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GridViewDeleteEventArgs.Keys Proprietà

Definizione

Ottiene un dizionario delle coppie nome/valore dei campi che rappresentano la chiave primaria della riga da eliminare.

public:
 property System::Collections::Specialized::IOrderedDictionary ^ Keys { System::Collections::Specialized::IOrderedDictionary ^ get(); };
public System.Collections.Specialized.IOrderedDictionary Keys { get; }
member this.Keys : System.Collections.Specialized.IOrderedDictionary
Public ReadOnly Property Keys As IOrderedDictionary

Valore della proprietà

IOrderedDictionary

Un dizionario contenente coppie nome/valore dei campi che rappresentano la chiave primaria della riga da eliminare.

Esempio

Nell'esempio seguente viene illustrato come utilizzare la Values proprietà per ottenere i valori dei campi chiave per la riga da eliminare. I valori vengono quindi scritti in un file di log di record eliminati.


<%@ Page language="C#" %>
<%@ import namespace="System.IO" %>

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

  void CustomersGridView_RowDeleting(Object sender, GridViewDeleteEventArgs e)
  {

    // Record the delete operation in a log file.

    // Create the log text. 
    String logText = "";

    // Append the values of the key fields to the log text.
    foreach (DictionaryEntry keyEntry in e.Keys)
    {
      logText += keyEntry.Key + "=" + keyEntry.Value + ";";
    }

    // Append the values of the non-key fields to the log text.
    foreach (DictionaryEntry valueEntry in e.Values)
    {
      logText += valueEntry.Key + "=" + valueEntry.Value + ";";
    }

    // Display the log content.
    LogTextLabel.Text = logText;
    
    // Append the text to a log file.
    try
    {
      StreamWriter sw;
      sw = File.AppendText(Server.MapPath(null) + "\\deletelog.txt");
      sw.WriteLine(logText);
      sw.Flush();
      sw.Close();
    }
    catch(UnauthorizedAccessException ex)
    {
      // You must provide read/write access to the file using ACLs.
      LogErrorLabel.Text = "You do not have permission to write to the log.";
    }

  }
    
  void CustomersGridView_RowDeleted(Object sender, GridViewDeletedEventArgs e)
  {
    
    if (e.Exception == null)
    {
      // The delete operation succeeded. Clear the message label.
      Message.Text = "";
    }
    else
    {
      // The delete operation failed. Display an error message.
      Message.Text = e.AffectedRows.ToString() + " rows deleted. " + e.Exception.Message;
      e.ExceptionHandled = true;
    }
        
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewDeleteEventArgs Keys and Values Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewDeleteEventArgs Keys and Values Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"          
        runat="server"/>
        
      <br/>
      
      <asp:label id="LogTextLabel"
        forecolor="Red"          
        runat="server"/>
        
      <br/>
        
      <asp:label id="LogErrorLabel"
        forecolor="Red"          
        runat="server"/>
                
      <br/>

      <asp:gridview id="CustomersGridView" 
        allowpaging="true"
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogeneratedeletebutton="true" 
        datakeynames="CustomerID"
        onrowdeleted="CustomersGridView_RowDeleted"
        onrowdeleting="CustomersGridView_RowDeleting"   
        runat="server">
        
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        deletecommand="Delete from Customers where CustomerID = @CustomerID"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

<%@ Page language="VB" %>
<%@ import namespace="System.IO" %>

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

  Sub CustomersGridView_RowDeleting(ByVal sender As Object, ByVal e As GridViewDeleteEventArgs)

    ' Record the delete operation in a log file.

    ' Create the log text. 
    Dim logText As String = ""

    ' Append the values of the key fields to the log text.
    Dim i As Integer
    For i = 0 To e.Keys.Count - 1
    
      logText &= e.Keys(i).ToString() & ";"
      
    Next

    ' Append the values of the non-key fields to the log text.
    For i = 0 To e.Values.Count - 1
    
      If e.Values(i) IsNot Nothing Then
        logText &= e.Values(i).ToString() & ";"
      Else
        logText &= "Nothing" & ";"
      End If
      
    Next
    
    ' Display the log content.
    LogTextLabel.Text = logText

    ' Append the text to a log file.
    Try
    
      Dim sw As StreamWriter
      sw = File.AppendText(Server.MapPath(Nothing) & "\deletelog.txt")
      sw.WriteLine(logText)
      sw.Flush()
      sw.Close()
    
    Catch ex As UnauthorizedAccessException
    
      ' You must provide read/write access to the file using ACLs.
      LogErrorLabel.Text = "You do not have permission to write to the log."
    
    End Try

  End Sub
    
  Sub CustomersGridView_RowDeleted(ByVal sender As Object, ByVal e As GridViewDeletedEventArgs)
    
    If e.Exception Is Nothing Then
    
      ' The delete operation succeeded. Clear the message label.
      Message.Text = ""
    
    Else
    
      ' The delete operation failed. Display an error message.
      Message.Text = e.AffectedRows.ToString() & " rows deleted. " & e.Exception.Message
      e.ExceptionHandled = True
      
    End If
        
  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewDeleteEventArgs Keys and Values Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewDeleteEventArgs Keys and Values Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"          
        runat="server"/>
        
      <br/>
      
      <asp:label id="LogTextLabel"
        forecolor="Red"          
        runat="server"/>
        
      <br/>
        
      <asp:label id="LogErrorLabel"
        forecolor="Red"          
        runat="server"/>
                
      <br/>

      <asp:gridview id="CustomersGridView" 
        allowpaging="true"
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogeneratedeletebutton="true" 
        datakeynames="CustomerID"
        onrowdeleted="CustomersGridView_RowDeleted"
        onrowdeleting="CustomersGridView_RowDeleting"   
        runat="server">
        
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        deletecommand="Delete from Customers where CustomerID = @CustomerID"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

Commenti

Quando la DataKeyNames proprietà di un GridView controllo è impostata, utilizzare la Keys proprietà (dizionario) per ottenere il valore della chiave primaria o delle chiavi della riga da eliminare.

Nota

Per ottenere i valori dei campi non chiave, utilizzare la Values proprietà .

Il Keys dizionario viene popolato automaticamente con le coppie nome/valore del campo o dei campi specificati nella DataKeyNames proprietà . Se più campi formano la chiave primaria, viene aggiunta una voce separata al Keys dizionario per ogni campo chiave.

Per determinare il nome di un campo chiave, utilizzare la DictionaryEntry.Key proprietà di un System.Collections.DictionaryEntry oggetto nel Keys dizionario. Per determinare il valore di un campo chiave, utilizzare la DictionaryEntry.Value proprietà .

Si applica a

Vedi anche