[英]How to set default value for ASP.NET MVC DropDownList from ViewBag
在控制器索引中,我有以下內容:
ViewBag.Assignees = (await GetAllUsers()).Select(a =>
new SelectListItem
{
Text = a.DisplayName,
Value = a.Username,
Selected = a.DisplayName == "John Smith"
}).OrderBy(x => x.Text).ToList();
在視圖中,我有以下內容:
@Html.DropDownListFor(model => model.Assignee,
ViewBag.Assignees as List<SelectListItem>,
"Select Assignee",
new { id = "ddlAssignee", @class = "form-control"})
下拉列表按預期填充,但是,確實存在的默認值 (selected = true) 未設置。 有人可以建議上面有什么問題嗎?
更新:
通過將SelectListItem.Value
更改為a.DisplayName
(與SelectedListItem.Text
相同),我實現了它。 仍然不確定是什么阻止下拉列表顯示Selected = true
的項目
如果model.Assignee
帶有值,如果它是一個 int 則默認為 0,它將覆蓋SelectListItem選擇的值。
我建議設置model.Assignee
。
Here two ways that i use.
WAY 1
@Html.DropDownListFor(model => model.Assignee,
ViewBag.Assignees as List<SelectListItem>,
"Value", // property to be set as Value of dropdown item
"Text", // property to be used as text of dropdown item
"1"), // value that should be set selected of dropdown
new { id = "ddlAssignee", @class = "form-control"})
WAY 2
<select name="SelectName" value="1" class="w-100">
@foreach (var item in ViewBag.Collection) {
<option value="@item.Id">@item.Name</option>
}
</select>
我希望它對你有用
在您的視圖集中:
@Html.DropDownListFor(model => model.Assignee,
ViewBag.Assignees as List<SelectListItem>,
"Select Assignee",
new { id = "ddlAssignee", @class = "form-control", @value = "Default value"})
當您已經定義了列表時。 用這個
@Html.DropDownList("CoverageDropDown", new SelectList(Model.youList, "Code", "Description",item.seletecItem), "Select")
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