How to get value from active-x Textbox control in Word

Create active-x Textbox control in Word. Enter some text in it like "box1box". Then using OpenXml Tool to open file and reflect code. You will not able to see the text string since they are images. Something like these:

   <w:object w:dxaOrig="1440" w:dyaOrig="1440">
      <v:shapetype id="_x0000_t75" coordsize="21600,21600" filled="f" stroked="f" o:spt="75" o:preferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:v="urn:schemas-microsoft-com:vml">
        <v:stroke joinstyle="miter" />
        <v:formulas>
          <v:f eqn="if lineDrawn pixelLineWidth 0" />
          <v:f eqn="sum @0 1 0" />
          <v:f eqn="sum 0 0 @1" />
          <v:f eqn="prod @2 1 2" />
          <v:f eqn="prod @3 21600 pixelWidth" />
          <v:f eqn="prod @3 21600 pixelHeight" />
          <v:f eqn="sum @0 0 1" />
          <v:f eqn="prod @6 1 2" />
          <v:f eqn="prod @7 21600 pixelWidth" />
          <v:f eqn="sum @8 21600 0" />
          <v:f eqn="prod @7 21600 pixelHeight" />
          <v:f eqn="sum @10 21600 0" />
        </v:formulas>
        <v:path gradientshapeok="t" o:connecttype="rect" o:extrusionok="f" />
        <o:lock v:ext="edit" aspectratio="t" />
      </v:shapetype>
      <v:shape id="_x0000_i1031" style="width:220.65pt;height:18pt" alt="altbox1" o:ole="" type="#_x0000_t75" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:v="urn:schemas-microsoft-com:vml">
        <v:imagedata o:title="" r:id="rId5" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" />
      </v:shape>
      <w:control w:name="TextBox1" w:shapeid="_x0000_i1031" r:id="rId6" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" />
    </w:object>