Question

我在此表单上有三个表格。下拉列表是在我们的数据库中显示所有可能的品牌名称，并返回该品牌的UID。我尝试了许多不同的方法来解决这个问题，但无济于事。目前我收到错误消息，＆＃39;无法将lambda表达式转换为类型字符串，因为它不是委托类型。＆＃39;所以我必须使用DropDownList助手错误。

这是我的ViewModel：

public class AlternateCodeViewModel
{
    //public web2_item_alternate_code web2_item_alternate_code { get; set; }

    [Key]
    [Column(Order = 0)]
    public int inv_mast_uid { get; set; }

    [Key]
    [Column(Order = 1)]
    [StringLength(50)]
    [Display(Name = "Alternate Code")]
    public string Alternate_Code_Item_ID { get; set; }

    [Key]
    [Column(Order = 2)]
    public int Alternate_Code_Brand_ID { get; set; }

    [Required]
    [StringLength(1)]
    [Display(Name = "Exact Flag")]
    public string Exact_Flag { get; set; }

    [Required]
    [StringLength(1)]
    [Display(Name = "Delete Flag")]
    public string Delete_Flag { get; set; }

    public int item_brand_uid { get; set; }

    public IEnumerable<web2_item_brands> web2_item_brands { get; set; }
    public inv_mast inv_mast { get; set; }


}`

这是我的控制器：

这是我的观点：

<div class="form-group">
        @Html.LabelFor(model => model.web2_item_brands, "Brand Name", htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.DropDownListFor(model => model.web2_item_brands, Model.web2_item_brands, htmlAttributes: new { @class = "form-control" })
            @*@Html.ValidationMessageFor(model => model.web2_item_brands, "", new { @class = "text-danger" })*@
        </div>
    </div>

Answer 1

您必须将dropdownlist绑定到selectlistitems而不是其他复杂类型。这样的事情。

<强>模型

public class AlternateCodeViewModel
{
    [Key]
    [Column(Order = 0)]
    public int inv_mast_uid { get; set; }

    [Key]
    [Column(Order = 1)]
    [StringLength(50)]
    [Display(Name = "Alternate Code")]
    public string Alternate_Code_Item_ID { get; set; }

    [Key]
    [Column(Order = 2)]
    public int Alternate_Code_Brand_ID { get; set; }

    [Required]
    [StringLength(1)]
    [Display(Name = "Exact Flag")]
    public string Exact_Flag { get; set; }

    [Required]
    [StringLength(1)]
    [Display(Name = "Delete Flag")]
    public string Delete_Flag { get; set; }

    public int item_brand_uid { get; set; }

    public IEnumerable<web2_item_brands> web2_item_brands { get; set; }
    public inv_mast inv_mast { get; set; }

}

public class inv_mast
{

}

public class web2_item_brands
{
    public int item_brand_uid { get; set; }
    public string item_brand_text { get; set; }
}

控制器操作

public class HomeController : Controller
{
    public ActionResult Index()
    {
        return View(new AlternateCodeViewModel
        {
            web2_item_brands = 
                new[] 
                {new web2_item_brands 
                    { item_brand_text = "text", item_brand_uid = 1}
                }
        });
    }
}

标记代码

@using System.Web.Mvc.Html
@model Test.ViewModels.AlternateCodeViewModel

<div class="form-group">
    <div class="col-md-10">
        @Html.DropDownListFor(model => model.item_brand_uid, 
        Model.web2_item_brands.Select(s => 
            new SelectListItem { Value = s.item_brand_uid.ToString(), Text = s.item_brand_text}), 
        htmlAttributes: new { @class = "form-control" })
    </div>
</div>

注意：我不知道这个复杂类型web2_item_brands代表什么，因此我声明了一个上面同名的简单类，只是为了向您展示用法。

ASP.NET MVC 5：如何使用ViewModel中的IEnumumerble添加下拉列表？

1 个答案: