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>