how to get selected drow down list value in Action?

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隐瞒了意图╮
隐瞒了意图╮ 2021-01-27 10:02

In MVC web app it is a view with strongly typed model where a drop down is being generated / bind by model.

Below is view code:

@model LoanViewModel    
         


        
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  • 2021-01-27 10:43

    A simple example of using Html.DropDownFor() to display a list of options and bind to a property:

    Model

    public class LoanViewModel
    {
      [Required]
      [Display(Name="Select Item")]
      public string Item { get; set; }
    
      public SelectList ItemList { get; set; }
    }
    

    Controller

    public ActionResult Edit()
    {
      LoanViewModel model = new LoanViewModel();
      model.Item = "Two"; // this will now pre-select the second option in the view
      ConfigureEditModel(model);
      return View(model);
    }
    
    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Edit(LoanViewModel model)
    {
      if (!ModelState.IsValid)
      {
        ConfigureEditModel(model); // repopulate select list
        return View(model); // return the view to correct errors
      }
      // If you want to validate the the value is indeed one of the items
      ConfigureEditModel(model);
      if (!model.ItemList.Contains(model.Item))
      {
        ModelState.AddModelError(string.Empty, "I'm secure!");
        return View(model);
      }
    
      string selectedItem = model.Item;
      ....
      // save and redirect
    }
    
    private void ConfigureEditModel(LoanViewModel model)
    {
      List<string> items = new List<string>() { "One", "Two", "Three" };
      model.ItemList = new SelectList(items); // create the options
      // any other common stuff
    }
    

    View

    @model LoanViewModel
    @using (Html.BeginForm())
    {
      @Html.AntiForgeryToken()
      @Html.ValidationSummary(true)
    
      @Html.DisplayFor(m => m.Item)
      @Html.DropDownListFor(m => m.Item, Model.ItemList), "--Choose any Item--")
      @Html.ValidationMessageFor(m => m.Item)
    
      <input type="submit" value="Submit" />
    }
    
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