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Miquel Coll
Asked: 2020-06-30 01:15:34 +0800 CST 2020-06-30 01:15:34 +0800 CST

Create an alert after performing asynchronous action

  • 772

I have a function in the code behind of an aspx page made with Visual Studio that is called from javascript like this:

function cerrar(id) {
    document.getElementById('<%= btnBloquea.ClientID()%>').click();
    alert("Curso " + id + " bloqueado correctamente.");
}

The problem is that the btnBloquea function sometimes gives an error and is redirected to the error page (I already have it under control) but whether or not the javascript code gives an error, alertit is ALWAYS shown even if the function has an error since it is executed from asynchronous way.

The button definition:

<asp:Button id="btnBloquea" runat="server" OnClick="btnBloquea_Click" CssClass="hidden"/> //CssCLass hidden es simplement un display:none

And of the function in its minimum expression:

Protected Sub btnBloquea_Click(sender As Object, e As EventArgs)
    Dim idEvento As String
    Dim cerrado As Boolean

    idEvento = hdngroupid.Value()
    cerrado = False 

    'Aquí vienen varios cálculos para si realmente se puede o no cerrar.        

    If Not cerrado Then
          'Aquí me voy a una página de error y NO quiero mostrar ningún alert.
    Else
          'Aquí todo ha ido bien y quiero mostrar el alert.
    End If

End Sub

My questions are:

  1. How can I alert the user only if the result of the function is correct?
  2. Is there a way to launch the alert only when it click()has finished?
  3. Maybe I can create an alert from the code behind function?
javascript

1 Answers

  1. Best Answer

    To redirect before a problem you would use the Response.Redirect(), this way you will not return to the page that has the close() function

    To execute javascript code, use the

    ScriptManager.RegisterStartupScript Method

    Protected Sub btnBloquea_Click(sender As Object, e As EventArgs)
    Dim idEvento As String
    Dim cerrado As Boolean

    idEvento = hdngroupid.Value()
    cerrado = False 

    'Aquí vienen varios cálculos para si realmente se puede o no cerrar.        

    If Not cerrado Then
          Response.Redirect("Error.aspx")
    Else
        Dim script As String = String.Format("cerrar('{0}');", idEvento)
        ScriptManager.RegisterStartupScript(Me, Me.GetType, "cerrar", script, True)
    End If

End Sub
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