Web parts 通信

1. 定义通信接口

public   interface  IEmployeeInfo
{
     int  EmployeeID {  get ;  set ; }
}

2. 在提供者中定义接口成员

 

     public   class  EmployeesWebPart : WebPart, IEmployeeInfo
    {
        [Personalizable( true ), WebBrowsable( true )]
         public   int  EmployeeID
        {
             get  {  return  _empID; }
             set  { _empID  =  value; }
        }
     //
    }

3. 在提供者中实现[ConnectionProvider]方法

 

     public   class  EmployeesWebPart : WebPart, IEmployeeInfo
     {
        [Personalizable(true), WebBrowsable(true)]
        public int EmployeeID
        {
            get { return _empID; }
            set { _empID = value; }
        }
        //

        // 定义ProvideEmployeeInfo方法，传送连接数据
        [ConnectionProvider("EmployeeIDProvider", "EmployeeIDProvider")]
        public IEmployeeInfo ProvideEmployeeInfo()
        {
            return this;
        }

        //
    }

4. 在订阅者中实现[ConnectionConsumer]方法

     public   class  OrdersWebPart : WebPart
     {
        public OrdersWebPart()
        {
            this.Title = "通信订阅者";
        }

        private int _empID;
        private GridView gv = new GridView();
        private AccessDataSource ads;

        protected override void RenderContents(HtmlTextWriter writer)
        {
            if (_empID < 1)
            {
                writer.Write("<span style='color:gray'>请在文本框中输入大于等于1的值.</span>");
                return;
            }
            else
            {
                ads = new AccessDataSource();
                Controls.Add(ads);
                ads.ID = "accessDatasource1";
                ads.DataFile = "~/App_Data/NorthWind.mdb";
                ads.SelectCommand = "SELECT top 8 orderid, customerid,employeeid, orderdate from orders where employeeid=" + _empID.ToString();

                gv = new GridView();
                Controls.Add(gv);
                gv.DataSourceID = "accessDatasource1";
                gv.CellPadding = 3;
                gv.GridLines = GridLines.None;
                gv.RenderControl(writer);
            }
        }

        [ConnectionConsumer("EmployeeIDConsumer", "EmployeeIDConsumer")]
        public void GetEmployeeInfo(IEmployeeInfo empInfo)
        {
            if (empInfo != null)
                _empID = empInfo.EmployeeID;
            else
                throw new NotSupportedException("未能连接数据库");
        }
    }

 

5. 在WebPartManager控件中声明连接.

< table  border ="0" >
                     < tr >
                         < td  colspan ="2" >
                             < asp:WebPartManager  ID ="WebPartManager1"  runat ="server" >
                                 < StaticConnections >
                                     < asp:WebPartConnection  ID ="EmpConnection"  ProviderID ="EmployeesWebPart1"  ProviderConnectionPointID ="EmployeeIDProvider"
                                        ConsumerID ="OrdersWebPart1"  ConsumerConnectionPointID ="EmployeeIDConsumer"   />
                                 </ StaticConnections >
                             </ asp:WebPartManager >
                         </ td >
                     </ tr >
                     < tr  valign ="top" >
                         < td >
                             < asp:WebPartZone  ID ="WebPartZone1"  runat ="server"  Width ="300px" >
                             < ZoneTemplate >
                                 < cw1:EmployeesWebPart  ID ="EmployeesWebPart1"  runat ="server"  EmployeeID ="1"   />
                             </ ZoneTemplate >
                             </ asp:WebPartZone >   </ td >
                         < td >
                             < asp:WebPartZone  ID ="WebPartZone2"  runat ="server"  Width ="300px" >
                                 < ZoneTemplate >
                                     < cw1:OrdersWebPart  ID ="OrdersWebPart1"  runat ="server"   />
                                 </ ZoneTemplate >
                             </ asp:WebPartZone >
                             </ td >
                     </ tr >
                 </ table >