Pop up alert in C# code behind

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Hi All,

I tried to display pop up alert from c# code behind file.
My problem is that when the pop up statement is the only thing to be executed, it goes very well. But when it is combined with some other statement, it does not work.

For example,
this works

C#

if(condition)
            {
                System.Web.UI.ScriptManager.RegisterStartupScript(this, GetType(), "displayalertmessage", "alert('alert to be displayed');", true);
            }

but this don't

C#

if (condition)
               {
                   emp.logout();
                   System.Web.UI.ScriptManager.RegisterStartupScript(this, GetType(), "displayalertmessage", "alert('alert to be displayed');", true);
               }

I have tried various other ways but it never work with other code lines.
Anything I am missing?

What I have tried:

if (condition)
{
emp.logout();
System.Web.UI.ScriptManager.RegisterStartupScript(this, GetType(), "displayalertmessage", "alert('alert to be displayed');", true);
}

Posted 4-Oct-16 1:50am

planetz

Updated 5-Oct-16 21:53pm

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Comments

Karthik_Mahalingam 4-Oct-16 10:37am

what you doing inside emp.logout();

planetz 5-Oct-16 1:01am

emp.logout redirects to another page. I have to show pop up before calling the method.

Karthik_Mahalingam 5-Oct-16 1:12am

ok, what you can do is, show the alert first and then redirect to other page.

planetz 5-Oct-16 1:19am

have tried that also..but as F-ES Sitecore explained, since the html version will be prepared at the end and before that there is redirection, so pop up part will be discarded.

Karthik_Mahalingam 5-Oct-16 1:23am

i have posted a solution, give a try on it,
provided you are not doing any logic inside emp.logout();

planetz 5-Oct-16 1:42am

There is logic in emp.logout().

Karthik_Mahalingam 5-Oct-16 1:57am

ok.

3 solutions

Solution 2

If you want to show the alert before redirection you shall do it in javascript

C#

emp.logout();
               string redirectScript = " window.location.href = 'otherPage.aspx';";
               System.Web.UI.ScriptManager.RegisterStartupScript(this, GetType(), "displayalertmessage", "alert('alert to be displayed');" + redirectScript, true);

Posted 4-Oct-16 19:16pm

Karthik_Mahalingam

Comments

planetz 5-Oct-16 1:29am

I am not redirecting to aspx directly. The logout method contains some updates and then redirection. So I need to display alert and then move on to the method which includes the redirection.

Karthik_Mahalingam 5-Oct-16 1:56am

oh, then i will have to delete this solution.

planetz 5-Oct-16 1:56am

I have found a work around. To execute the logic separately and then redirecting separately. Since it is part of the answer, I am not marking your answer as solution.

Karthik_Mahalingam 5-Oct-16 1:56am

thats fine.

Solution 3

ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "alertMessage", "alert('show my alert message')", true);

Posted 5-Oct-16 21:53pm

Veeral Jani

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F-ES Sitecore · Accepted Answer · 2016-10-04T02:59:00

You have to understand the asp.net page lifecycle and the order things occur in. First your code-behind runs and that generates html (all RegisterStartupScript does is inject javascript into that html), that html is sent to the browser to execute, and it is at that point you see the popup.

If emp.logout redirects the user to a different page then to do that redirect all of the html generated by your code behind is simply discarded and replaced with a page that tells the browser to redirect, so the js that makes your alert is also discarded and is never executed.

The important thing to note is that your .net code isn't running inside the browser, you can't send anything to the browser before the page is finished, and the RegisterStartupScript call doesn't actually execute javascript.