CODE EXAMPLE FOR CSHARP

checkbox value unchecked after return view model

@model BlogPostsVM
@using (Html.BeginForm("Index", "yourControllerName", FormMethod.Get))
{
    @Html.LabelFor(m => m.IncludeUserPostsOnly)
    @Html.CheckBoxFor(m => m.IncludeUserPostsOnly)
    <input type="submit" value="Search" />
}