Flex 一周视频培训系列学习笔记(一)

使用Http Service 获取数据

先用asp.net mvc构建数据源.

这个是作了修改的MvcContrib下的XmlResult代码.用来返回Northwind 数据库下的Employee数据.格式为xml

using System.Web.Mvc;
using System.Xml.Serialization;
using System.Data;
namespace MvcContrib.ActionResults
{
    /// <summary>
    /// Action result that serializes the specified object into XML and outputs it to the response stream.
    /// <example>
    /// <![CDATA[
    /// public XmlResult AsXml() {
    ///        List<Person> people = _peopleService.GetPeople();
    ///        return new XmlResult(people);
    /// }
    /// ]]>
    /// </example>
    /// </summary>
    public class XmlResult : ActionResult
    {
        private object _objectToSerialize;
        private ObjectType _type;
        /// <summary>
        /// Creates a new instance of the XmlResult class.
        /// </summary>
        /// <param name="objectToSerialize">The object to serialize to XML.</param>
        public XmlResult(object objectToSerialize)
        {
            _objectToSerialize = objectToSerialize;
            _type = ObjectType.Object;
        }
        public XmlResult(object objectToSerialize, ObjectType type)
        {
            _objectToSerialize = objectToSerialize;
            _type = type;
        }
        /// <summary>
        /// The object to be serialized to XML.
        /// </summary>
        public object ObjectToSerialize
        {
            get { return _objectToSerialize; }
        }

        /// <summary>
        /// Serialises the object that was passed into the constructor to XML and writes the corresponding XML to the result stream.
        /// </summary>
        /// <param name="context">The controller context for the current request.</param>
        public override void ExecuteResult(ControllerContext context)
        {
            if (_objectToSerialize != null)
            {
                context.HttpContext.Response.ContentType = "text/xml";
                switch (_type)
                {
                    case ObjectType.DataSet:
                        DataSet ds = _objectToSerialize as DataSet;
                        ds.WriteXml(context.HttpContext.Response.OutputStream);
                        break;
                    case ObjectType.DataTable:
                        DataTable dt = _objectToSerialize as DataTable;
                        dt.WriteXml(context.HttpContext.Response.OutputStream);
                        break;

                    default:
                        var xs = new XmlSerializer(_objectToSerialize.GetType());
                        xs.Serialize(context.HttpContext.Response.Output, _objectToSerialize);
                        break;
                }

            }
        }
        public enum ObjectType
        {
            DataSet,
            DataTable,
            Object
        }
    }
}

新建controller 并写以下action

 public XmlResult GetXmlEmployees()
        {
            DataSet ds = Gateways.Northwind.Select(Tables.Employees,Tables.Employees.EmployeeID,Tables.Employees.Address,
                Tables.Employees.BirthDate,Tables.Employees.City,Tables.Employees.Country,Tables.Employees.EmployeeID,
                Tables.Employees.FirstName,Tables.Employees.LastName,Tables.Employees.Notes,Tables.Employees.PhotoPath)
            .SetSelectRange(40, 0, Tables.Employees.EmployeeID)
            .ToDataSet();
            ds.DataSetName = "Employees";
            ds.Tables[0].TableName = "Employee";
            return new XmlResult(ds, XmlResult.ObjectType.DataSet);
        }

数据已准备OK

下面写mxml,代码如下:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" initialize="employeeService.send()" layout="absolute">
<mx:Script>
    <![CDATA[
        import mx.rpc.events.ResultEvent;
        import mx.collections.ArrayCollection;
        
        [Bindable]
        private var employeeData:ArrayCollection;
        private function resultHandler(event:ResultEvent):void{
            // Http Service resultFormat property
            // Possible formats 
            // object, xml, flashvars, text, e4x, array;
            employeeData = event.result.Employees.Employee;
        }
        // Flex list-based controls:
        // DataGrid, List, Tree, Menu, TileList and HorizontalList
    ]]>
</mx:Script>
    <mx:HTTPService id="employeeService" url="http://localhost:1819/Employee/GetXmlEmployees"
         result="resultHandler(event)" requestTimeout="60">
        
    </mx:HTTPService>
    <mx:DataGrid dataProvider="{employeeData}" width="100%" height="100%" />
</mx:Application>

Demo完成!!