jquery - 调用函数时服务器端数据表 ajax 返回“数据表警告：表 id=tblDataTable - 无效的 JSON 响应。”

Question

我有一个DataTableResponse.vb具有以下结构的类：

Public Class DataTableResponse
     Public draw As Integer
     Public recordsTotal As Integer
     Public recordsFiltered As Integer
     Public data As List(Of Restaurant)
End Class

在我的 aspx 页面中，我的服务器端数据表使用存储过程（method.GetData 采用 5 个参数）从 db 获取餐馆列表，以及我的 aspx 中的 ajaxDraw、OffsetValue、PagingSize、SearchBy、sortcolumn、sortDirection 等一些其他数据表属性用户选择的页面。

        $(document).ready(function () {
            //Once the document is ready call Bind DataTable
            BindDataTable();
        });

        function BindDataTable() {
            var mytable = $('#tblDataTable').DataTable({
                "processing": true,
                "serverSide": true,
                //"dataSrc": "",
                "ajax": {
                    url: "adminrestaurants.aspx/GetDataForDataTable", type: "post"
                },
                "columns": [
                    {
                        "data": "Title",
                    },
                    {
                        "data": "colorActive",
                        "render": function (data, type, row) { return "<i class='fa fa-fw fa-circle' style= color:" + data + "></i>" }
                    },
                    {
                        data: null,
                        className: "center",
                        defaultContent: '<a href="" class="edit btn btn-link">Edit</a>'
                    },
                    {
                        data: null,
                        className: "center",
                        defaultContent: '<a href="" class="view btn btn-link">View</a>'
                    },
                    {
                        data: null,
                        className: "center",
                        defaultContent: '<a href="" class="MenuImage btn btn-link"><i class="fas fa-utensils"></i></a>'
                    },
                    {
                        data: null,
                        className: "center",
                        defaultContent: '<a href="" class="RestImage btn btn-link"><i class="fa fa-image"></i></a>'
                    },
                    {
                        data: null,
                        className: "center",
                        defaultContent: '<a id="btn-delete" href="" class="delete btn btn-link"><i class="fa fa-trash"></i></a>'
                    },
                ],
                'columnDefs': [{
                    'targets': [2, 3, 4, 5, 6], /* column index */
                    'orderable': false, /* true or false */
                }],
                rowId: 'Id',

                "initComplete": function (settings, json) {
                    addDiv();
                },

            });

当我调用 Web 服务（asmx）类时，一切正常，但是我决定将 Web 服务转换为私有函数，如下所示：

<System.Web.Services.WebMethod()>
Public Shared Function GetDataForDataTable() As String
    Dim method As New methods
    Dim context As HttpContext = HttpContext.Current
    context.Response.ContentType = "text/plain"
    Dim columns As List(Of String) = New List(Of String)()
    columns.Add("Title")
    columns.Add("IsActive")
    columns.Add("Edit")
    columns.Add("View")
    columns.Add("RestImages")
    columns.Add("MenuImages")
    columns.Add("delete")
    Dim ajaxDraw As Int32 = Convert.ToInt32(context.Request.Form("draw"))
    Dim OffsetValue As Int32 = Convert.ToInt32(context.Request.Form("start"))
    Dim PagingSize As Int32 = Convert.ToInt32(context.Request.Form("length"))
    Dim searchby As String = context.Request.Form("search[value]")
    Dim sortColumn As String = context.Request.Form("order[0][column]")
    sortColumn = "r." & columns(Convert.ToInt32(sortColumn))
    Dim sortDirection As String = context.Request.Form("order[0][dir]")
    Dim dt As DataTable = method.GetData(sortColumn, sortDirection, OffsetValue, PagingSize, searchby)
    Dim recordTotal As Int32 = 0
    Dim restaurants As List(Of Restaurant) = New List(Of Restaurant)()

    If dt IsNot Nothing Then

        For i As Integer = 0 To dt.Rows.Count - 1
            Dim restaurant As Restaurant = New Restaurant()
            restaurant.Id = If(Convert.IsDBNull(dt.Rows(i)("RID")), Nothing, Convert.ToInt32(dt.Rows(i)("RID")))
            restaurant.Title = If(Convert.IsDBNull(dt.Rows(i)("Rtitle")), Nothing, Convert.ToString(dt.Rows(i)("Rtitle")))
            restaurant.IsActive = If(Convert.IsDBNull(dt.Rows(i)("Ractive")), Nothing, Convert.ToInt32(dt.Rows(i)("Ractive")))
            restaurant.colorActive = dt.Rows(i)("activeColor")
            restaurants.Add(restaurant)
        Next

        recordTotal = If(dt.Rows.Count > 0, Convert.ToInt32(dt.Rows(0)("FilterTotalCount")), 0)
    End If

    Dim recordFiltered As Int32 = recordTotal
    Dim objDataTableResponse As DataTableResponse = New DataTableResponse() With {
        .draw = ajaxDraw,
        .recordsFiltered = recordTotal,
        .recordsTotal = recordTotal,
        .data = restaurants
    }

    Return Newtonsoft.Json.JsonConvert.SerializeObject(objDataTableResponse.ToString)
End Function

我在页面加载时遇到以下错误 -> '**DataTables 警告：表 id=tblDataTable - JSON 响应无效。有关此错误的更多信息，请参阅http://datatables.net/tn/1**'。

任何帮助深表感谢。

标签： jqueryjsonweb-servicesasp.net-ajaxserverside-datatable