How to Set the Selected Value in @Html.DropDownListFor When the Value Is in an Array?

Use@html.dropdownListfor to set the medium value of the array in the asp.net MVC 5 in ASP.NET MVC 5

In the ASP.NET MVC 5 application, the auxiliary method can be used to generate a drop -down list from a data set. However, when processing complex data structures (such as array), setting the selection value according to the attributes in the array may bring challenges.

Consider the following ViewModel:

@Html.DropDownListFor()

How the challenge here is based on the selection value in the drop -down list according to the

attribute of the

object in the

@model MyProject.Web.API.Models.AggregationLevelConfViewModel

@Html.DropDownListFor(m => m.Configurations[0].HelperCodeType, (SelectList)Model.HelperCodeTypeItems, new { id = "Configurations[0].HelperCodeType" })

array.

The conventional method of setting the selection value in the constructor is invalid, because the selection value that is not available in the Configurations collection. AggregationLevelConfiguration HelperCodeType <决> Solution: SelectList HelperCodeTypeItems

<一> Method 1: Use the editor template

Create an editor template in <创>:

Then, in the main view, use to pass

to the editor template:

/Views/Shared/EditorTemplates/AggregationLevelConfiguration.cshtml

<二> Method 2: Generate new SELECTList

@model yourAssembly.AggregationLevelConfiguration
@Html.DropDownListFor(m => m.HelperCodeType, (SelectList)ViewData["CodeTypeItems"])

additionalViewData set <为> SelectList instead of

. Then, in the main view: <视>

@using (Html.BeginForm())
{
  ...
  @Html.EditorFor(m => m.Configurations , new { CodeTypeItems = Model.CodeTypeItems })
  ...
}

Please note that The attribute is automatically generated by without manual specification.

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