DataList.OnItemCreated(DataListItemEventArgs) Método

  • Referência

Definição

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Aciona o evento ItemCreated. Isso permite que você forneça um manipulador personalizado para o evento.

protected:
 virtual void OnItemCreated(System::Web::UI::WebControls::DataListItemEventArgs ^ e);
protected virtual void OnItemCreated (System.Web.UI.WebControls.DataListItemEventArgs e);
abstract member OnItemCreated : System.Web.UI.WebControls.DataListItemEventArgs -> unit
override this.OnItemCreated : System.Web.UI.WebControls.DataListItemEventArgs -> unit
Protected Overridable Sub OnItemCreated (e As DataListItemEventArgs)

Parâmetros

e
DataListItemEventArgs

Um DataListItemEventArgs que contém dados do evento.

Exemplos

O exemplo de código a seguir demonstra como especificar e codificar um manipulador para o ItemCreated evento para exibir a ordem na qual os DataList itens no controle são criados.

Observação

O exemplo de código a seguir usa o modelo de código de arquivo único e pode não funcionar corretamente se copiado diretamente em um arquivo code-behind. Este exemplo de código deve ser copiado em um arquivo de texto vazio que tenha uma extensão .aspx. Para obter mais informações sobre o modelo de código do Web Forms, consulte ASP.NET Modelo de Código de Página dos Web Forms.


<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!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" >
   <script runat="server">
 
      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataList control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(String)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         // Populate the table with sample values.
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Description for item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;

      }
 
 
      void Page_Load(Object sender, EventArgs e) 
      {

         // Load sample data only once, when the page is first loaded.
         if (!IsPostBack) 
         {
            ItemsList.DataSource = CreateDataSource();
            ItemsList.DataBind();
         }

      }

      void Item_Created(Object sender, DataListItemEventArgs e)
      {

         if (e.Item.ItemType == ListItemType.Item || 
             e.Item.ItemType == ListItemType.AlternatingItem)
         {

            // Retrieve the Label control in the current DataListItem.
            Label PriceLabel = (Label)e.Item.FindControl("PriceLabel");

            // Retrieve the text of the CurrencyColumn from the DataListItem
            // and convert the value to a Double.
            Double Price = Convert.ToDouble(
                ((DataRowView)e.Item.DataItem).Row.ItemArray[2].ToString());

            // Format the value as currency and redisplay it in the DataList.
            PriceLabel.Text = Price.ToString("c");

         }

      }
 
   </script>
 
<head runat="server">
    <title>DataList ItemCreated Example</title>
</head>
<body>
 
   <form id="form1" runat="server">

      <h3>DataList ItemCreated Example</h3>
 
      <asp:DataList id="ItemsList"
           BorderColor="black"
           CellPadding="5"
           CellSpacing="5"
           RepeatDirection="Vertical"
           RepeatLayout="Table"
           RepeatColumns="3"
           OnItemCreated="Item_Created"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <HeaderTemplate>

            List of items

         </HeaderTemplate>
               
         <ItemTemplate>

            Description: <br />
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>

            <br />

            Price: 
            <asp:Label id="PriceLabel"
                 runat="server"/>

         </ItemTemplate>
 
      </asp:DataList>
 
   </form>
 
</body>
</html>


<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!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" >
   <script runat="server">
 
      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataList control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))
 
         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 To 8 

            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Description for item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)

         Next i
 
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
 
      Sub Page_Load(sender As Object, e As EventArgs) 

         ' Load sample data only once, when the page is first loaded.
         If Not IsPostBack Then
         
            ItemsList.DataSource = CreateDataSource()
            ItemsList.DataBind()
         
         End If

      End Sub

      Sub Item_Created(sender As Object, e As DataListItemEventArgs)

         If e.Item.ItemType = ListItemType.Item Or _
             e.Item.ItemType = ListItemType.AlternatingItem Then


            ' Retrieve the Label control in the current DataListItem.
            Dim PriceLabel As Label = _
                CType(e.Item.FindControl("PriceLabel"), Label)

            ' Retrieve the text of the CurrencyColumn from the DataListItem
            ' and convert the value to a Double.
            Dim Price As Double = Convert.ToDouble( _
                (CType(e.Item.DataItem, DataRowView)).Row.ItemArray(2).ToString())

            ' Format the value as currency and redisplay it in the DataList.
            PriceLabel.Text = Price.ToString("c")

         End If

      End Sub
 
   </script>
 
<head runat="server">
    <title>DataList ItemCreated Example</title>
</head>
<body>
 
   <form id="form1" runat="server">

      <h3>DataList ItemCreated Example</h3>
 
      <asp:DataList id="ItemsList"
           BorderColor="black"
           CellPadding="5"
           CellSpacing="5"
           RepeatDirection="Vertical"
           RepeatLayout="Table"
           RepeatColumns="3"
           OnItemCreated="Item_Created"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <HeaderTemplate>

            List of items

         </HeaderTemplate>
               
         <ItemTemplate>

            Description: <br />
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>

            <br />

            Price: 
            <asp:Label id="PriceLabel"
                 runat="server"/>

         </ItemTemplate>
 
      </asp:DataList>
 
   </form>
 
</body>
</html>


<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!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" >
   <script runat="server">
 
      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataList control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(String)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         // Populate the table with sample values.
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Description for item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;

      }
 
 
      void Page_Load(Object sender, EventArgs e) 
      {

         // Manually register the event-handling method for the 
         // ItemCommand event.
         ItemsList.ItemCreated += 
             new DataListItemEventHandler(this.Item_Created);

         // Load sample data only once, when the page is first loaded.
         if (!IsPostBack) 
         {
            ItemsList.DataSource = CreateDataSource();
            ItemsList.DataBind();
         }

      }

      void Item_Created(Object sender, DataListItemEventArgs e)
      {

         if (e.Item.ItemType == ListItemType.Item || 
             e.Item.ItemType == ListItemType.AlternatingItem)
         {

            // Retrieve the Label control in the current DataListItem.
            Label PriceLabel = (Label)e.Item.FindControl("PriceLabel");

            // Retrieve the text of the CurrencyColumn from the DataListItem
            // and convert the value to a Double.
            Double Price = Convert.ToDouble(
                ((DataRowView)e.Item.DataItem).Row.ItemArray[2].ToString());

            // Format the value as currency and redisplay it in the DataList.
            PriceLabel.Text = Price.ToString("c");

         }

      }
 
   </script>
 
<head runat="server">
    <title>DataList ItemCreated Example</title>
</head>
<body>
 
   <form id="form1" runat="server">

      <h3>DataList ItemCreated Example</h3>
 
      <asp:DataList id="ItemsList"
           BorderColor="black"
           CellPadding="5"
           CellSpacing="5"
           RepeatDirection="Vertical"
           RepeatLayout="Table"
           RepeatColumns="3"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <HeaderTemplate>

            List of items

         </HeaderTemplate>
               
         <ItemTemplate>

            Description: <br />
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>

            <br />

            Price: 
            <asp:Label id="PriceLabel"
                 runat="server"/>

         </ItemTemplate>
 
      </asp:DataList>
 
   </form>
 
</body>
</html>


<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!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" >
   <script runat="server">
 
      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataList control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))
 
         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 To 8 

            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Description for item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)

         Next i
 
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
 
      Sub Page_Load(sender As Object, e As EventArgs) 

         ' Manually register the event-handling method for the 
         ' ItemCommand event.
         AddHandler ItemsList.ItemCreated, AddressOf Item_Created

         ' Load sample data only once, when the page is first loaded.
         If Not IsPostBack Then
         
            ItemsList.DataSource = CreateDataSource()
            ItemsList.DataBind()
         
         End If

      End Sub

      Sub Item_Created(sender As Object, e As DataListItemEventArgs)

         If e.Item.ItemType = ListItemType.Item Or _
             e.Item.ItemType = ListItemType.AlternatingItem Then


            ' Retrieve the Label control in the current DataListItem.
            Dim PriceLabel As Label = CType( _
                e.Item.FindControl("PriceLabel"), Label)

            ' Retrieve the text of the CurrencyColumn from the DataListItem
            ' and convert the value to a Double.
            Dim Price As Double = Convert.ToDouble( _
                (CType(e.Item.DataItem, DataRowView)).Row.ItemArray(2).ToString())

            ' Format the value as currency and redisplay it in the DataList.
            PriceLabel.Text = Price.ToString("c")

         End If

      End Sub
 
   </script>
 
<head runat="server">
    <title>DataList ItemCreated Example</title>
</head>
<body>
 
   <form id="form1" runat="server">

      <h3>DataList ItemCreated Example</h3>
 
      <asp:DataList id="ItemsList"
           BorderColor="black"
           CellPadding="5"
           CellSpacing="5"
           RepeatDirection="Vertical"
           RepeatLayout="Table"
           RepeatColumns="3"
           OnItemCreated="Item_Created"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <HeaderTemplate>

            List of items

         </HeaderTemplate>
               
         <ItemTemplate>

            Description: <br />
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>

            <br />

            Price: 
            <asp:Label id="PriceLabel"
                 runat="server"/>

         </ItemTemplate>
 
      </asp:DataList>
 
   </form>
 
</body>
</html>

Comentários

Use o OnItemCreated método para fornecer um manipulador personalizado para o ItemCreated evento.

O ItemCreated evento é gerado quando um item no DataList controle é criado, tanto durante viagens de ida e volta quanto no momento em que os dados são associados ao controle.

O ItemCreated evento é comumente usado para controlar o conteúdo e a aparência de uma linha no DataList controle.

A geração de um evento invoca o manipulador de eventos por meio de um delegado. Para obter mais informações, consulte Como consumir eventos em um aplicativo web forms.

O OnItemCreated método também permite que classes derivadas manipulem o evento sem anexar um delegado. Essa é a técnica preferencial para lidar com o evento em uma classe derivada.

Notas aos Herdeiros

Ao substituir OnItemCreated(DataListItemEventArgs) em uma classe derivada, chame o método da OnItemCreated(DataListItemEventArgs) classe base para que os delegados registrados recebam o evento.

Aplica-se a

Confira também