Call asp.net function with out button click from java script directly with out page refresh

Question

I am trying to check if the specific value exist in the data base that is working perfect but what i want is

I want to call a C# function from JavaScript
as now in my code after JavaScript clicks button it response but page also refreshes i don't Want page refresh to be happen

better way to call C# function with out using button from javascript

protected void Check_exam_id(object sender, EventArgs e)
{         
    string DDSelected_Class = DD_class.SelectedValue;// store it in some variable;
    string DD__Method = DD_Method.SelectedValue;// store it in some variable;

    if (DD__Method == "THEORY")

        {
    using (MySqlConnection myConnection = new MySqlConnection(constr))
    {
        string oString = "Select * from score_master WHERE Class=@DDSelected_Class ";
        MySqlCommand oCmd = new MySqlCommand(oString, myConnection);
        oCmd.Parameters.AddWithValue("@DDSelected_Class", DDSelected_Class);

        myConnection.Open();
        using (MySqlDataReader oReader = oCmd.ExecuteReader())
        {

            if (oReader == null || !oReader.HasRows)
            {
                ScriptManager.RegisterStartupScript(this, typeof(Page), "alert", "alert('No Student Found')", true);


            }
            else
            {
                ScriptManager.RegisterStartupScript(this, typeof(Page), "alert2", "alert('Exist')", true);

                myConnection.Close();
            }
        }

    }


    }

}

asp button

 <asp:Button runat="server" id="Check_examid"  AutoPostback = "false" onclick='Check_exam_id'   style="  display:none;   float: right;    width: 22%;    height: 41px;    text-align: center;    background: #EAEAEA;    border: none;    border-color: #EAEAEA;    margin-top: 2%;" Text="Submit"></asp:Button>

Javascript

    document.getElementById("BodyHolder_Check_examid").click()

@RahulSingh am not sure about it if u give me an example that would be more helpfull — Shaik
– Shaik, Commented Dec 22, 2015 at 10:06

Rahul Singh · Accepted Answer · 2015-12-22 10:32:43Z

2

As mentioned in the comment, you can easily do it with jquery ajax. For this you will have to define a WebMethod something like this:-

Please include using System.Web.Services;.

[WebMethod]
public static bool Check_exam_id(string className, string MethodName)
{
    bool examIdExist = false;
    if (DD__Method == "THEORY")
    {
        \\Your logic here
    }
    \\Based on DB operation return value
    examIdExist 
}

Finally call it from your client side like this:-

$("#Check_examid").click(function (e) {
    e.preventDefault(); //To avoid postback
    //Get these values from dropdwon
    var className = $("#DD_class").val();
    var methodName = $("#DD_Method").val();
    var data = { "className": className , "MethodName": methodName };  
    $.ajax({
        type: "POST",
        dataType: "json",
        contentType: "application/json; charset=utf-8",
        url: "Default.aspx/Check_exam_id",
        data: JSON.stringify(data),
        success: function (response) {
            if(response.d)  //If method returned true.
               alert('Exist');
            else
               alert('No Student Found')
        },
        error: function (msg) { alert(msg.d); }
    });
});

Also, include jquery base library file.

edited Dec 22, 2015 at 10:32

answered Dec 22, 2015 at 10:15

Rahul Singh

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10 Comments

Shaik Over a year ago

Thnaks for the reply [WebMethod] there is a error it says the name space WebMethod does not exist

Rahul Singh Over a year ago

@Shaik - Please include using System.Web.Services; in your file.

Shaik Over a year ago

I did that is working fine i have a quick question the string className if i use it then it is showing me an error

Rahul Singh Over a year ago

@Shaik - What error? Are you passing the value from your dropdown as parameters as I have shown?

Shaik Over a year ago

Passing From dropdown it is, Check_exam_id giving me the error not all code path returns the value string, string,string,string,

|

vignesh · Accepted Answer · 2015-12-22 10:14:16Z

2

Make it as a webmethod and call the method from jquery using ajax. Please find the below link, it contains the example for calling webmethods in asp.net using jquery ajax. http://www.aspsnippets.com/Articles/Calling-ASPNet-WebMethod-using-jQuery-AJAX.aspx

Hope this helps!

answered Dec 22, 2015 at 10:14

vignesh

838 bronze badges

Comments

MaxPayne999 · Accepted Answer · 2015-12-22 10:21:40Z

0

Use Jquery ajax method or use UpdatePanels

Create your method Check_exam_id as public static and decorate it as [WebMethod] And call the javascript function on click event of button as you call any other function.

    function DoWork(){
     $.ajax({
          url: 'YourPage.aspx/Check_exam_id',
          data: {}, //blank since you are sending nothing
          dataType:'JSON',
          type: 'POST',
          contentType:'application/json;charset=utf-8',
          success:function(){
          alert('Success');
          //Do whatever you want with the HTML
          },
         error:function()
         {
          alert('Error');
            }
         });
        }

answered Dec 22, 2015 at 10:21

MaxPayne999

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Comments

Deepak · Accepted Answer · 2015-12-22 11:02:15Z

$("#Check_examid").click(function (e) {
    e.preventDefault(); //To avoid postback
    //Get these values from dropdwon
    var className = $("#DD_class").val();
    var methodName = $("#DD_Method").val();
    var data = { "className": className , "MethodName": methodName };  
    $.ajax({
        type: "POST",
        dataType: "json",
        contentType: "application/json; charset=utf-8",
        url: "Default.aspx/Check_exam_id",
        data: JSON.stringify(data),
        success: function (response) {
            if(response!=null)  //If method returned true.
               alert('Exist');
$("DivId").html(response.d)
            else
               alert('No Student Found')
        },
        error: function (msg) { alert(msg.d); }
    });
});

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