmx] file in your peoject for creating webservice.
-> Then add "ScriptService" attribute see the Fig.-1. Using "ScriptService" we can access the
webserivce method in the javascript.
-> After that add 2 different web method in the webservice see the Fig.- 1.
-> First method don't take any parameter and return string and second method take one
parameter and return string.

-> Add the jQuery script

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script>

-> Here i have take two different example in first i don't pass any parameter and in the second
example i pass one parameter and get the results

EXample 1 : Call the webservice method without passing any parameter

-> Add one button and one div tag for display result

<input type="button" name="btnCall" value="Call Webservice" id="btnCall" />
<div id="output">
</div>

-> Now add some javascript bwtween two script tag for calling webservice method...

$(function () {
$('#btnCall').click(getData)
});

function getData() {
$.ajax(
{
type: "POST",
url: "http://yourservername/AjaxExample/WebService/Testservice.asmx/HelloWorld",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",

success: function (response, status) {
//alert(response.d);
$('#output').empty();
$('#output').append(response.d);

},
failure: function (msg) {
alert(msg);
}
}
);
}

Here you can see that i have not pass anything in data attribute and two other
function success and failure which is inbulit function for the jQuery.

Example 2 : Call the webservice method which take one string parameter

-> For that you can add following html code in your file.

<input type="text" name="txtData" value="Test string is come." id="txtData" />
<input type="button" name="btnCall1" value="Get string From webservice" id="btnCall1" />
<br />
<div id="output">
</div>

-> After that you can add following javascript function between script tag

$(function () {
$('#btnCall1').click(getstring)
});

function getstring() {
$.ajax(
{
type: "POST",
url: "http://yourserver/AjaxExample/WebService/Testservice.asmx/GetString",
data: "{ strData: '" + $('#txtData').val() + "'}",
contentType: "application/json; charset=utf-8",
dataType: "json",

success: function (response, status) {
//alert(response.d);
$('#output').empty();
$('#output').append(response.d);

},
failure: function (msg) {
alert(msg);
}
}
);
}

Here you can see that i take the data from the textbox and pass that data to webservice method and get the result

Above two webmethod is simple which return string data but what if webmethod return json data.

EXample 3 : Call the webservice method which return string data but in the form of json.

-> For that i can used Northwind database and in that i take product table ( Linq To Sql Classes => .dbml file).

-> I used JavaScriptSerializer class for the convert data into json formate

public string Getjsondata()
{
string jsonstring = "";

NorthwindDataContext ObjDataContext = new NorthwindDataContext();

var product = from p in ObjDataContext.Products
select new { p.ProductID, p.ProductName };

JavaScriptSerializer js = new JavaScriptSerializer();
jsonstring = js.Serialize(product).ToString();

return jsonstring;
}

-> Now add html button in your page

<input type="button" name="btnCallJson" value="Retrun Json Data" id="btnCallJson" />
<br />
<div id="output">
</div>

-> After that you can add this javascript function in the script tag

$(function () {
$('#btnCallJson').click(getjsondata)
});

function getjsondata() {
$.ajax(
{
type: "POST",
url: "http://yourserver/AjaxExample/WebService/Testservice.asmx/Getjsondata",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",

success: function (response, status) {
var myObjects = eval('(' + response.d + ')');
//alert(myObjects.length);
$('#output').empty();
$.each(myObjects, function (index, myObject) {
$('#output').append('<p><strong>(' + myObject.ProductID + ')' +
myObject.ProductName + '</strong>');
});
},
failure: function (msg) {
alert(msg);
}
}
);
}

Here i take used eval for json parse and take jQuery each syntax for taking data from json and display that data into div tag.