Question

I have the following View, Controller and Comment.cs code, but I get an error,

The model item passed into the dictionary is of type ‘TMPBlog.Models.Comment’, but this dictionary requires a model item of type ‘TMPBlog.Models.Post’.

If I don’t enter any text into the two required text fields @Html.TextBox(“CommentEmail”) and @Html.TextArea(“CommentDetail”, new { cols = “65”, rows = “7” }), if I do it works fine.

Controller code,

public ActionResult Index(int PostID)
{
    Post post = db.Posts.Single(p => p.PostID == PostID);
    return View(post);
}

[HttpPost]
public ActionResult Index(Comment comment)
{
    if (ModelState.IsValid)
    {
        string CommentEmail = comment.CommentEmail;

        string CommentDetail = comment.CommentDetail;
        CommentDetail = CommentDetail.Replace("\n", "<br />");
        comment.CommentDetail = CommentDetail;

        db.Comments.AddObject(comment);
        db.SaveChanges();

        return RedirectToAction("CommentResponse", new { id = comment.CommentID });
    }
    return View(comment);
}

Comment.cs,

using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

namespace TMPBlog.Models
{
    [MetadataType(typeof(CommentMetaData))]
    public partial class Comment
    {
    }

    public class CommentMetaData
    {
        [Required(ErrorMessage = "You must enter an email address!")]
        public object CommentEmail { get; set; }

        [Required]
        public object CommentDetail { get; set; }
    }
}

View,

@model TMPBlog.Models.Post

@Html.ValidationSummary("There is an error")

@using (Html.BeginForm())
{

    @Html.Hidden("CommentDate", String.Format("{0:yyyy-MM-dd HH:mm}", DateTime.Now))
    @Html.Hidden("PostCommentFK", @Html.DisplayFor(model => model.PostID))

    <br />
    <span class="BlueHeading">Add Your Comments Here!</span>
    <br /><br />

    <div class="editor-label">
        Email Address
    </div>
    <div class="editor-field">
        @Html.TextBox("CommentEmail")
        @Html.ValidationMessage("CommentEmail", "*")
    </div>

    <div class="editor-label">
        Comments
    </div>
    <div class="editor-field">
        @Html.TextArea("CommentDetail", new { cols = "65", rows = "7" })
        @Html.ValidationMessage("CommentDetail", "*")
    </div>

    <div class="editor-field">
        @Html.CheckBox("CommentTicked") Email me when others comment
    </div>
    <p>
        <input type="submit" value="Add Comment" />
    </p>
}

How do I solve this?

Cheers,

Mike.

Answer 1

Your view is strongly typed to TMPBlog.Models.Post, but in your POST controller action you are passing a comment:

return View(comment);

This obviously is wrong.

You could simply return the same view:

return View();

Since everything is stored in the modelstate the view will be correctly redisplayed with the corresponding error messages.

Also the following line:

@Html.Hidden("PostCommentFK", @Html.DisplayFor(model => model.PostID))

could probably be simplified:

@Html.Hidden("PostCommentFK", Model.PostID)