Change QueryString value based on TextBox and reload page in ASP.Net

 I have a child and master in a page.

Need to replace and re-load page once the master saved & id saved in a textbox. Please help

 Note: some time the url is localhost & some time over internet like www......

                    If Request.QueryString("ID") = "add" Then
                        Dim url As String = HttpContext.Current.Request.Url.AbsoluteUri
                        Dim separateURL() As String = url.Split("?")
                        Dim queryString As NameValueCollection = System.Web.HttpUtility.ParseQueryString(separateURL(1)) 'Pass the Querystring part.
                        queryString.Remove("add")
                        queryString.Set("add", txtInvId.Text)
                        url = separateURL(0) + "?" + queryString.ToString()
                        'reloadpage code?
                    Else
                        LoadInvDet(Request.QueryString("id"))
                    End If