How to Set Selected Value in MVC5 Razor `Html.DropDownListFor` when Value is in an Array?

Setting Selected Values in MVC5 Razor Html.DropDownListFor with Array Values

Working with arrays and @Html.DropDownListFor() in ASP.NET MVC 5 to select values can be tricky. Here are two approaches to overcome this challenge:

Method 1: Leveraging EditorTemplates

This method involves creating a dedicated EditorTemplate for the collection's data type. The SelectList is then passed to the EditorTemplate as additional ViewData.

// AggregationLevelConfiguration.cshtml (EditorTemplate)
@Html.DropDownListFor(m => m.HelperCodeType, (SelectList)ViewData["CodeTypeItems"])

// Main View
@Html.EditorFor(m => m.Configurations, new { CodeTypeItems = Model.CodeTypeItems })

This approach cleanly separates the dropdown logic from the main view, improving maintainability.

Method 2: Dynamic SelectList Generation

Alternatively, you can replace IEnumerable properties with IEnumerable<GenericIdNameType> (replace GenericIdNameType with your actual type). Then, iterate through the array in your main view, creating a new SelectList for each item and setting the selected value accordingly.

// Main View
@for (int i = 0; i < Model.Configurations.Count(); i++)
{
    @Html.DropDownListFor(m => m.Configurations[i].HelperCodeType, 
                           new SelectList(Model.CodeTypeItems, "Id", "Name", Model.Configurations[i].HelperCodeType))
}

This method is more direct but can become less manageable with larger arrays. Consider using a helper method to encapsulate the SelectList creation for better readability if you choose this approach. Remember to adjust "Id" and "Name" to match your actual properties.

The above is the detailed content of How to Set Selected Value in MVC5 Razor `Html.DropDownListFor` when Value is in an Array?. For more information, please follow other related articles on the PHP Chinese website!