Java script alert msg in code behind Asp.net 3.5 - asp.net

Question

How to use Java script alert msg in code behind? This message will be display after save the data.
Here is my code,
enter code here
Protected Sub Add_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Add.Click
'add new class
Dim DbClassMst = New ClassMst()
Dim dsClass As DataSet
Dim status As Integer = 0
Dim ResourceObject As Object
' 画面リソース定義
If SessionCtl.GetSession("RES_LANG").ToString = ResourceBase.LOCALE_JA Then
ResourceObject = New ResourceJa(SessionCtl.GetSession("RES_LANG"))
Else
ResourceObject = New ResourceEn(SessionCtl.GetSession("RES_LANG"))
End If
If NewClass.Text = "" Then
lblErrMsg.Text = ResourceObject.getMsg(ResourceBase.NEW_CLASS_REG)
Exit Sub
Else
'check to allow unique class
dsClass = DbClassMst.DisplayClass1(NewClass.Text)
If Trim(dsClass.Tables(0).Rows.Count > 0) Then
status = 1
End If
If dsClass.Tables(0).Rows.Count < 10 Then
If status = 0 Then
'insert class
DbClassMst.InsertClassNew(NewClass.Text, dsClass.Tables(0).Rows.Count + 1)
PopulateClassName()
NewClass.Text = ""
Dim AlertMsg As String = ""
AlertMsg = "<script language='javascript'>alert('Data has been saved');</script>"
*********Here I need alert msg.
Else
lblErrMsg.Text = ResourceObject.getMsg(ResourceBase.NEW_CLASS_EXIST)
Exit Sub
End If
Else
lblErrMsg.Text = ResourceObject.getMsg(ResourceBase.NEW_CLASS_MAX)
End If
End If
End Sub
but is not working. give me an idea.

Answer 1

A better way to do this is to have this as a utility method in a common class:
Friend Module MyUtilities
Public Sub Alert(ByVal page As Page, ByVal message As String)
Dim alertMessage As String = "alert('" & message & "');"
page.ClientScript.RegisterStartupScript(page.[GetType](), "showAlert", alertMessage, True)
End Sub
End Module
This can be used in a page like this:
MyUtilities.Alert(Me, "Sample alert!!!!!")
Your code looks so simpler. Hope this helps!

Answer 2

You should register this script to your page, so this script will be sent to the client.
Page.ClientScript.RegisterStartupScript(typeof(YourPage),
"myScripts",
"<script language='javascript'>alert('Data has been saved');</script>");

Answer 3

Dim someScript As String = ""
someScript = "alert('Your Leave request has been registered');"
Page.ClientScript.RegisterStartupScript(Me.GetType(), "onload", someScript)