In ASP.NET MVC, I wrote below code to give the textbox a initial value:
@Html.TextBoxFor(p => p.WEIGHT, new { tabindex = \"140\",
Maybe this? Untested.
@Html.TextBoxFor(p => (p.WEIGHT==null ? 0 : p.WEIGHT), new { tabindex = "140", @class = "mustInputText noime w50", maxlength = "8", rule = "InputOnlyNum" })