Refresh DropDownList on main form from modal Button Click in ASP.Net

Hi

I have main form and modal form. Modal form is updating users table on sql server. After updating Reporter Name drop down list should update the added record. But it is not working when call fillreporter() sub procedure

Please help me to fix this

Thanks & Regards,

Harinda

    '------------------------ Add New user modal popup-----------------

    Protected Sub RegisterUser(sender As Object, e As EventArgs) Handles CmdCreateNewUser.Click
        Dim userId As Integer = 0
        'Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        ' Using cn As New SqlConnection(constr)
        Try
            If (Page.IsValid) Then
                cn.Open()
                Dim cmd As New SqlCommand("Insert_User")
                Dim da As New SqlDataAdapter()
                cmd.CommandType = CommandType.StoredProcedure

                cmd.Parameters.AddWithValue("@UserType", ddusertype.Text.Trim())
                cmd.Parameters.AddWithValue("@FullName", txtFullName.Text.Trim())
                cmd.Parameters.AddWithValue("@Email", txtEmail.Text.Trim())
                cmd.Parameters.AddWithValue("@Password", GetMD5Hash(txtPassword.Text.Trim()))

                cmd.Parameters.AddWithValue("@UserGroup", ddusergroup.Text.Trim())
                cmd.Parameters.AddWithValue("@Site", ddsiteadduser.Text.Trim())
                cmd.Parameters.AddWithValue("@ReportingManager", ddReportingManager.Text.Trim())
                cmd.Parameters.AddWithValue("@Department", dddepartmentadduser.Text.Trim())

                cmd.Parameters.AddWithValue("@Mobile", txtMobile.Text.Trim())
                cmd.Parameters.AddWithValue("@EmailNotificationGroup", EmailNotificationGroup.Text.Trim())
                cmd.Connection = cn
                userId = Convert.ToInt32(cmd.ExecuteScalar())
                Dim message As String = String.Empty
                Select Case userId
                    Case -1
                        message = "Full Name already exists.\Please choose a different username."
                        Exit Select
                    Case -2
                        message = "Supplied email address has already been used."
                        Exit Select
                    Case Else
                        message = "User Registration successful.\nUser Id: " + userId.ToString()

                        Exit Select
                End Select
                ClientScript.RegisterStartupScript([GetType](), "alert", (Convert.ToString("alert('") & message) + "');", True)
            End If
        Catch ex As SqlException
            MsgBox(ex.Message)
        Catch err As System.Exception
            MsgBox(err.Message)
        Finally
            cn.Close()
            FillPersonInvolved()
            FillReporters()
        End Try
    End Sub

    Public Sub FillReporters() 
        Try
            cn.Open() 
            If Not Me.IsPostBack Then
 
                Dim dal As SqlDataAdapter
                Dim dsl As DataSet 
                Dim dvl As DataView 
                dal = New SqlDataAdapter("select * from users1 order by FullName desc", cn)
                dsl = New DataSet
                dal.Fill(dsl, "users1")
                dvl = New DataView(dsl.Tables(0))
                dvl.Sort = "FullName"
 
                ddreporterName.DataSource = dvl
                ddreporterName.DataTextField = "FullName"
                ddreporterName.DataValueField = "FullName"
                ddreporterName.DataBind()
                ddreporterName.Items.Insert(0, New ListItem("", ""))
            End If 
        Catch ex As SqlException
            'MsgBox(ex.Message)
            Dim message As String = (ex.Message)
            Dim script As String = "window.onload = function(){ alert('"
            script &= message
            script &= "')};"
            ClientScript.RegisterStartupScript(Me.GetType(), "SuccessMessage", script, True)
        Catch err As System.Exception
            ' MsgBox(err.Message)
            Dim message As String = (err.Message)
            Dim script As String = "window.onload = function(){ alert('"
            script &= message
            script &= "')};"
            ClientScript.RegisterStartupScript(Me.GetType(), "SuccessMessage", script, True)
        Finally 
            cmd = Nothing
            cn.Close()
        End Try 
    End Sub