Question

我正在尝试在我的asp.net mvc应用程序中显示下拉列表。我在设置优先级中的列表项时遇到了困难。这里我的错误是什么？

public IList<SelectListItem> Priorities { get; set; }
Priorities = new List<SelectListItem>();
Priorities.Add(new IList<SelectListItem>
                {
                    new SelectListItem { Text = "High", Value = "1"},
                    new SelectListItem { Text = "Low", Value = "0"}
                });

@Html.DropDownListFor(m => m.SelectedPriority, Model.Priorities, "Select one")

Answer 1

尝试更改

Priorities = new List<SelectListItem>();

通过

Priorities = new List<SelectListItem>() {
                new SelectListItem { Text = "High", Value = "1"},
                new SelectListItem { Text = "Low", Value = "0"}
            };

或Cast和AddRange

 ((List<SelectListItem>)Priorities).AddRange(
                new List<SelectListItem>() {
                    new SelectListItem { Text = "High", Value = "1"},
                    new SelectListItem { Text = "Low", Value = "0"}
                }

            );

使用IEnumerable的其他选项：

public IEnumerable<SelectListItem> Priorities { get; set; }
Priorities = new List<SelectListItem>();

Priorities = Priorities.Concat(new List<SelectListItem>() {
                new SelectListItem { Text = "High", Value = "1"},
                new SelectListItem { Text = "Low", Value = "0"}
                }
        );

Answer 2

您无法在此处实例化界面：

Priorities.Add(new IList<SelectListItem>
{
    new SelectListItem { Text = "High", Value = "1"},
    new SelectListItem { Text = "Low", Value = "0"}
});

而是尝试将其实例化为实现IList的东西，并使用AddRangewhich用于这种情况：

Priorities.AddRange(new List<SelectListItem>
{
  new SelectListItem { Text = "High", Value = "1"},
  new SelectListItem { Text = "Low", Value = "0"}
});

Asp.Net MVC DropDownList问题

2 个答案: