Develop Reference

Html button call a function in code behind and it fires only once

I have html button which calls a function in code behind and it fires only once.
I want it to fire event every time I click the button.
It is possibly duplicated but I have tried to add "!IsPostBack" but it doesn't work.
My ascx class:
<button runat="server" type="button" class="btn btn-report" onserverclick="OnReportBtnClick" id="reportBtn">
<i class="glyphicon glyphicon-floppy-disk"></i>
</button>
I have to use html button, not <asp:Button> because <asp:Button> doesn't let me to insert <i> tag inside.
Here is my code behind:
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack == false)
{
try
{
reportBtn.ServerClick += OnReportBtnClick;
}
catch (Exception ex)
{
}
}
}
//this method is called only once even I click the button many times afterwards.
protected void OnReportBtnClick(object sender, EventArgs e)
{
try
{
// Set file name
string pdfName = SPContext.Current.Web.Title + fileType;
CultureInfo provider = CultureInfo.InvariantCulture;
DateTime startDate = DateTime.MinValue;
if (!string.IsNullOrEmpty(report_startDate_datePicker.Value))
startDate = DateTime.ParseExact(report_startDate_datePicker.Value, format, provider);
DateTime endDate = DateTime.MaxValue;
if (!string.IsNullOrEmpty(report_endDate_datePicker.Value))
endDate = DateTime.ParseExact(report_endDate_datePicker.Value, format, provider);
// Provisioning data for report
var report = GetReport(startDate, endDate);
// Merger data to template html
byte[] data = GetPdfData(htmlTemplate, report);
//Respond report to client
RenderResponse(pdfName, data);
}
catch (Exception ex)
{
LoggingService.LogError(LoggingService.NTT_ERROR,
string.Format("ERROR: {0} - SOURCE: {1} | {2}", ex.Message, ex.Source, System.Reflection.MethodBase.GetCurrentMethod().Name));
}
}
//I think the problem could be this method.
//I return a pdf file to client
private void RenderResponse(string pdfName, byte[] data)
{
try
{
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ContentType = "application/pdf";
HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename=" + pdfName);
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
HttpContext.Current.Response.BinaryWrite(data);
HttpContext.Current.Response.End();
HttpContext.Current.ApplicationInstance.CompleteRequest();
}
catch (Exception ex)
{
LoggingService.LogError(LoggingService.NTT_ERROR,
string.Format("ERROR: {0} - SOURCE: {1} | {2}", ex.Message, ex.Source, System.Reflection.MethodBase.GetCurrentMethod().Name));
}

You can use a LinkButton
<asp:LinkButton runat="server" ID="ReportBtn" Text="<i class='glyphicon glyphicon-floppy-disk'></i>" OnClick="ReportBtn_Click" CssClass="btn btn-report" />
in .cs page
protected void ReportBtn_Click(object sender, EventArgs e)
{
//your code
}
They do support html in the text field.

asp.net Dropdownlist not refreshing after being removed

I have a 2 drop down lists with company name and company addresses and a remove button linked to a stored procedure. Addresses is not being refreshed even though I am calling databind() on that address drop down List. Can anyone point me out in the right direction?
//Button to remove Company
protected void btnremovecompany_2(object sender, EventArgs e)
{
if (ddlcompanyaddress2.SelectedIndex != 0) /*checked to see if an address is Selected first*/
{
string confirmValue = Request.Form["confirm_value"];
if (confirmValue == "Yes")/* if yes is clicked then procedd to deactivate that company address*/
{
String strConnString = ConfigurationManager.ConnectionStrings["DBConnection"].ConnectionString;
SqlConnection con = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "usp_update_company_active";
cmd.Parameters.Add("#companyname", SqlDbType.VarChar).Value = ddlcompany2.SelectedItem.Text.Trim();
cmd.Parameters.Add("#address", SqlDbType.VarChar).Value = ddlcompanyaddress2.SelectedItem.Text.Trim();
cmd.Parameters.Add("#category", SqlDbType.VarChar).Value = ddlTrades2.SelectedItem.Text.Trim();
cmd.Connection = con;
**ddlcompanyaddress2.DataBind();**
try
{
con.Open();
cmd.ExecuteNonQuery();
}
catch (Exception ex)
{
throw ex;
}
finally
{
/*Display message saying company is deactivated*/
string message = "Company has been removed";
string script = "window.onload = function(){ alert('";
script += message;
script += "')};";
ClientScript.RegisterStartupScript(this.GetType(), "SuccessMessage", script, true);
con.Close();
con.Dispose();
}
}
else
{
/*if canceled is clicked then display no changes*/
this.Page.ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('No Changes were made!')", true);
}
}
else
{
string message = "Please pick an address first.";
string script = "window.onload = function(){ alert('";
script += message;
script += "')};";
ClientScript.RegisterStartupScript(this.GetType(), "SuccessMessage", script, true);
}
}

You might be missing the datasource for your dropdown list. I am unable to find datasource in your code. You have just called databind method.
Can you please bind the datasource?

added this code to the try{} area and it resets all the dropdowns with fresh data.
ddlgettrades2();
getcompany2(ddlTrades2.SelectedItem.Text);
getaddress2(ddlcompany2.SelectedItem.Text);

How to execute a C# method from JavaScript code without refreshing the page?

How can i execute a C# method from JavaScript Code without refreshing the page?
this is the function that i want to execute:
protected void submitData(object sender, EventArgs e)
{
MySqlConnection conn = new MySqlConnection();
string worker = workerNameInput.Text;
string project = projectNameInput.Text;
string status = statusInput.Text;
string color = colorInput.Text;
if (worker.Equals("") || project.Equals("") || status.Equals("") || color.Equals(""))
return;
try
{
conn = new MySqlConnection();
conn.ConnectionString = connectionString;
conn.Open();
string com = "insert into " + table + " values ('" + worker + "','" + project + "','"+ status + "','"+ color + "');";
MySql.Data.MySqlClient.MySqlCommand command = new MySql.Data.MySqlClient.MySqlCommand(com, conn);
string res = command.ExecuteNonQueryAsync().ToString();
Console.WriteLine(res);
Console.WriteLine("Insert command pass successfully");
}
catch (Exception ex)
{
Console.WriteLine("Failed to update database with \"insert\" command");
Console.WriteLine(ex.Message);
}
}
and i know that i should use
public partial class Home : System.Web.UI.Page, IPostBackEventHandler
and
public void RaisePostBackEvent(string eventArgument)
{
submitData(null, null);
}
inside the JS i used this code:
project.updateTable = function() {
var projectName = project.projectName();
var workerName = project.workerName();
var status = project.status();
var color = project.color();;
if (projectName == "" || workerName == "" || status == "" || color == "")
return;
project.rows.push({ projectName: ko.observable(projectName), workerName: ko.observable(workerName), status: ko.observable(status), color: ko.observable(color) });
project.projectName("");
project.workerName("");
project.status("");
project.color("");
var argumentString = projectName + "," + workerName + "," + status + "," + color;
var pageId = '<%= enterToDB.ClientID%>';
__doPostBack(pageId, argumentString);
};
This is how i configure my button:
<p><asp:Button runat="server" ID="enterToDB" Text="Add Project" data-bind="click: updateTable" onmouseover="this.style.background='orange', this.style.color='darkslateblue'" onmouseout="this.style.background='darkslateblue', this.style.color='orange'" /></p>
Can you correct my mistakes please?
and show me where i'm wrong?

You can use ASP.NET WebForm's UpdatePanel control to run the code-behind async. This is commonly known as "AJAX" (Asynchronous JavaScript and XML) or "XHR" (XML HTTP Request), and is built-in to the WebForms framework.
Here's a great resource on MSDN to get you started: https://msdn.microsoft.com/en-us/library/bb399001.aspx

It is possible to call JavaScript functions from C# form or class and to call C# functions from the JavaScript.
Javascript to C#
-------C# code--------------------
[System.Runtime.InteropServices.ComVisible(true)]
// execute the following instruction in the form initialisation
WebBrowser1.ObjectForScripting = this ;
// define a public method
public void ShowMessage (string msg) { MessageBox.Show(msg); }
-------HTML and Javascript----------------
<input type="button" value="JavaScript is calling Dotnet"
onclick="window.external.ShowMessage('JavaScript message');" />
C# to Javascript
-------C# code--------------------
object [] MyArgs = { "Hello" } ; WebBrowser1.Document.InvokeScript("MyJsFunction",MyArgs ) ;
-------Javascript----------------
function MyJsFunction(s) { alert(s) ; }

Show message only on first access to the web page in c#

With this code I show JavaScript alert message box in ASP.Net from server side using C#.
But I need show the message only on first access to the web page, how to do resolve this ?
Please help me.
My code below, thank you in advance.
protected void Page_Load(object sender, EventArgs e)
{
string message = "Hello!";
System.Text.StringBuilder sb = new System.Text.StringBuilder();
sb.Append("<script type = 'text/javascript'>");
sb.Append("window.onload=function(){");
sb.Append("alert('");
sb.Append(message);
sb.Append("')};");
sb.Append("</script>");
ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", sb.ToString());
}

You need to check that the page is not posting back before you display your alert:
if (!IsPostBack)
{
string message = "Hello!";
System.Text.StringBuilder sb = new System.Text.StringBuilder();
sb.Append("<script type = 'text/javascript'>");
sb.Append("window.onload=function(){");
sb.Append("alert('");
sb.Append(message);
sb.Append("')};");
sb.Append("</script>");
ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", sb.ToString());
}
Updates:
You can create a cookie to track the alert so it does not display after displaying during the initial page load:
private bool Alerted()
{
if (Request.Cookies["alerted"] != null)
return Server.HtmlEncode(Request.Cookies["alerted"].Value) == "true";
else
{
Response.Cookies["alerted"].Value = "true";
Response.Cookies["alerted"].Expires = DateTime.Now.AddDays(10);
return false;
}
}
Usage:
if(!Alerted())
{
// alert script here
}

how to stop calling onbeforeunload event while page refresh

I am trying to update database while user closing browser/tap.I tried with onbeforeunload function and its working fine but even in page refreshing.Here is code what i tried
MyJSP :
<script type="text/javascript">
var refresh=false;
$(window).keydown(function(event){
if(event.keyCode==116)
{
refresh=true;
}
})
$(window).on('beforeunload', function(){
if(refresh==false)
{
$.get("BrowserCloseServlet", function() {
});
}
});
</script>
MyServlet :
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
#SuppressWarnings("unused")
String getId = request.getParameter("getid");
Connection con = null;
PreparedStatement pst = null;
PreparedStatement pst2 = null;
ResultSet rst = null;
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/raptor1_5", "root", "");
String query = "select NoOfCount from tbl_BroserCloseTable ";
String query2 = "update tbl_BroserCloseTable set NoOfCount= ? where Sno= ?";
// Statement st = con.createStatement();
// st.executeUpdate("");
pst = con.prepareStatement(query);
rst = pst.executeQuery(query);
if (rst.next()) {
int count = rst.getInt(1);
System.out.println("Actuall count is :" + count);
count -= 1;
pst2 = con.prepareStatement(query2);
pst2.setInt(1, count);
pst2.setInt(2, 1);
pst2.executeUpdate();
System.out.println("Updated successfully...");
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
con.close();
rst.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Its working fine(not update DB while click f5 button) but if the user click on refresh button then that servlet page called and updated DB.I want to stop calling onbeforeunload when click on refresh button in browser.
Update :
I only want to know how make that refresh=false; while click on refresh button in browser.
How to do this one?