How do I get the Selected Value of a DropDownList in ASP.NET Core MVC App - asp.net-core

Question

I have the following dropdownlist in my view:
#{
var listado = new List<SelectListItem>()
{
new SelectListItem()
{
Text ="YES",
Value ="1"
},
new SelectListItem()
{
Text = "NO",
Value = "2"
}
};
}
<div class="form-group">
<label class="control-label">Is it True ?</label>
#Html.DropDownList("miDropDownList",listado)
</div>
I want to get the selected value 'YES' or 'NO' to do something in the controller like so:
IActionResult ControllerAction(){
var theValue = dropdownList.SelectedValue //this is pseudocode syntax but you understand I want to get
//the value
// with the value I will do something like this:
User userinstance = new User {
Id = 1,
Name = "john",
isJohnTall = theValue.Value
}
}
I want something simple in other answers I've seen DropDownLists that are bound to models, but I just want to get strings selected in the dropdown and be able to do something with them in the controller.

Answer 1

You can use JQuery with ajax.
Something like this:
<div class="form-group">
<label class="control-label">Is it True ?</label>
#Html.DropDownList("miDropDownList", listado, new { #onchange = "GetYesOrNo()"})
</div>
<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script>
function GetYesOrNo() {
var selectElement = document.querySelector('#miDropDownList');
var option = selectElement.value;
$.ajax({
url: '/Home/GetYesOrNo',
type: 'GET',
dataType: 'json',
contentType: 'application/json; charset=utf-8',
mimeType: 'text/html',
data: { getOption : option },
success: function (returnValue) {
alert(returnValue);
}
});
};
</script>
And in Home Controller, add this JsonResult:
public JsonResult GetYesOrNo(int getOption)
{
if (getOption == 1) return Json("Option: YES");
return Json("Option: NO");
}

Answer 2

You can use a form to submit your data.
The form will submit Value, so you can modify your value as Text.
You can change your code like below.
View:
#{
var listado = new List<SelectListItem>()
{
new SelectListItem()
{
Text ="YES",
Value ="YES"
},
new SelectListItem()
{
Text = "NO",
Value = "NO"
}
};
}
#using (Html.BeginForm("GetYesOrNo", "User"))
{
<div class="form-group">
<label class="control-label">Is it True ?</label>
#Html.DropDownList("miDropDownList", listado)
</div>
<button type="submit">Find</button>
}
Action:
public IActionResult GetYesOrNo(string miDropDownList)
{
//.....
return View();
}
Test result:
And how to bind to the model with dropdownlist,you can see my this reply,it may helpful.