Get input value of a textbox in asp.net mvc

The correct way to do this is through <form> . Using MVC and Razor, it is used as follows:

@model MeuProjeto.Models.MeuModel

@using (Html.BeginForm()) 
{
    @Html.TextBoxFor(model => model.MeuCampo)

    <button type="submit">Enviar</button>
}

Obviously, this only makes sense if you have a Model defined like this:

namespace MeuProjeto.Models
{
    public class MeuModel
    {
        public String MeuCampo { get; set; }
    }
}

The Controller will receive the form data as follows:

[HttpPost]
public ActionResult MinhaAction(MeuModel model) 
{
    // O valor do campo em tela vai estar preenchido em 
    // model.MeuCampo
}