Asp.net mvc dropdown list using ViewBag

问题:

My table in db have fields : Id,Organisation,Info.

I want make dropdowm list like that:

<select>
  <option value='Id there'>'Organisation there'</option>...

I'm try to do it, using ViewBag:

ViewBag.Organisations = db.Organisations.ToList(); // get all fields from table using dbContext

and in View:

@Html.DropDownList('I don`t know what i shoud write here, please help')

How i can build dropdown list?

回答1:

You would need to create a SelectList in controller action using one of the constructors available and in view just pass it DropDownList method as parameter.

In Controller do this:

ViewBag.Organisations = new SelectList(db.Organisations.ToList(),"Id","Organisation");

in SelectList we need to specify which property to use as value and which to use as text in the option tag which we are specifying in last two parameters.

and then in View you would need to use it this way:

@Html.DropDownList("Organization",ViewBag.Organisations as SelectList)

Here first parameter would be used as name of select element and second one will be used to populate the option elements in the select

Following is the list of overloads available for Html.DropDownList :

https://msdn.microsoft.com/en-us/library/system.web.webpages.html.htmlhelper.dropdownlist%28v=vs.111%29.aspx?f=255&MSPPError=-2147217396

回答2:

I recommend you to define a ViewModel for your page with a OrganisationId property. Thus this value will be filled when selecting an entry of the organisations dropdown list.

@model BCO.Models.SelectOrganisationViewModel

@{
    ViewBag.Title = "OrganisationInfo";
}

<div>
    @Html.DropDownListFor(o => o.OrganisationId,
        new SelectList(ViewBag.Organisations, "Id", "Name"))
</div>

The SelectList itself expects

• the list to fill the DropDownList with
• the value ("Id")
• the text ("Name")

as parameters.

回答3:

You can use selectlist from viewbag as follows

@Html.DropDownListFor(m => m.Name, ViewBag.GetData as SelectList, new { @class = "form-control" })

here ViewBag.GetData is populated from the controller, the controller code should be like

ViewBag.GetData = new SelectList(repository.GetOrganisation(), "ID", "OraganizationName");