Question

在我的mvc网站中，我有一个以表格格式显示用户详细信息的页面，并且有一个链接可以编辑所选行，当点击编辑时显示错误信息如下所示

参数字典包含'Sample_MVCApp.Controllers.UserController'中方法'System.Web.Mvc.ActionResult UserEdit（Int32）'的非可空类型'System.Int32'的参数'regNo'的空条目。可选参数必须是引用类型，可空类型，或者声明为可选参数。参数名称：参数

代码如下：

模型：

public class UserModels
{
    [Key]
    public int RegNo { get; set; }

    [Required(ErrorMessage="First name required")]
    public string FirstName { get; set; }

    [Required]
    public string LastName { get; set; }
    public string Address { get; set; }

    [Required]
    [StringLength(20)]
    public string Email { get; set; }

    [Required(ErrorMessage="Date field is required")]
    [DataType(DataType.Date)]
    [DateRange(ErrorMessage = "Must be between 18 and 65 years ago")]
    public DateTime DOB { get; set; }

    [Range(100,10000)]
    public decimal Salary { get; set; }
}

控制器：

public ActionResult UserEdit(int regNo)
    {
        Users user = new Users();
        return View(user.GetUserDetailsForEdit(regNo));
    }

页：

@using (Html.BeginForm()) {
@Html.ValidationSummary(true)

<fieldset>
    <legend>UserModels</legend>

    @Html.HiddenFor(model => model.RegNo)

    <div class="editor-label">
        @Html.LabelFor(model => model.FirstName)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.FirstName)
        @Html.ValidationMessageFor(model => model.FirstName)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.LastName)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.LastName)
        @Html.ValidationMessageFor(model => model.LastName)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Address)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Address)
        @Html.ValidationMessageFor(model => model.Address)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Email)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Email)
        @Html.ValidationMessageFor(model => model.Email)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.DOB)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.DOB)
        @Html.ValidationMessageFor(model => model.DOB)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Salary)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Salary)
        @Html.ValidationMessageFor(model => model.Salary)
    </div>

    <p>
        <input type="submit" value="Save" />
    </p>
</fieldset>
}

在我的索引页面中，我使用下面的行来获取id

@Html.ActionLink("Edit", "UserEdit", new { id=item.RegNo })

单击edit时，参数值为null，但url包含值为 “/用户/ USEREDIT / 3”

如何解决这个问题？

Answer 1

您的操作方法参数名称与ActionLink参数名称不匹配。改变

public ActionResult UserEdit(int regNo)

到

public ActionResult UserEdit(int id)

或更改您的行动链接

@Html.ActionLink("Edit", "UserEdit", new { id=item.RegNo })

到

@Html.ActionLink("Edit", "UserEdit", new { regNo=item.RegNo })

它应该有用。

在mvc中编辑行时出错

1 个答案: