Inputs inside Partialview takes value from main model - asp.net-mvc

Question

I render a PartialView inside my main View
View:
#model FullProductViewModel
...
<div class="send-container">
#Html.Partial("_CommentForm", new CommentViewModel { ProductId = Model.Id, Title = "" , Context="" })
</div>
...
I have a filed with name "Title" in Both my classes "FullProductViewModel" and "CommentViewModel".
_CommentForm PartialView:
#model CommentViewModel
<p class="page-title">#Resources.SendComment</p>
#using (Html.BeginForm("Comment", "Home", FormMethod.Post, new { #class = "form-comment form-submit" }))
{
#Html.AntiForgeryToken()
<div class="input-group">
#Html.LabelFor(model => model.Title)
#Html.ValidationMessageFor(model => model.Title, "", new { #class = "text-danger" })
#Html.EditorFor(model => model.Title, new { htmlAttributes = new { #class = "form-control" } })
</div>
<div class="input-group">
#Html.LabelFor(model => model.Context)
#Html.ValidationMessageFor(model => model.Context, "", new { #class = "text-danger" })
#Html.TextAreaFor(model => model.Context, htmlAttributes: new { #class = "form-control", rows = "8" })
</div>
<div class="input-group">
#Html.LabelFor(model => model.CaptchaCode)
#Html.ValidationMessageFor(model => model.CaptchaCode, "", new { #class = "text-danger" })
#Html.EditorFor(model => model.CaptchaCode, new { htmlAttributes = new { #class = "form-control" } })
</div>
<div class="captcha-wrapper">
<img alt="Captcha" id="imgcaptcha" src="#Url.Action("Captcha", "Captcha")" />
</div>
<button class="btn btn-submit" type="submit">#Resources.SendMessage</button>
}
The problem is "Title" inside PartialView take its value form "FullProductViewModel" model but not "CommentViewModel ". i can easily change the field name "Title" inside one of models to solve problem... but why this happened and how i can fix it without change field name?

Answer 1

Your Title property is conflicting with the #{ ViewBag.Title = ".. line of code in your view (the ViewBag code is used by the _Layout.cshtml file to set the global <title> attribute for the page).
All the HtmlHelper methods that generate form controls set the value by checking (in order)
ModelState
The ViewDataDictionary (ViewData or ViewBag)
The value of the models property
In your case, nothing has been added to ModelState. But because a value for Title has been added to the ViewDataDictionary, its that value which is used for the value of your textbox. The method never gets to read the actual value you have set in your model.
The only realistic option (unless you want to modify the code in the _Layout and all views that use it) is to change the name of the property.