使用jquery将DataTable传递给Json

Question

我正在尝试执行一个Web服务,该服务使用以下代码返回DataTable:

$.ajax({  
    type: "POST",  
    url: url,  
    data: data,   
    contentType: "application/json; charset=utf-8",  
    dataType: "json",  
    success: function(msg) {  
        //do things  
        }  
    }); 

如果webservice返回一个类,那么它就可以工作,因此它与输入参数等无关.它只在web方法返回一个数据表时失败(数据表只有2列和2行用于我正在进行的测试).

WebService类使用[ScriptService]属性进行修饰,因此我认为ASP.NET会自动将返回值序列化为JSON.它似乎不适用于数据表.

我发现的唯一解决方案是返回一个字符串(一个手动JSON序列化对象),但这样做对我来说似乎不对.
我正在使用Visual Studio 2008和.Net 3.5

Answer 1

最后,我决定使用JavaScriptSerializer类将DataTable转换为JSON字符串.不幸的是,这个类不适用于DataTable,所以我将DataTable转换为dictionnaries列表并将该列表传递给JavaScriptSerializer类.它只需几行代码就可以正常工作.
VB.net中的示例:

    Public Function GetJson(ByVal dt As DataTable) As String

        Dim serializer As System.Web.Script.Serialization.JavaScriptSerializer = New System.Web.Script.Serialization.JavaScriptSerializer()
        Dim rows As New List(Of Dictionary(Of String, Object))
        Dim row As Dictionary(Of String, Object)

        For Each dr As DataRow In dt.Rows
            row = New Dictionary(Of String, Object)
            For Each col As DataColumn In dt.Columns
                row.Add(col.ColumnName, dr(col))
            Next
            rows.Add(row)
        Next
        Return serializer.Serialize(rows)
    End Function

Answer 2

最简单的方法是使用LINQ to DataSet扩展.首先需要使用LINQ to DataSet从DataTable创建一个通用列表(在这种情况下,SearchSerialResults只是一个DTO).

            var resultItems = (from DataRow dr in _returnedData.AsEnumerable()
                           select new SearchSerialResults
                           {
                               ContractLineItem = (int)dr["fldContractLineItemID"],
                               SearchItem = (string)dr["Search Item"],
                               Customer = (string)dr["Customer"],
                               DeviceFound = (string)dr["Device Found"],
                               Country = (string)dr["Country"],
                               City = (string)dr["City"],
                               ContractNumber = (string)dr["Contract Number"],
                               QuoteNumber = (string)dr["Quote Number"],
                               BeginDate = (string)dr["Begin Date"],
                               EndDate = (string)dr["End Date"]
                           }).ToList();

在这种情况下,_returnedData是DataTable.第2步是进行转换.在这种情况下,我为jqGrid返回一个Json对象.

var jsonObject = new
        {
            total = totalPages,
            pageSize,
            records = totalRecords,
            rows = (from SearchSerialResults item in resultItems
                    select new
                    {
                        id = item.ContractLineItem,
                        cell = new[]
                        {
                            item.ContractLineItem.ToString(), 
                            item.SearchItem,
                            item.DeviceFound,
                            item.Customer,
                            item.ContractNumber, 
                            item.QuoteNumber,
                            item.Country,
                            item.City,
                            item.BeginDate, 
                            item.EndDate,
                            ""
                        }
                    }).ToArray()
        }; 
return Json(jsonObject) // for MVC