Access textbox value from ashx page

This is my Form Tag from The Master Page:

<form id="form1" runat="server" action="Handler.ashx" method="POST" enctype="multipart/form-data">

I have a TextBox in my Content Page:

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

I want to access the TextBox value in the Handler.ashx page Or Send the TextBox value as a query string in the action attribute like this

<form id="form1" runat="server" action="Handler.ashx?textBoxVal=SOMETHING" method="POST" enctype="multipart/form-data">

Is this possible?

Tags: Visual Basic, ASP.NET, ASHX, Handler