how to format web grid columns with html helpers

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MVC4

var grid = new WebGrid(Model, rowsPerPage: 10, canPage: true, canSort: true);

@grid.GetHtml(

       columns: new[]
       {
        grid.Column("CompanyId",
                     style:"col7",
                     format:@<p>
                         <input type="text" id="HCompanyId" value="@item.CompanyId" />
                     </p>),
       grid.Column("CompanyName",
                    style: "col1",
format:(@item)=>Html.TextBoxFor(item.CompanyName)),

       grid.Column("CompanyUrl",
                    style: "col2",
                    format: @<text> <span id="companyurl" class="display-mode">@item.CompanyUrl</span>
        <input type="text" id="txtUrl" value="@item.CompanyUrl" class="edit-mode"/>
        </text>),

     grid.Column("",header:"Actions",
                 style: "col4",
                 format:@<p>
                     <input type="button" id="btnEdit" value="Edit" class="editdisplay-mode" />
                     <input type="button" id="btnSave" value="Save" class="Saveedit-mode" />
                 </p>),


       },
                 headerStyle: "webgridHeader",
                 tableStyle: "webgrid",
                 mode: WebGridPagerModes.All,
                 footerStyle: "webgridFooter",
                  htmlAttributes: new { id = "grdCompanies" })

CompanyName column of webgrid showing error "cannot convert lamdaexpression to sysstem.function dynamic object"

In this normal html controls are working fine but html helpers are not working.

I tried

grid.Column("CompanyName",style: "col1", format: (item)=>  @<text>@Html.TextBoxFor("item", (String)item.CompanyName)

Can anyone spot what I am doing wrong?