预选下拉列表剃须刀页面

Question

I have the below code that I use to populate my dropdown in my Razor Page I want to preselect a description - the "Value" of that needs to be set is found in

s.UserEstablishmentId

How can I preselect this on the dropdown

@Html.DropDownList("drpEstablishments",
                    getEstablishments().Select(s => new SelectListItem()
                        {

                          Text = s.Description,
                          Value = s.EstablishId.ToString()
                      }),
                     new
                     {
                         @class = "dropdown form-control"
                     })

Answer 1

You're using linq to create a new SelectListItem for getEstablishments element. When creating each instance of a SelectListItem() you need to determine if Selected should be true or false . Simply replace YourConditionForSelectionHere with a method that returns a bool or syntax that returns a bool , shown below:

@Html.DropDownList("drpEstablishments",
                    getEstablishments().Select(s => new SelectListItem()
                        {
                          Selected = (YourConditionForSelectionHere),
                          Text = s.Description,
                          Value = s.EstablishId.ToString()
                      }),
                     new
                     {
                         @class = "dropdown form-control"
                     })

Answer 2

最后像这样的事情

 Selected= (s.UserEstablishmentId==s.EstablishId)? true:false,