DetailsViewInsertEventHandler Delegato

  • Riferimento

Definizione

Spazio dei nomi:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Rappresenta il metodo che gestisce l'evento ItemInserting di un controllo DetailsView.

public delegate void DetailsViewInsertEventHandler(System::Object ^ sender, DetailsViewInsertEventArgs ^ e);
public delegate void DetailsViewInsertEventHandler(object sender, DetailsViewInsertEventArgs e);
type DetailsViewInsertEventHandler = delegate of obj * DetailsViewInsertEventArgs -> unit
Public Delegate Sub DetailsViewInsertEventHandler(sender As Object, e As DetailsViewInsertEventArgs)

Parametri

sender
Object

Origine dell'evento.

e
DetailsViewInsertEventArgs

Oggetto DetailsViewInsertEventArgs che contiene i dati dell'evento.

Esempio

Nell'esempio di codice seguente viene illustrato come aggiungere un DetailsViewInsertEventHandler delegato a livello di codice all'evento ItemInserting di un DetailsView controllo .


<%@ Page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
  
  void Page_Load(Object sender, EventArgs e)
  {

    // Create a new DetailsView object.
    DetailsView customerDetailsView = new DetailsView();

    // Set the DetailsView object's properties.
    customerDetailsView.ID = "CustomerDetailsView";
    customerDetailsView.DataSourceID = "DetailsViewSource";
    customerDetailsView.AutoGenerateRows = true;
    customerDetailsView.AutoGenerateInsertButton = true;
    customerDetailsView.AllowPaging = true;
    customerDetailsView.DataKeyNames = new String[1] { "CustomerID" };
    
    // Programmatically register the event-handling method
    // for the ItemInserted event of a DetailsView control.
    customerDetailsView.ItemInserting += new DetailsViewInsertEventHandler(this.CustomerDetailsView_ItemInserting);

    // Add the DetailsView object to the Controls collection
    // of the PlaceHolder control.
    DetailsViewPlaceHolder.Controls.Add(customerDetailsView);

  }

  void CustomerDetailsView_ItemInserting(Object sender, DetailsViewInsertEventArgs e)
  {
    // Use the Values property to retrieve the key field value.
    String keyValue = e.Values["CustomerID"].ToString();

    // Insert the record only if the key field is four characters
    // long; otherwise, cancel the insert operation.
    if (keyValue.Length == 4)
    {
      // Change the key field value to upper case before inserting 
      // the record in the data source.
      e.Values["CustomerID"] = keyValue.ToUpper();

      MessageLabel.Text = "";
    }
    else
    {
      MessageLabel.Text = "The key field must have four digits.";
      e.Cancel = true;
    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewInsertEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewInsertEventHandler Example</h3>
        
      <!-- Use a PlaceHolder control as the container for the -->
      <!-- dynamically generated DetailsView control.         -->       
      <asp:PlaceHolder id="DetailsViewPlaceHolder"
        runat="server"/>
        
      <br/><br/>
      
      <asp:label id="MessageLabel"
        forecolor="Red"
        runat="server"/>
          
      <!-- This example uses Microsoft SQL Server and connects  -->
      <!-- to the Northwind sample database. Use an ASP.NET     -->
      <!-- expression to retrieve the connection string value   -->
      <!-- from the web.config file.                            -->
      <asp:sqldatasource id="DetailsViewSource"
        selectcommand="Select [CustomerID], [CompanyName], [Address], 
          [City], [PostalCode], [Country] From [Customers]"
        insertcommand="INSERT INTO [Customers]([CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country]) VALUES (@CustomerID, @CompanyName, @Address, @City, @PostalCode, @Country)"
        connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
            
    </form>
  </body>
</html>


<%@ Page language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
  
  Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

    ' Create a new DetailsView object.
    Dim customerDetailsView As New DetailsView()

    ' Set the DetailsView object's properties.
    customerDetailsView.ID = "CustomerDetailsView"
    customerDetailsView.DataSourceID = "DetailsViewSource"
    customerDetailsView.AutoGenerateRows = True
    customerDetailsView.AutoGenerateInsertButton = True
    customerDetailsView.AllowPaging = True
    
    Dim keyArray() As String = {"CustomerID"}
    customerDetailsView.DataKeyNames = keyArray
    
    ' Programmatically register the event-handling method
    ' for the ItemInserted event of a DetailsView control.
    AddHandler customerDetailsView.ItemInserting, AddressOf CustomerDetailsView_ItemInserting

    ' Add the DetailsView object to the Controls collection
    ' of the PlaceHolder control.
    DetailsViewPlaceHolder.Controls.Add(customerDetailsView)

  End Sub

  Sub CustomerDetailsView_ItemInserting(ByVal sender As Object, ByVal e As DetailsViewInsertEventArgs)
    
    ' Use the Values property to retrieve the key field value.
    Dim keyValue As String = e.Values("CustomerID").ToString()

    ' Insert the record only if the key field is four characters
    ' long; otherwise, cancel the insert operation.
    If keyValue.Length = 4 Then
    
      ' Change the key field value to upper case before inserting 
      ' the record in the data source.
      e.Values("CustomerID") = keyValue.ToUpper()
      
      MessageLabel.Text = ""
    
    Else
    
      MessageLabel.Text = "The key field must have four digits."
      e.Cancel = True
    
    End If

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewInsertEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewInsertEventHandler Example</h3>
        
      <!-- Use a PlaceHolder control as the container for the -->
      <!-- dynamically generated DetailsView control.         -->       
      <asp:PlaceHolder id="DetailsViewPlaceHolder"
        runat="server"/>
        
      <br/><br/>
      
      <asp:label id="MessageLabel"
        forecolor="Red"
        runat="server"/>
          
      <!-- This example uses Microsoft SQL Server and connects  -->
      <!-- to the Northwind sample database. Use an ASP.NET     -->
      <!-- expression to retrieve the connection string value   -->
      <!-- from the web.config file.                            -->
      <asp:sqldatasource id="DetailsViewSource"
        selectcommand="Select [CustomerID], [CompanyName], [Address], 
          [City], [PostalCode], [Country] From [Customers]"
        insertcommand="INSERT INTO [Customers]([CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country]) VALUES (@CustomerID, @CompanyName, @Address, @City, @PostalCode, @Country)"
        connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
            
    </form>
  </body>
</html>

Nell'esempio di codice seguente viene illustrato come aggiungere in modo dichiarativo un DetailsViewInsertEventHandler delegato all'evento ItemInserting di un DetailsView controllo .


<%@ Page language="C#" %>

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

  void CustomerDetailsView_ItemInserting(Object sender, 
    DetailsViewInsertEventArgs e)
  {
    // Use the Values property to retrieve the key field value.
    String keyValue = e.Values["CustomerID"].ToString();

    // Insert the record only if the key field is four characters
    // long; otherwise, cancel the insert operation.
    if (keyValue.Length == 4)
    {
      // Change the key field value to upper case before inserting 
      // the record in the data source.
      e.Values["CustomerID"] = keyValue.ToUpper();

      MessageLabel.Text = "";
    }
    else
    {
      MessageLabel.Text = "The key field must have four digits.";
      e.Cancel = true;
    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewInsertEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewInsertEventHandler Example</h3>
                
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          datakeynames="CustomerID"
          autogenerateinsertbutton="true"  
          autogeneraterows="true"
          allowpaging="true"
          oniteminserting="CustomerDetailsView_ItemInserting" 
          runat="server">
               
          <fieldheaderstyle backcolor="Navy"
            forecolor="White"/>
                    
        </asp:detailsview>
        
        <asp:label id="MessageLabel"
          forecolor="Red"
          runat="server"/>
            
        <!-- This example uses Microsoft SQL Server and connects  -->
        <!-- to the Northwind sample database. Use an ASP.NET     -->
        <!-- expression to retrieve the connection string value   -->
        <!-- from the web.config file.                            -->
        <asp:sqldatasource id="DetailsViewSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          insertcommand="INSERT INTO [Customers]([CustomerID], 
            [CompanyName], [Address], [City], [PostalCode], 
            [Country]) VALUES (@CustomerID, @CompanyName, @Address, 
            @City, @PostalCode, @Country)"
          connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>


<%@ Page language="VB" autoeventwireup="false" %>

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

  Sub CustomerDetailsView_ItemInserting(ByVal sender As Object, _
    ByVal e As DetailsViewInsertEventArgs) _
    Handles CustomerDetailsView.ItemInserting
  
    ' Use the Values property to retrieve the key field value.
    Dim keyValue As String = e.Values("CustomerID").ToString()

    ' Insert the record only if the key field is four characters
    ' long; otherwise, cancel the insert operation.
    If keyValue.Length = 4 Then
    
      ' Change the key field value to upper case before inserting 
      ' the record in the data source.
      e.Values("CustomerID") = keyValue.ToUpper()
      
      MessageLabel.Text = ""
    
    Else
    
      MessageLabel.Text = "The key field must have four digits."
      e.Cancel = True
    
    End If

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewInsertEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewInsertEventHandler Example</h3>
                
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          datakeynames="CustomerID"
          autogenerateinsertbutton="true"  
          autogeneraterows="true"
          allowpaging="true"
          oniteminserting="CustomerDetailsView_ItemInserting" 
          runat="server">
               
          <fieldheaderstyle backcolor="Navy"
            forecolor="White"/>
                    
        </asp:detailsview>
        
        <asp:label id="MessageLabel"
          forecolor="Red"
          runat="server"/>
            
        <!-- This example uses Microsoft SQL Server and connects  -->
        <!-- to the Northwind sample database. Use an ASP.NET     -->
        <!-- expression to retrieve the connection string value   -->
        <!-- from the web.config file.                            -->
        <asp:sqldatasource id="DetailsViewSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          insertcommand="INSERT INTO [Customers]([CustomerID], 
            [CompanyName], [Address], [City], [PostalCode], 
            [Country]) VALUES (@CustomerID, @CompanyName, @Address, 
            @City, @PostalCode, @Country)"
          connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>

Commenti

Il DetailsView controllo genera l'evento ItemInserting quando viene fatto clic su un pulsante Inserisci (un pulsante con la relativa CommandName proprietà impostata su "Inserisci") all'interno del controllo, ma prima che il DetailsView controllo inserisca il record. In questo modo è possibile fornire un gestore eventi che esegue una routine personalizzata, ad esempio la codifica HTML dei valori di un record prima di inserirlo nell'origine dati, ogni volta che si verifica questo evento.

Quando si crea un delegato DetailsViewInsertEventHandler, si identifica il metodo che gestirà l'evento. Per associare l'evento al gestore eventi in uso, aggiungere all'evento un'istanza del delegato. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non venga rimosso il delegato. Per altre informazioni sui delegati del gestore eventi, vedere Gestione e generazione di eventi.

Metodi di estensione

GetMethodInfo(Delegate)

Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato.

Si applica a

Vedi anche