I want to create an empty dropdown list that has just default value.I use the following code:
@Html.DropDownList("parent","--Select Parent--")
But in running time I see this error:
There is no ViewData item of type 'IEnumerable' that has the key 'parent'.
How can I solve it? Thanks.
You can build an empty DropDownList like this:
@Html.DropDownList("parent", Enumerable.Empty<SelectListItem>(), "--Select Parent--")
Reference: Build an empty MVC DropdownListFor for a Cascade Sub-List
Adding html attributes to the above example:
@Html.DropDownList("Idparent", Enumerable.Empty<SelectListItem>(), "Select one...", new {@class="form-control"})
You may simply create an HTML Select option in your view.
<select id="parent" name="parent">
<option value="">Select parent </option>
</select>
EDIT : As per the comment.
When you submit the form, You can get the selected value by either having a parameter with parent name
[HttpPost]
public ActionResult Create(string parent,string otherParameterName)
{
//read and save and return / redirect
}
OR have a parent property in your ViewModel which you are using for Model binding.
public class CreateProject
{
public string parent { set;get;}
public string ProjectName { set;get;}
}
and in your action method.
[HttpPost]
public ActionResult Create(CreateProject model)
{
// check model.parent value.
}
HttpPost action, you can use a parent parameter or have a parent property in your viewmodel.You can do something like this in your controller to build a empty dropdown list
ViewBag.ClassID = new SelectList(db.Classes.Where(c => c.ClassID == 0) , "ClassID", "ClassName").ToList();
@Html.DropDownList(null, "--Select Parent--").