Question

我是vb.Net的新手，我用Google搜索了这个，但没找到我要找的东西，我的情况是我使用ajax将json发布到http处理程序，json看起来像：

 [
  {Id:1, view,:true , write:false},
  {Id:2, view: true , write:true}, ..etc
 ]

发布部分工作正常，但我仍然坚持如何访问httphandler中的tree_data以及如何获取tree_data参数的所有属性的值。通常我会以这种方式访问发布的值：

 Dim tree_data = context.Request("tree_data") \\ This Returning Nothing here, I think this way is used when the data type is not json

我的Ajax代码：

     var tree_data = getTreeData();
       // alert(tree_data.length);
        $.ajax({
            url: "Profiles_SubmitPermissions.ashx",
            type: "POST",
            data: JSON.stringify(tree_data),
            async: false,
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            error: function (xhr, status, error) {
                alert(error)
            }
        }).done(function (data) {
            CreateTree('ACTMNG');
        });

http Handler中的代码：

Imports System.Web
Imports System.Web.Services
Imports System.Web.Script.Serialization

Public Class Profiles_SubmitPermissions
Implements System.Web.IHttpHandler

Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest

    context.Response.ContentType = "text/plain"
    context.Response.Write("Hello World!")

    Dim jsonSerializer As System.Web.Script.Serialization.JavaScriptSerializer = New System.Web.Script.Serialization.JavaScriptSerializer()
    Dim connectionString As String = UserIdentity.ClientConfig.ConnectionString
    'Get parameters                
    'I need to get access to tree_data json
    'I need to access to json properties such as id, view , write


End Sub

ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
    Get
        Return False
    End Get
End Property

End Class

Answer 1

C＃Answer建议人@N0Alias非常有帮助，

Vb.Net版本是：

导入的库：

  Imports System.Web.Script.Serialization
  Imports System.IO

将从请求中获取json的部分代码：

   Dim tree_data As String = Nothing
    HttpContext.Current.Request.InputStream.Position = 0
    Using inputStream As StreamReader = New StreamReader(HttpContext.Current.Request.InputStream)
        tree_data = inputStream.ReadToEnd()
    End Using

Dim jsonSerializer As System.Web.Script.Serialization.JavaScriptSerializer = 
New System.Web.Script.Serialization.JavaScriptSerializer()

    Dim permissions = jsonSerializer.Deserialize(Of List(Of Object))(tree_data)

解析json以提取值的部分代码，可能是这段代码可以用不同的方式编写，但这就是我使用的：

     For Each obj In permissions 
            Dim id As Integer
            Dim view As Boolean
            Dim write As Boolean
             For Each pair In obj // each object is a pair of key and value
                If pair.Key.Equals("Id") Then
                   id = pair.Value
                ElseIf pair.Key.Equals("view") Then
                   view = pair.Value
                ElseIf pair.Key.Equals("write") Then
                   write = pair.Value
                End If

             Next
           // Do something with the current id , view ,write parameters
     Next

如何在vb.net中访问和解析发布的json

1 个答案: