How to bind the Iframe control from Data base when View button click in WebGrid Control in MVC4 with C#

C# Source Code 
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public ActionResult ViewPDFDocument(int? Id)
        {
            var SRepository = new SRepository();
            var downloadFileName = SRepository .GetDownloadFileName(Id);
            byte[] imageByteData = SRepository .GetPdfFileContent(Id);
            string imageBase64Data = Convert.ToBase64String(imageByteData, 0, imageByteData.Length);
            MemoryStream workStream = new MemoryStream();
            workStream.Write(imageByteData, 0, imageByteData.Length);
            workStream.Position = 0;
            Response.AppendHeader("Content-Disposition", "inline; filename=" + downloadFileName.ToString().Trim());
            Response.ContentType = "application/pdf";
            return File(workStream, "application/pdf", downloadFileName.ToString().Trim());
        }

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In the View  :-

<div id="">
        <table >
            <tr>
                <td align="left" colspan="2" style="vertical-align:top;">
                    @grid.GetHtml(tableStyle: "webgrid-table",
                        headerStyle: "webgrid",
                        footerStyle: "webgrid-footer",
                        alternatingRowStyle: "webgrid-alternating-row",
                        rowStyle: "webgrid-row-style",
                    columns:
                     grid.Columns
                        (
                            grid.Column("CompanyName", "Company Name"),
                            grid.Column("FileName", "FileName "),
                            grid.Column("FileUploadDate", "File Uploaded Date"),
                           grid.Column(format: @<a href="~/SupController/ViewPDFDocument/@item.FileUploadId" target="iframe_a" style="color:blue;">&nbsp;View&nbsp;   </a>)
                        ))
                 </td>
            </tr>
            <tr>
                <td>
                    <image src='/SupController/ViewPDFDocument/<%= Html.Encode(Model.Id) %>' alt="" style="visibility:hidden;" />
                </td>
            </tr>
        </table>
        <iframe src="" name="iframe_a" style="height: 1000px; width: 1350px;border:1px solid;border-color:lightgray;"></iframe>
      
    </div>