[ASP.NET] – Quelques astuces

[ASP.NET] – Quelques astuces

1 Conserver la position dans la page une fois celle-ci rechargée  

Il suffit d’ajouter l’attribut  MaintainScrollPositionOnPostback="true" dans la directive de la page

<%@ Page Language="C#" MasterPageFile="~/maquette.master" Trace="true" AutoEventWireup="true" CodeFile="MaintainScrollPositionOnPostbackDemo.aspx.cs" Inherits="MaintainScrollPositionOnPostbackDemo" Title="Untitled Page" MaintainScrollPositionOnPostback="true" %>

<asp:Content ID="Content1" ContentPlaceHolderID="cphContenu" Runat="Server">

</asp:Content>

2 Tracer une page ou le site entier

A -Trace : de la page

Il suffit d’ajouter l’attribut Trace (réglé à true) dans la directive de la page désirée

<%@ Page Language="C#" MasterPageFile="~/maquette.master" Trace="true" AutoEventWireup="true" CodeFile="MaintainScrollPositionOnPostbackDemo.aspx.cs" Inherits="MaintainScrollPositionOnPostbackDemo" Title="Untitled Page" MaintainScrollPositionOnPostback="true" %>

<asp:Content ID="Content1" ContentPlaceHolderID="cphContenu" Runat="Server">

</asp:Content>

B -Du site

Dans le fichier de configuration principal  web.config du site(à la racine du site

<system.web>

 <trace enabled="true" traceMode="SortByCategory" localOnly="true"/>

(d’autres attributs sont disponibles tells requestLimit )

Il suffit ensuite d’aller à la page trace.axd du site (ce qui donne une url du type http://www.monsite.com/trace.axd ) pour avoir les informations 

Note : on peut bien entendu ajouter ses propres traces(exemple : Trace.Write("ma trace");)

3 Custom DataBound control

Créer un control web personnalisé qui tire parti des datasources (AccessDataSource,SqlDataSource ,etc.) de ASP.NET 2.0

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Text;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Collections;

namespace ControlLibrary

{

    [ToolboxData("<{0}:SimpleDataBoundColumn runat=server></{0}:SimpleDataBoundColumn>")]

    public class SimpleDataBoundColumn : DataBoundControl

    {

        public string DataTextField

        {

            get

            {

                object o = ViewState["DataTextField"];

                return ((o == null) ? string.Empty : (string)o);

            }

            set

            {

                ViewState["DataTextField"] = value;

                if (Initialized)

                {

                    OnDataPropertyChanged();

                }

            }

        }

        protected override void PerformSelect()

        {

            // si DataSourceID du control n'est pas définie

            if (!IsBoundUsingDataSourceID)

                this.OnDataBinding(EventArgs.Empty);

            GetData().Select(CreateDataSourceSelectArguments(),this.OnDataSourceViewSelectCallback);

            RequiresDataBinding = false;

            MarkAsDataBound();

            // declenchement evenement databound

            OnDataBound(EventArgs.Empty);

        }

        private void OnDataSourceViewSelectCallback(IEnumerable retrievedData)

        {

            // DataSourceID du control est définie

            if (IsBoundUsingDataSourceID)

                OnDataBinding(EventArgs.Empty);

            PerformDataBinding(retrievedData);

        }

        protected override void PerformDataBinding(IEnumerable retrievedData)

        {

            base.PerformDataBinding(retrievedData);

            int index = 0;

            if (retrievedData != null)

            {

                Table table = new Table();

                table.BorderWidth = 1;

                foreach (object dataItem in retrievedData)

                {

                    TableRow row = new TableRow();

                    if (DataTextField.Length > 0)

                    {

                        TableCell cell = new TableCell();

                        cell.Text = DataBinder.GetPropertyValue(dataItem, DataTextField, null);

                        row.Cells.Add(cell);

                    }

                    else

                    {

                        PropertyDescriptorCollection propertyDescriptors = TypeDescriptor.GetProperties(dataItem);

                        // création du header

                        if (index == 0)

                        {

                            TableRow headerRow = new TableRow();

                            headerRow.BackColor = System.Drawing.Color.LightGray;

                            foreach (PropertyDescriptor propertyDescriptor in propertyDescriptors)

                            {

                                TableCell cell = new TableCell();

                                cell.Text = propertyDescriptor.Name;

                                headerRow.Cells.Add(cell);

                            }

                            table.Rows.Add(headerRow);

                            index += 1;

                        }

                        // création des lignes de données

                        if (propertyDescriptors.Count >= 1)

                        {

                            foreach (PropertyDescriptor propertyDescriptor in propertyDescriptors)

                            {

                                if (propertyDescriptor.GetValue(dataItem) != null)

                                {

                                    TableCell cell = new TableCell();

                                    cell.Text = propertyDescriptor.GetValue(dataItem).ToString();

                                    row.Cells.Add(cell);

                                }

                            }

                        }

                    }

                    table.Rows.Add(row);

                }

                this.Controls.Add(table);

            }

        }

    }

}

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register Assembly="ControlLibrary" Namespace="ControlLibrary" TagPrefix="cc1" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">

    <title>Page sans titre</title>

</head>

<body>

    <form id="form1" runat="server">

    <div>

        <cc1:SimpleDataBoundColumn ID="SimpleDataBoundColumn1" runat="server" DataSourceID="SqlDataSource1"

            DataTextField="" />

        &nbsp;

        <br />

        <br />

        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ContactDBConnectionString %>"

            SelectCommand="SELECT [ContactID], [ContactName], [ContactFirstName], [ContactAge], [ContactCategoryID] FROM [Contact]">

        </asp:SqlDataSource>

        &nbsp;<br />

        <br />

    </div>

    </form>

http://msdn2.microsoft.com/fr-fr/library/ms366539(VS.80).aspx