SqlDataSourceCommandEventHandler Delegato

Definizione

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

Assembly:: System.Web.dll

Importante

Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.

Rappresenta il metodo che gestirà gli Updatingeventi , Insertinge Deleting del SqlDataSource controllo .

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, il SqlDataSource controllo .

e: SqlDataSourceCommandEventArgs

Oggetto SqlDataSourceCommandEventArgs contenente i dati dell'evento.

Esempio

Nell'esempio di codice seguente viene illustrato come gestire l'evento Inserting per eseguire qualsiasi procedura di pre-elaborazione, ad esempio l'aggiunta di un parametro all'oggetto DbCommand contenuto da SqlDataSourceCommandEventArgs per acquisire il valore di un parametro di output, prima dell'esecuzione di un'azione del database. In questo esempio un inserimento viene eseguito da un DetailsView controllo in uno scenario master-dettagli classico, usando una stored procedure. Il valore del parametro di output, che rappresenta la chiave primaria della riga appena inserita, viene esaminato quando l'evento Inserted viene generato al termine dell'operazione.

<%@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 l'evento RowUpdating generato dal GridView controllo , per annullare eventualmente un'azione di database eseguita da un SqlDataSource controllo associato al GridView 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">

 // 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 SqlDataSourceCommandEventHandler delegato, si identifica il metodo che gestirà l'evento. Per associare l'evento al gestore eventi, aggiungere un'istanza del delegato all'evento. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non si rimuovono il delegato. Per altre informazioni su come gestire gli eventi, vedere Gestione e generazione di eventi.

Metodi di estensione

Nome	Descrizione
GetMethodInfo(Delegate)	Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato.

Si applica a

Vedi anche

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