SqlDataSourceCommandEventHandler Delegato

Definizione

Rappresenta il metodo che gestirà gli eventi Updating, Inserting e Deleting del controllo SqlDataSource.Represents the method that will handle the Updating, Inserting, and Deleting events of the SqlDataSource control.

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

Parametri

sender
Object

Origine dell'evento, ovvero il controllo SqlDataSource.The source of the event, the SqlDataSource control.

e
SqlDataSourceCommandEventArgs

Oggetto SqlDataSourceCommandEventArgs che contiene i dati dell'evento.A SqlDataSourceCommandEventArgs that contains the event data.

Ereditarietà
SqlDataSourceCommandEventHandler

Esempio

Nell'esempio di codice seguente viene illustrato come gestire Inserting l'evento per eseguire tutti i passaggi di pre-elaborazione, ad esempio l'aggiunta DbCommand di un parametro all' SqlDataSourceCommandEventArgs oggetto contenuto da per acquisire il valore di un parametro di output, prima di un viene eseguita l'azione di database.The following code example demonstrates how to handle the Inserting event to perform any preprocessing steps, such as adding a parameter to the DbCommand object contained by the SqlDataSourceCommandEventArgs to capture the value of an output parameter, before a database action is performed. In questo esempio un inserimento viene eseguito da un DetailsView controllo in uno scenario Master-Details classico, usando un stored procedure.In this example an insert is performed by a DetailsView control in a classic master-detail scenario, using a stored procedure. Il valore del parametro di output, che rappresenta la chiave primaria della riga appena inserita, viene esaminato quando l' Inserted evento viene generato al termine dell'operazione.The value of the output parameter, which represents the primary key of the newly inserted row, is examined when the Inserted event is raised after the operation completes.

<%@Page  Language="C#" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
 private void On_Inserting(Object sender, SqlDataSourceCommandEventArgs e) {

    SqlParameter insertedKey = new SqlParameter("@PK_New", SqlDbType.Int);
    insertedKey.Direction    = ParameterDirection.Output;        
    e.Command.Parameters.Add(insertedKey);
 }

 private void On_Inserted(Object sender, SqlDataSourceStatusEventArgs e) {
    DbCommand command = e.Command;    
    
    // The label displays the primary key of the recently inserted row.
    Label1.Text = command.Parameters["@PK_New"].Value.ToString();
    
    // Force a refresh after the data is inserted.
    GridView1.DataBind();
 }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:GridView
        id="GridView1"
        runat="server"
        AutoGenerateColumns="False"
        DataKeyNames="EmployeeID"        
        DataSourceID="SqlDataSource1">
        <columns>          
          <asp:BoundField HeaderText="First Name" DataField="FirstName" />
          <asp:BoundField HeaderText="Last Name" DataField="LastName" />
          <asp:BoundField HeaderText="Title" DataField="Title" />
          <asp:ButtonField ButtonType="Link" CommandName="Select" Text="Details..." />
        </columns>
      </asp:GridView>

      <asp:SqlDataSource
        id="SqlDataSource1"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind %>"
        SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees">
      </asp:SqlDataSource>

      <hr />

      <asp:DetailsView
        id="DetailsView1"
        runat="server"
        DataSourceID="SqlDataSource2"
        AutoGenerateRows="False"
        AutoGenerateInsertButton="True">
        <fields>
          <asp:BoundField HeaderText="First Name" DataField="FirstName" ReadOnly="False"/>
          <asp:BoundField HeaderText="Last Name" DataField="LastName" ReadOnly="False"/>
          <asp:TemplateField HeaderText="Title">
            <ItemTemplate>
              <asp:DropDownList
                id="TitleDropDownList"
                runat="server"
                selectedvalue="<%# Bind('Title') %>" >
                <asp:ListItem Selected="True">Sales Representative</asp:ListItem>
                <asp:ListItem>Sales Manager</asp:ListItem>
                <asp:ListItem>Vice President, Sales</asp:ListItem>
              </asp:DropDownList>
            </ItemTemplate>
          </asp:TemplateField>
          <asp:BoundField HeaderText="Notes" DataField="Notes" ReadOnly="False"/>
        </fields>
      </asp:DetailsView>


      <asp:SqlDataSource
        id="SqlDataSource2"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
        SelectCommand="SELECT * FROM Employees"
        InsertCommandType = "StoredProcedure"
        InsertCommand="sp_insertemployee"        
        OnInserting="On_Inserting"
        OnInserted ="On_Inserted"
        FilterExpression="EmployeeID={0}">
        <FilterParameters>
          <asp:ControlParameter Name="EmployeeID" ControlId="GridView1" PropertyName="SelectedValue" />
        </FilterParameters>
      </asp:SqlDataSource>

<!-- 
     -- An example sp_insertemployee stored procedure that returns
     -- the primary key of the row that was inserted in an OUT parameter.
     CREATE PROCEDURE sp_insertemployee 
        @FirstName nvarchar(10), 
        @LastName nvarchar(20) , 
        @Title nvarchar(30), 
        @Notes nvarchar(200), 
        @PK_New int OUTPUT
      AS
        INSERT INTO Employees(FirstName,LastName,Title,Notes)VALUES (@FirstName,@LastName,@Title,@Notes)
        SELECT @PK_New = @@IDENTITY
        RETURN (1)    
      GO
-->      

      <asp:Label 
        id="Label1"
        runat="server" />
      
    </form>
  </body>
</html>
<%@Page  Language="VB" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

 Sub On_Inserting(ByVal sender As Object, ByVal e As SqlDataSourceCommandEventArgs)

    Dim insertedKey As SqlParameter  
    insertedKey = New SqlParameter("@PK_New", SqlDbType.Int)
    insertedKey.Direction    = ParameterDirection.Output     
    
    e.Command.Parameters.Add(insertedKey)

 End Sub 'On_Inserting

 Sub On_Inserted(ByVal sender As Object, ByVal e As SqlDataSourceStatusEventArgs)
    Dim command As DbCommand 
    command = e.Command
    
    ' The label displays the primary key of the recently inserted row.
    Label1.Text = command.Parameters("@PK_New").Value.ToString()    
    
    ' Explicitly call DataBind to refresh the data
    ' and show the newly inserted row.
    GridView1.DataBind()
 End Sub 'On_Inserted

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:GridView
        id="GridView1"
        runat="server"
        AutoGenerateColumns="False"
        DataKeyNames="EmployeeID"        
        DataSourceID="SqlDataSource1">
        <columns>          
          <asp:BoundField HeaderText="First Name" DataField="FirstName" />
          <asp:BoundField HeaderText="Last Name" DataField="LastName" />
          <asp:BoundField HeaderText="Title" DataField="Title" />
          <asp:ButtonField ButtonType="Link" CommandName="Select" Text="Details..." />
        </columns>
      </asp:GridView>

      <asp:SqlDataSource
        id="SqlDataSource1"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind %>"
        SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees">
      </asp:SqlDataSource>

      <hr />

      <asp:DetailsView
        id="DetailsView1"
        runat="server"
        DataSourceID="SqlDataSource2"
        AutoGenerateRows="False"
        AutoGenerateInsertButton="True">
        <fields>
          <asp:BoundField HeaderText="First Name" DataField="FirstName" ReadOnly="False"/>
          <asp:BoundField HeaderText="Last Name" DataField="LastName" ReadOnly="False"/>
          <asp:TemplateField HeaderText="Title">
            <ItemTemplate>
              <asp:DropDownList
                id="TitleDropDownList"
                runat="server"
                selectedvalue="<%# Bind('Title') %>" >
                <asp:ListItem Selected="True">Sales Representative</asp:ListItem>
                <asp:ListItem>Sales Manager</asp:ListItem>
                <asp:ListItem>Vice President, Sales</asp:ListItem>
              </asp:DropDownList>
            </ItemTemplate>
          </asp:TemplateField>
          <asp:BoundField HeaderText="Notes" DataField="Notes" ReadOnly="False"/>
        </fields>
      </asp:DetailsView>


      <asp:SqlDataSource
        id="SqlDataSource2"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
        SelectCommand="SELECT * FROM Employees"
        InsertCommandType = "StoredProcedure"
        InsertCommand="sp_insertemployee"        
        OnInserting="On_Inserting"
        OnInserted ="On_Inserted"
        FilterExpression="EmployeeID={0}">
        <FilterParameters>
          <asp:ControlParameter Name="EmployeeID" ControlId="GridView1" PropertyName="SelectedValue" />
        </FilterParameters>
      </asp:SqlDataSource>

<!-- 
     -- An example sp_insertemployee stored procedure that returns
     -- the primary key of the row that was inserted in an OUT parameter.
     CREATE PROCEDURE sp_insertemployee 
        @FirstName nvarchar(10), 
        @LastName nvarchar(20) , 
        @Title nvarchar(30), 
        @Notes nvarchar(200), 
        @PK_New int OUTPUT
      AS
        INSERT INTO Employees(FirstName,LastName,Title,Notes)VALUES (@FirstName,@LastName,@Title,@Notes)
        SELECT @PK_New = @@IDENTITY
        RETURN (1)    
      GO
-->      

      <asp:Label 
        id="Label1"
        runat="server" />
      
    </form>
  </body>
</html>

Nell'esempio di codice seguente viene illustrato come gestire RowUpdating l'evento generato GridView dal controllo, per eventualmente annullare un'azione del database eseguita da SqlDataSource GridView un controllo associato al controllo.The following code example demonstrates how to handle the RowUpdating event raised by the GridView control, to possibly cancel a database action performed by a SqlDataSource control associated with the GridView control.

<%@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">

 // Set helper text and cancel the update if the values submitted to update the row
 // do not meet requirements.
 private void OnRowUpdatingHandler(Object source, GridViewUpdateEventArgs e) {
    // You can examine the values submitted by the user and perform additional
    // processing as required.
    if (e.OldValues[0].Equals("Nancy")) {
        e.Cancel = true;
        Label1.Text="This Row is Not Updatable!";
    }
 }

 // Ensure any helper text is cleared.
 private void OnRowCancellingHandler(Object source, GridViewCancelEditEventArgs e) {
    Label1.Text="";
 }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          DataSourceMode="DataSet"
          ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
          SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees"
          UpdateCommand="Update Employees SET FirstName=@FirstName,LastName=@LastName,Title=@Title WHERE EmployeeID=@EmployeeID">
      </asp:SqlDataSource>

      <asp:GridView
          id="GridView1"
          runat="server"
          AutoGenerateColumns="False"
          DataKeyNames="EmployeeID"
          AutoGenerateEditButton="True"
          DataSourceID="SqlDataSource1"
          OnRowUpdating="OnRowUpdatingHandler"
          OnRowCancelingEdit="OnRowCancellingHandler">
          <columns>
              <asp:BoundField HeaderText="First Name" DataField="FirstName" />
              <asp:BoundField HeaderText="Last Name" DataField="LastName" />
              <asp:BoundField HeaderText="Title" DataField="Title" />
          </columns>
      </asp:GridView>

      <asp:Label
          id="Label1"
          runat="server">
      </asp:Label>

    </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">

 ' Set helper text and cancel the update if the values submitted to update the row
 ' do not meet requirements.
 Sub OnRowUpdatingHandler(ByVal source As Object, ByVal e As GridViewUpdateEventArgs)
    If e.OldValues(0).Equals("Nancy") Then
        e.Cancel = "True"
        Label1.Text="This Row is Not Updatable!"
    End If
 End Sub 'OnRowUpdatingHandler

 ' Ensure any helper text is cleared.
 Sub OnRowCancellingHandler(ByVal source As Object, ByVal e As GridViewCancelEditEventArgs)
    Label1.Text=""
 End Sub 'OnRowCancellingHandler
</script>


<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          DataSourceMode="DataSet"
          ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
          SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees"
          UpdateCommand="Update Employees SET FirstName=@FirstName,LastName=@LastName,Title=@Title WHERE EmployeeID=@EmployeeID">
      </asp:SqlDataSource>

      <asp:GridView
          id="GridView1"
          runat="server"
          AutoGenerateColumns="False"
          DataKeyNames="EmployeeID"
          AutoGenerateEditButton="True"
          DataSourceID="SqlDataSource1"
          OnRowUpdating="OnRowUpdatingHandler"
          OnRowCancelingEdit="OnRowCancellingHandler">
          <columns>
              <asp:BoundField HeaderText="First Name" DataField="FirstName" />
              <asp:BoundField HeaderText="Last Name" DataField="LastName" />
              <asp:BoundField HeaderText="Title" DataField="Title" />
          </columns>
      </asp:GridView>

      <asp:Label
          id="Label1"
          runat="server">
      </asp:Label>

    </form>
  </body>
</html>

Commenti

Quando si crea un delegato SqlDataSourceCommandEventHandler, si identifica il metodo che gestirà l'evento.When you create a SqlDataSourceCommandEventHandler delegate, you identify the method that will handle the event. Per associare l'evento al gestore eventi in uso, aggiungere all'evento un'istanza del delegato.To associate the event with your event handler, add an instance of the delegate to the event. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non venga rimosso il delegato.The event handler is called whenever the event occurs, unless you remove the delegate. Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.For more information about how to handle events, see Handling and Raising Events.

Metodi di estensione

GetMethodInfo(Delegate)

Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato.Gets an object that represents the method represented by the specified delegate.

Si applica a

Vedi anche