如何在mvc4 razor中显示验证消息

Question

我是MVC Razor的新手,我想在文本框上实现验证消息.这里我动态创建一些文本框,如下所示:

查看代码:

foreach (var items in (IEnumerable<System.Data.DataRow>)Model.UsersOfList)
{

  @Html.TextBoxFor(m => m.LoginNameOfLoginInfoTab, new { @class = "textBox_LoginInfoAndPermission", @value = (Model.LoginNameOfLoginInfoTab = items["UserName"].ToString()), @id = ("txtUserLoginName" + Model.UsernameOfLoginInfoTab.Trim()) })

  @Html.ValidationMessageFor(m => m.LoginNameOfLoginInfoTab, null, new { @class = "ErrorMessage" })

  @Html.TextBoxFor(m => m.UsernameOfLoginInfoTab, new { @class = "textBox_LoginInfoAndPermission", @value = (Model.UsernameOfLoginInfoTab = items["FirstName"].ToString()), @id = ("txtUserName" + Model.UsernameOfLoginInfoTab.Trim()) })

  @Html.ValidationMessageFor(m => m.UsernameOfLoginInfoTab, null, new { @class = "ErrorMessage" })


}

在模块中,我编写了用于验证的代码,如下所示:

[Required (ErrorMessage="*")]
    public string UsernameOfLoginInfoTab
    {
        get;
        set;
    }


   [Required(ErrorMessage = "*")]
    public string LoginNameOfLoginInfoTab
    {
        get;
        set;
    }

现在,当创建了所有文本框并且为第一个循环迭代文本框显示一个验证消息时,它将自动显示在另一个文本框的前面,这是在第二个循环迭代中创建的.

请告诉我哪里出错了.

Answer 1

问题是因为您正在使用的表达式TextBoxFor和ValidationMessageForMVC用于为字段创建字符串名称并从中查找验证消息ModelState,在循环的整个迭代过程中始终是相同的.

你的方法似乎有点缺陷,所以我的答案更全面.

1)创建在结构上代表您要显示的信息的视图模型.

修复视图模型:

public class UserInfoViewModel
{
    [Required (ErrorMessage="*")]
    public string UserName { get; set; }


   [Required(ErrorMessage = "*")]
    public string LoginName { get; set; }
}

// I don't know if you actually need this or not, but your existing model may contain additional properties relevant to the view that I don't know about, so I'll keep it.
public class ListOfUsersViewModel
{
    public IList<UserInfoViewModel> UsersOfList { get; set; }
}

修复你的行动(我在这里说明这一点):

public ActionResult ListOfUsers()
{
     var users = GetUserDataRows(); // gets your collection of DataRows
     var model = new ListOfUsersViewModel
                     {
                         UsersOfList = users.Select(row = new UserViewModel { UserName = row["FirstName"], LoginName = row["UserName"] }).ToList()
                     };

     return View(model);                  
}

2)现在,您可以在视图中迭代用户并使用验证消息创建适当的字段.

我们称之为这个观点ListOfUsers.cshtml.在视图中包含您需要的任何其他内容,但请改用for循环.

@using(Html.BeginForm("ListOfUsers"))
{
    <ul>
    @for (var i = 0; i < Model.UsersOfList.Count; i++)
    {
       <li>
       @Html.TextBoxFor(m.UsersOfList[i].LoginName, new {@class="textbox_LoginInfoAndPermission"})
       @Html.ValidationMessageFor(m => m.UsersOfList[i].LoginName)

       @Html.TextBoxFor(m.UsersOfList[i].UserName, new {@class="textbox_LoginInfoAndPermission"})
       @Html.ValidationMessageFor(m => m.UsersOfList[i].UserName)
       </li>
    }
    </ul>
   <button type="submit">Submit changes</button>
}

这将导致每个项目的HTML都这样(0在名称和id中将是集合中用户的索引):

<li>
<input type="text" id="UsersOfList_0_LoginName" name="UsersOfList[0].LoginName" value="..." />
<span class="field-validation-valid" data-valmsg-for="UsersOfList_0_LoginName" ... ></span>

<input type="text" id="UsersOfList_0_UserName" name="UsersOfList[0].UserName" value="..." />
<span class="field-validation-valid" data-valmsg-for="UsersOfList_0_UserName" ... ></span>
</li>

3)创建一个动作来接收提交的更改.此操作将自动将提交的值绑定到model参数,并为您执行验证.你需要做的就是检查ModelState.IsValid.

[HttpPost, ActionName("ListOfUsers")]
public ActionResult ListOfUsersPost(ListOfUsersViewModel model)
{
    // at this point, model will be instantiated, complete with UsersOfList with values submitted by the user

    if (ModelState.IsValid) // check to see if any users are missing required fields. if not...
    {
         // save the submitted changes, then redirect to a success page or whatever, like I do below
        return RedirectToAction("UsersUpdated");
    }

    // if ModelState.IsValid is false, a required field or other validation failed. Just return the model and reuse the ListOfUsers view. Doing this will keep the values the user submitted, but also include the validation error messages so they can correct their errors and try submitting again
    return View("ListOfUsers", model);

}