how can i get the value of the file upload control

Question

how can i get the file upload control?? the file upload control is a child page and i want the value of it will display in a labelin a grdview as the parent page 

im using this code:

aspx page

<script type="text/javascript" langauge="javascript">

    function post_value() {

        var lblUpload = document.getElementById("upFile").value;

        window.opener.form1.upFile.value = lblUpload;

 

 

 window.close();

}

</script>

aspx.cs page

 protected void Button4_Click(object sender, EventArgs e)

        {

            if (upFile.HasFile)

            {

                upFile.SaveAs(Server.MapPath("upload_file") + @"\"  + upFile.FileName);

                Label1.Text = "File Uploaded: " + upFile.FileName;

                

            }

            else

            {

                Label1.Text = "No File Uploaded.";

            }

            this.Button4.Attributes.Add("onclick", "javascript:post_value()");

                

            

how can get the value of the the file upload control and send it to a label in a grid

plsss help me