选择mvc 4下拉默认值
我想在下拉列表中选择默认值,其中policyId = 7但它没有选择该值,我做错了什么?
控制器:
var pm = new ManagerClass(); IEnumerable po = pm.GetDataFromDb(); IEnumerable Policies = new SelectList(po, "PolicyID", "PolicyName", new { PolicyID = 7 }); ViewBag.Policies = Policies;
视图:
@Html.DropDownListFor(m => m.PolicyID, ViewBag.Policies as IEnumerable, new { @class = "dropdown-field"})
只需将视图模型上的PolicyID
属性设置为您要预选的值:
var pm = new ManagerClass(); var po = pm.GetDataFromDb(); ViewBag.Policies = new SelectList(po, "PolicyID", "PolicyName"); viewModel.PolicyID = 7; return View(viewModel);
由于DropDownList绑定到PolicyID
属性( m => m.PolicyID
),因此在决定要预选哪个元素时将使用其值。
这是因为它实际上并没有选择SelectList
的值。
首先,为了使它更好,将项目放在视图模型中以防止强制转换(这也是更好的做法):
public class MyModel { public int PolicyID { get; set; } public List Policies { get; set; } //rest of your model }
然后填充它:
var model = new MyModel(); model.Policies = po .Select(p => new SelectListItem { Text = p.PolicyName, Value = p.PolicyID.ToString(), Selected = p.PolicyID == currentPolicyId //change that to whatever current is }) .ToList();
然后在你看来,做:
@Html.DropDownListFor(m => m.PolicyID, Model.Policies, new { @class = "dropdown-field"})
这是DropDownList:
控制器:
List FieldListItems = new List();
FieldListItems.Add(new SelectListItem {Text =“Project ID”,Value =“Project_ID”});
FieldListItems.Add(new SelectListItem {Text =“Project Name”,Value =“Project_Name”});
ViewBag.SearchByList = new SelectList(FieldListItems,“Value”,“Text”,selectedValue:Project_ID);
风景:
排序方式:@ Html.DropDownList(“sortOrder”,(SelectList)ViewBag.SortingByList)
您可以将控制器中的selectedValue更改为您想要的项目作为默认值
如果你有一个静态菜单:
1-创建以下类:
public static class StaticMenus { public static List GetGridRowsCount() { List result = new List (); result.Add("3"); result.Add("5"); result.Add("10"); result.Add("20"); result.Add("25"); result.Add("50"); result.Add("100"); return result; } }
2-将以下代码添加到您的控制器:
ViewData["CountryList"] = new SelectList(StaticMenus.GetGridRowsCount(),"10");
3-将以下代码添加到您的视图中:
@Html.DropDownList("MainGridRowsCount", ViewData["RowsCountList"] as SelectList)