如何设置一个选择元素的项目索引为-1? [英] How can I set a select element's itemindex to -1?
问题描述
我动态地添加值到选择的元素在我看来,code,像这样在我看来/ .cshtml:
@model WebAppRptScheduler.Models.HomeModel
@using System.Data这
@ {
数据表dtUnits = Model.Units的数据表;
变种单元从X =在dtUnits.AsEnumerable()
新选择
{
单位= x.Field<串GT(单位)
};
.....
<选择类=形式的控制,下拉NAME =unitsselect>
@foreach(以单位VAR场)
{
<选项ID =selItem _ @(field.unit)VALUE =@ field.unit> @ field.unit< /选项>
}
< /选择>
.....
中的值填充罚款,但被自动被选中在选择元素中的第一个选项。我怎么可以设置它,以便没有选定为-1?我能做到这一点上面的foreach循环之后,或者使用JavaScript它,我必须做的,或者我可以做到这一点在C#code隐藏文件?
这样的:
<选择类=形式的控制,下拉NAME =unitsselect>
<选项禁用所选值> - 选择一个选项 - < /选项>
@foreach(以单位VAR场)
{
<选项ID =selItem _ @(field.unit)VALUE =@ field.unit> @ field.unit< /选项>
}
< /选择>
- 选择一个选项 -
将被默认显示。但是,如果你选择一个选项,你将无法选择它回来
块引用>来源:默认选择选项为空白
I'm dynamically adding values to a select element in my View code like so in my View/.cshtml:
@model WebAppRptScheduler.Models.HomeModel @using System.Data @{ DataTable dtUnits = Model.Units as DataTable; var units = from x in dtUnits.AsEnumerable() select new { unit = x.Field<string>("unit") }; ..... <select class="form-control, dropdown" name="unitsselect"> @foreach (var field in units) { <option id="selItem_@(field.unit)" value="@field.unit">@field.unit</option> } </select> .....
The values are populating fine, but the first option in the select element is automatically being selected. How can I set it to -1 so that nothing is selected? Can I do it after the foreach loop above, or must I do it using javascript, or can I do it in a C# code-behind file?
解决方案Like this :
<select class="form-control, dropdown" name="unitsselect"> <option disabled selected value> -- select an option -- </option> @foreach (var field in units) { <option id="selItem_@(field.unit)" value="@field.unit">@field.unit</option> } </select>
-- select an option --
Will be displayed by default. But if you choose an option,you will not be able select it backSource : default select option as blank
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