asp.net - VB.Net SQL 结果为 Ajax 的 JSON

Question

新程序员，我正在使用 VB.Net 代码构建一个 aspx 页面，我正在尝试使用我们数据库中的数据创建一个 D3 图表，但我无法将返回值转换为正确的格式。

在我的 VB 代码中，我可以将字符串转换为我想要的确切格式:

[{ name: "PROAIR", value: 7}],{ name: "NASONEX", value: 4}] 

但是当我把它传回去时，结果是:

{"d":"[{name: \"PROAIR\", value: 7},{name: \"NASONEX\", value: 4}]"}

我知道(现在)它正在尝试序列化返回值，所以我尝试使用数据表并序列化它，然后使用 List(Of Object) 并序列化它，但每次我得到不同的结果时，更多的引号和转义退格返回值。我已经查看了 Microsoft Person 示例和一些 Stack Contacts 示例，但是我真的有必要构建一个全新的类并向其中添加新项目吗？
我的字符串生成器代码如下:

Dim sData As String
Dim sqlCmd As New SqlCommand(strSql, cn)
Using sdr As SqlDataReader = sqlCmd.ExecuteReader()
  Dim sb As New StringBuilder()
  sb.Append("[")
  While sdr.Read()
    sb.Append("{")
    System.Threading.Thread.Sleep(50)
    sb.Append(String.Format("name: '{0}', value: {1}", sdr(0), sdr(1)))
    sb.Append("},")
  End While
  sb = sb.Remove(sb.Length - 1, 1)
  sb.Append("]")
  sData = sb.ToString
  sData = sData.Replace("'", ControlChars.Quote)
  cn.Close()

  Return sData
End Using

如果我尝试序列化该字符串:

Dim serializer As New JavaScriptSerializer()
Dim SerializedResult = serializer.Serialize(sData)
Return SerializedResult 

我最终得到:{"d":"\"[{name: \\\"PROAIR\\\", value: 7},{name: \\\"NASONEX\\\", value: 4}]\""}
我试图反序列化它
Dim deserializedResult = serializer.Deserialize(Of String)(sData)
但它因数组类型失败而出错，所以显然你不能这样做:)

在 aspx 页面中，我进行了硬编码:

success: function (r) {
var data = [{ name: "PROAIR", value: 7}],{ name: "NASONEX", value: 4}]

我的图表构建完美，所以只需以正确的格式返回 sql 数据并将脚本代码更改为 var data = r;

编辑 工作代码如下:

aspx页面:

    $(function () {
        GetData();
    });

    function GetData() {
        $.ajax({
            type: "post",
            url: "D3PieChart.aspx/GetData",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (r) {

                data = r.d;
                data = jQuery.parseJSON(data)

-- Build D3 chart commands in this section --

            },
            error: function (xhr, status, error) {
                OnFailure(error);
                alert('Error');
            }
        });
   }

</script>

VB页面:

<WebMethod()> _
Public Shared Function GetData() As String     

    Dim sConnect As String = ConfigurationManager.ConnectionStrings("SQLConnectionString").ConnectionString
    Dim cn As New SqlConnection(sConnect)
Dim strSql As String = "SELECT name and a count of stuff "
strSql += "FROM a bunch of tables WHERE stuff = stuff "

    Dim dtb As New DataTable
    cn.Open()
    If (cn.State And ConnectionState.Open) <> 0 Then
        Dim sqlCmd As New SqlCommand(strSql, cn)
        Dim sqlDad As New SqlDataAdapter(sqlCmd)
        sqlDad.Fill(dtb)
        dtb.Columns(0).ColumnName = "Name"
        dtb.Columns(1).ColumnName = "value"
        Dim sjData As String = GetJson(dtb)
        Return sjData
    End If
    Return -1
End Function



Public Shared Function GetJson(ByVal dt As DataTable) As String
    Dim serializer As New System.Web.Script.Serialization.JavaScriptSerializer()
    serializer.MaxJsonLength = Integer.MaxValue

    Dim rows As New List(Of Dictionary(Of String, Object))()
    Dim row As Dictionary(Of String, Object) = Nothing
    Dim row2 As Dictionary(Of Integer, Object) = Nothing
    For Each dr As DataRow In dt.Rows
        row = New Dictionary(Of String, Object)()
        row2 = New Dictionary(Of Integer, Object)()
        For Each dc As DataColumn In dt.Columns
            row.Add(dc.ColumnName.Trim(), dr(dc))
        Next
        rows.Add(row)
    Next
    Return serializer.Serialize(rows)
End Function
End Class

这是一个简单的图表，它不接受任何硬编码的参数，但它从 SQL Server 数据库中提取图表数据。

Answer 1

在数据表中获取您的 Sql 结果，并将其简单地传递给 GetJson 方法以获取 json 字符串。

Dim da As New OleDb.OleDbDataAdapter(strSql, cn)
Dim dt As DataTable = New DataTable
da.Fill(dt)

Dim sData As string = GetJson(dt)



 Public Shared Function GetJson(ByVal dt As DataTable) As String
        Dim serializer As New System.Web.Script.Serialization.JavaScriptSerializer()
        serializer.MaxJsonLength = Integer.MaxValue

        Dim rows As New List(Of Dictionary(Of String, Object))()
        Dim row As Dictionary(Of String, Object) = Nothing
        For Each dr As DataRow In dt.Rows
            row = New Dictionary(Of String, Object)()
            For Each dc As DataColumn In dt.Columns

                row.Add(dc.ColumnName.Trim(), dr(dc))

            Next
            rows.Add(row)
        Next
        Return serializer.Serialize(rows)
    End Function

添加 System.Collections.Generic 的引用

在aspx页面

success: function (r) {
var data = r.d;