Question

我已经完成了一系列教程来实现这个目标，但没有一个对我有用。我在下面的链接中偶然发现了教程，并将其转换为我的VB.Net用法，并且这是唯一一个曾回复过但有错误的人：[object Object]。不知道如何解决这个问题，有人可以帮忙吗？

https://www.c-sharpcorner.com/UploadFile/4d9083/creating-simple-cascading-dropdownlist-in-mvc-4-using-razor/

以下是我的代码：

控制器

Public Function PullStates(ByVal id As Integer) As JsonResult  

    Dim states = db.States.Where(Function(s) s.CountryCode = id).[Select](Function(s) New With   
    {  
        Key .Text = s.Descrip,   
        Key .Value = s.Code  
    })  
    Return Json(New SelectList(states, "Value", "Text"))  

End Function  

'GET: Region/Create  
Function Create() As ActionResult  
    ViewBag.Code = "AUTO"  


    ViewBag.Country = db.Countries.[Select](Function(c) New SelectListItem With  
    {  
        .Text = c.Descrip,  
        .Value = c.CountryCode  
    })  


    Return View()  
End Function

查看

@Html.DropDownList("Country", CType(ViewBag.Country, IEnumerable(Of SelectListItem)), "--Select Country--", htmlAttributes:=New With {.class = "tb8"}) 
@Html.DropDownList("State", New SelectList(String.Empty, "Value", "Text"), "--Please Select State--", htmlAttributes:=New With {.class = "tb8"})

脚本

<!-- language: lang-js -->

    <script src="~/Scripts/ddl/jquery-1.7.1.js" type="text/javascript"></script>  
    <script src="~/Scripts/ddl/jquery-1.7.1.min.js" type="text/javascript"></script>  
    <script type="text/javascript">  
    $(document).ready(function () {  
            //Dropdownlist Selectedchange event  
            $("#Country").change(function () {  
                $("#State").empty();  
                $.ajax({  
                    type: 'POST',  
                    url: '@Url.Action("PullStates")', // we are calling json method  
                    dataType: 'json',  
                    data: { id: $("#Country").val() },  
                    success: function (states) {  
                        // states contains the JSON formatted list  
                        // of states passed from the controller  
                        $.each(states, function (i, state) {  
                            $("#State").append('<option value="' + state.Value + '">' + state.Text + '</option>');  
                        }); // here we are adding option for States  
                    },  
                    error: function (ex) {  
                        alert('Failed to retrieve states.' + ex);  
                    }  
                });  
                return false;  
            })  
        });  
    </script>   

<!-- end snippet -->

Answer 1

我不知道vb.net但在这里你不需要将变量更改为选择列表jsut直接传递这样

Public Function PullStates(ByVal id As Integer) As JsonResult  

        Dim states = db.States.Where(Function(s) s.CountryCode = id).[Select](Function(s) New With   
       {  
        Key .Text = s.Descrip,   
        Key .Value = s.Code  
        })  
        Return Json(states)

尝试像这样改变你的ajax成功函数

 success: function (data) {   
                  $(data).each(function(){
                        $("#State").append('<option value="' + this.Value + '">' + this.Text + '</option>');  
                    }); 
                },

如何根据另一个下拉列表MVC（VB.Net）获取下拉列表

1 个答案: