ASP.NET Webforms - Calling a C# method with AJAX

Question

I've an asp button on an aspx :

<asp:Button id="btnReport2" name="btnReport2"  runat="server"  class="gradientBlueBtn" Text="Show Report" OnClientClick="Alert();" ToolTip="Report"/>

As you can see, I'm calling a javascript function which uses AJAX to call a C# method. I'm doing this way :

<script>
    function Alert()
            {
                $.ajax({
                    type: "POST",
                    url: "Selection.aspx/GetReport",
                    contentType: 'application/json; charset=utf-8',
                    dataType: 'json',
                    success: function()
                    {
                        alert('success');
                    },
                    error: function()
                    {
                        alert('error');
                    }
                });

            }
</script>

The thing is, I'm always getting the error message when I'm clicking on the button. Is there something I'm doing wrong?

EDIT : The C# method. I've put a breakpoint to see if the method is called but apparently it isn't.

public void GetReport()
{
    AddFilters();
    decimal localCurrencyRate;            
    App_Data.BulkImportDSTableAdapters.ClientsTableAdapter tadptClients = new  App_Data.BulkImportDSTableAdapters.ClientsTableAdapter();
    string legalEntityID = string.Empty;           
    if (txtSrcSys.Text != null)
    {
        DataTable dtSSYS = tadptClients.GetLegalEntityID(txtSrcSys.Text);
        if (dtSSYS.Rows.Count > 0)
        {
            legalEntityID = Convert.ToString(dtSSYS.Rows[0][0]);
        }
    }
    DateTime dtInvoiceFrom = DateTime.ParseExact(txtInvoiceFrom.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture);
    DateTime dtInvoiceTo = DateTime.ParseExact(txtInvoiceTo.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture);
    string strInvoiceFrom = String.Format("{0:yyyyMMdd}", dtInvoiceFrom);
    string strInvoiceTo = String.Format("{0:yyyyMMdd}", dtInvoiceTo);
    string localCurrency = dbcon.getLocalCurrency(legalEntityID);
    DataSet localCurrencyDs = dbcon.getCurrencyRate(localCurrency, strInvoiceFrom);
    if (Convert.ToDecimal(localCurrencyDs.Tables[0].Rows[0]["rate"]) == 0)
        localCurrencyRate = Convert.ToDecimal(localCurrencyDs.Tables[0].Rows[1]["rate"]);
    else
        localCurrencyRate = Convert.ToDecimal(localCurrencyDs.Tables[0].Rows[0]["rate"]);
    string fileQuery = string.Empty;
    if (cbxExpYes.Checked == true && cbxExpNo.Checked == false)
    {                
        fileQuery = File.ReadAllText(Server.MapPath("~/temp/Query.txt")).Replace("{1}", "XFORM_AREA.IMPORT_GE_MAIN_V15BIS m");
        fileQuery = fileQuery.Replace(":param1", localCurrencyRate.ToString());
        fileQuery = fileQuery.Replace("{0}", qb.getFilters().Replace("P.", "m."));
    }
    if (cbxExpYes.Checked == false && cbxExpNo.Checked == true)
    {               
        fileQuery = File.ReadAllText(Server.MapPath("~/temp/Query.txt")).Replace("{1}", "PREIMPORT_GE_MAIN m");
        fileQuery = fileQuery.Replace(":param1", localCurrencyRate.ToString());
        fileQuery = fileQuery.Replace("{0}", qb.getFilters().Replace("P.", "m."));
    }
    if (cbxExpYes.Checked == true && cbxExpNo.Checked == true)
    {               
        fileQuery = File.ReadAllText(Server.MapPath("~/temp/QueryUnion.txt"));
        fileQuery = fileQuery.Replace("{ParamValues}", "pg.DEFVAL ");
        fileQuery = fileQuery.Replace("{ParamTab}", "ref_var_def pg");
        fileQuery = fileQuery.Replace("{ParamCond}", "pg.NM = 'WL_REPORTING_CUR'");
        fileQuery = fileQuery.Replace("{0}", qb.getFilters().Replace("P.", "m."));
        fileQuery = fileQuery.Replace("{1}", qb.getFilters().Replace("P.", "i."));
    }
    ASPxPivotGrid1.OptionsFilter.ShowOnlyAvailableItems = true;
    int indexTravFullName = 0;
    int indexEndTravFullName = 0;
    string paramToRemove = string.Empty;

    indexTravFullName = fileQuery.IndexOf("AND PR.ST_TRAVELLER_FULL_NAME LIKE");
    if (indexTravFullName > 0)
    {
        indexEndTravFullName = fileQuery.Substring(indexTravFullName).IndexOf("AND", 3);
        paramToRemove = fileQuery.Substring(indexTravFullName, indexEndTravFullName);
        fileQuery = fileQuery.Replace(paramToRemove, string.Empty);
    }

    if (!string.IsNullOrEmpty(fileQuery))
    {


        DataSet dsTravels = new DataSet();

        oCmd.CommandText = fileQuery;
        oCmd.CommandType = CommandType.Text;
        oCmd.Connection = oConn;
        odpter.SelectCommand = oCmd;


        odpter.SelectCommand.Parameters.Add(":pSourceSystem", txtSrcSys.Text);
        odpter.SelectCommand.Parameters.Add(":pInvoiceFrom", strInvoiceFrom);
        odpter.SelectCommand.Parameters.Add(":pInvoiceTo", strInvoiceTo);

        if (!String.IsNullOrWhiteSpace(txtCustomNr.Text))
        {
            odpter.SelectCommand.Parameters.Add(":pCustomerNr", txtCustomNr.Text);
        }
        if (!String.IsNullOrWhiteSpace(txtIATA.Text))
        {
            odpter.SelectCommand.Parameters.Add(":Iata", txtIATA.Text);
        }
        if (!String.IsNullOrWhiteSpace(txtCurrCode.Text))
        {
            odpter.SelectCommand.Parameters.Add(":CurrCode", txtCurrCode.Text);
        }
        if (!String.IsNullOrWhiteSpace(txtInvoiceNrFrom.Text))
        {
            odpter.SelectCommand.Parameters.Add(":pInvoiceNrFrom", txtInvoiceNrFrom.Text);
        }
        if (!String.IsNullOrWhiteSpace(txtInvoiceNrTo.Text))
        {
            odpter.SelectCommand.Parameters.Add(":pInvoiceNrTo", txtInvoiceNrTo.Text);
        }
        if (!String.IsNullOrWhiteSpace(txtDossierNrFrom.Text))
        {
            odpter.SelectCommand.Parameters.Add(":pDossierNrFrom", txtInvoiceNrFrom.Text);
        }
        if (!String.IsNullOrWhiteSpace(txtDossierNrFrom.Text))
        {
            odpter.SelectCommand.Parameters.Add(":pDossierNrTo", txtInvoiceNrFrom.Text);
        }
        if (!String.IsNullOrWhiteSpace(txtTravellerName.Text))
        {
            odpter.SelectCommand.Parameters.Add(":pTravellerName", txtTravellerName.Text);
        }
        if (chbxSale.Checked)
        {
            odpter.SelectCommand.Parameters.Add(":pSale", "SA");
        }
        if (chbxRefund.Checked)
        {
            odpter.SelectCommand.Parameters.Add(":pRefund", "RE");
        }
        if (hfTravelWith.Value.Contains("chbxairs"))
        {
            odpter.SelectCommand.Parameters.Add(":pProductAir", "7");
        }
        if (hfTravelWith.Value.Contains("chbxhotels"))
        {
            odpter.SelectCommand.Parameters.Add(":pProductHotel", "3");
        }
        if (hfTravelWith.Value.Contains("chbxcars"))
        {
            odpter.SelectCommand.Parameters.Add(":pProductCar", "1");
        }
        if (hfTravelWith.Value.Contains("chbxrails"))
        {
            odpter.SelectCommand.Parameters.Add(":pProductRail", "6");
        }
        if (hfTravelWith.Value.Contains("chbxmisc"))
        {
            odpter.SelectCommand.Parameters.Add(":pProductMisc", "9");
        }

        if (!String.IsNullOrWhiteSpace(txtBatchNr.Text))
        {
            odpter.SelectCommand.Parameters.Add(":pBatchNr", txtBatchNr.Text);
        }


        odpter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
        odpter.Fill(dsTravels, "ReportTab");
        int count = dsTravels.Tables[0].Rows.Count;
        DataTable dt = dsTravels.Tables[0];


        if (dt.Rows.Count > 0)
        {

            ASPxPivotGrid1.DataSource = dt;
            ASPxPivotGrid1.DataBind();
            Session["dtReport"] = dt;
            //ASPxPivotGrid1.Prefilter.CriteriaString = "[" + ""  + "]";
        }
    }
}

Answer 1

Your method must be declared as static and decorated with [WebMethod] . So, your method should be:

[WebMethod]
public static void GetReport()
{
    // Your code here
}

For more information, please take a look at this post .

EDIT!!!

I see you use some controls in your code (like txtInvoiceFrom , txtInvoiceTo ). After making your method static , you cannot access those controls anymore. To solve this problem, please follow these steps (take txtInvoiceTo as an example):

1. Don't get data by using txtInvoiceTo.Text or something similar. Pass it as a parameter.
2. Get txtInvoiceTo data from client-side, using jQuery or something else (your choice), and pass it to the Ajax to post to server.
3. To get txtInvoiceTo data by jQuery , you can do: $('#<%= txtInvoiceTo.ClientID %>').val()

Answer 2

Your method must be static and decorated with [WebMethod] as below, why should make it static and decorate with [WebMethod]?

[WebMethod]
public static void GetReport()
{
    // Your code here
}

$.ajax({
    type: "POST",
    url: "Selection.aspx/GetReport",
    data: JSON.stringify({ parametername : "Parameter Value" }),
    contentType: 'application/json; charset=utf-8',
    dataType: 'json',
    success: function()
    {
        alert('success');
    },
    error: function()
    {
       alert('error');
    }
});

Answer 3

Try with this type of format.

 [System.Web.Services.WebMethod]
 public static void GetReport()
 {
 }


 [System.Web.Services.WebMethod]
 public static void GetReport(string name)
 {
 }

Get more detail from

http://www.aspsnippets.com/Articles/Call-ASPNet-Page-Method-using-jQuery-AJAX-Example.aspx

Answer 4

There are 3 points that must be checked:

1. async true in the ajax call. Example:

    $.ajax({ type: "POST", url: "<%=System.Configuration.ConfigurationManager.AppSettings["URL"]%>ClassEadArquivos.aspx/deleteArquivo", date: "{FileCode: '" +FileCode + "',CodigoAulaEad: '" + <%=CodigoAulaEad.Value%> + "'}", async: true, contentType: "application/json", success: function (response) {

2. static and async method in codebehind. Example:

    [WebMethod()] public static async System.Threading.Tasks.Task<string> deleteFile(string fileCode, stringCode ClassEad) {

3. if the codebehind initial method calls other asynchronous methods must all be marked as asynchronous and static.