我只是想向此列表添加默认值(“创建新 field ”),这可能比我做的要容易。我对方法重载感到困惑,特别是因为我使用的重载(由脚手架创建)是 DropDownList(string name, IEnumerable selectList, object htmlAttributes) 并且第二个参数为 null,但它有效。我认为这里有一些惯例在起作用。谁能阐明这一点和/或我如何向此列表添加默认值?
Controller :
ViewBag.VenueId = new SelectList(db.Venues, "Id", "Name", review.VenueId);
return View(review);
}
查看:
<div class="form-group">
@Html.LabelFor(model => model.VenueId, "VenueId", htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("VenueId", null, htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.VenueId, "", new { @class = "text-danger" })
<div>Don't see what you're looking for? Fear not. Just type in the name and create your review; we'll fill in the rest!</div>
</div>
</div>
最佳答案
也许您可以分解您的 SelectList 并向其中插入一个项目?这是一个示例(尚未测试过,所以不能 100% 确定它有效):
Controller
// Create item list from your predefined elements
List<SelectListItem> yourDropDownItems = new SelectList(db.Venues, "Id", "Name", review.VenueId).ToList();
// Create item to add to list
SelectListItem additionalItem = new SelectListItem { Text = "Create new Venue", Value = "0" }; // I'm just making it zero, in case you want to be able to identify it in your post later
// Specify index where you would like to add your item within the list
int ddIndex = yourDropDownItems.Count(); // Could be 0, or place at end of your list?
// Add item at specified location
yourDropDownItems.Insert(ddIndex, additionalItem);
// Send your list to the view
ViewBag.DropDownList = yourDropDownItems;
return View(review);
查看
@Html.LabelFor(model => model.VenueId, new { @class = "form-control" })
<div>
@Html.DropDownListFor(model => model.VenueId, ViewBag.DropDownList)
@Html.ValidationMessageFor(model => model.VenueId)
</div>
</div>
编辑:
添加默认值的一种方法是在 .DropDownListFor 的最后一个参数中,如下所示:
@Html.DropDownListFor(model => model.VenueId, ViewBag.DropDownList, "Create new Venue")
关于c# - Html.DropDownList 默认值 MVC 5,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25943189/