Technorati Tags: .NET,Razor,C#,MVC,HTML Starting from MVC 3 and up this issue has been addressed. From MVC 3 and up underscores in HTML attributes are automatically converted to dashes. Here’s an example: @Html.TextBox( "tbxOne", "", new { @data_id = "someId", @style= "width:120px; text-align:right;" }) This wil result in: <input data-id="someId" ......