GridViewUpdatedEventArgs.OldValues Właściwość

Odwołanie

Definicja

Przestrzeń nazw:: System.Web.UI.WebControls

Zestaw:: System.Web.dll

Ważne

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Pobiera słownik zawierający oryginalne pary nazwa/wartość pola dla zaktualizowanego rekordu.

public:
 property System::Collections::Specialized::IOrderedDictionary ^ OldValues { System::Collections::Specialized::IOrderedDictionary ^ get(); };

public System.Collections.Specialized.IOrderedDictionary OldValues { get; }

member this.OldValues : System.Collections.Specialized.IOrderedDictionary

Public ReadOnly Property OldValues As IOrderedDictionary

Wartość właściwości

IOrderedDictionary

Słownik oryginalnych par nazwa/wartość pola dla zaktualizowanego rekordu.

Przykłady

W poniższym przykładzie pokazano, jak uzyskać dostęp do oryginalnych wartości pól innych niż klucz dla zaktualizowanego rekordu.


<%@ 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 CustomersGridView_RowUpdated(Object sender, GridViewUpdatedEventArgs e)
  {
    // Use the Exception property to determine whether an exception
    // occurred during the update operation.
    if (e.Exception == null)
    {
      // Sometimes an error might occur that does not raise an 
      // exception, but prevents the update operation from 
      // completing. Use the AffectedRows property to determine 
      // whether the record was actually updated. 
      if (e.AffectedRows == 1)
      {
        // Use the Keys property to get the value of the key field.
        String keyFieldValue = e.Keys["CustomerID"].ToString();

        // Display a confirmation message.
        Message.Text = "Record " + keyFieldValue +
          " updated successfully. ";

        // Display the new and original values.
        DisplayValues((OrderedDictionary)e.NewValues, (OrderedDictionary)e.OldValues);
      }
      else
      {
        // Display an error message.
        Message.Text = "An error occurred during the update operation.";

        // When an error occurs, keep the GridView
        // control in edit mode.
        e.KeepInEditMode = true;
      }
    }
    else
    {
      // Insert the code to handle the exception.
      Message.Text = e.Exception.Message;

      // Use the ExceptionHandled property to indicate that the 
      // exception is already handled.
      e.ExceptionHandled = true;

      e.KeepInEditMode = true;
    }
  }

  void DisplayValues(OrderedDictionary newValues, OrderedDictionary oldValues)
  {

    Message.Text += "<br/></br>";

    // Iterate through the new and old values. Display the
    // values on the page.
    for (int i = 0; i < oldValues.Count; i++)
    {
      Message.Text += "Old Value=" + oldValues[i].ToString() +
        ", New Value=" + newValues[i].ToString() + "<br/>";
    }

    Message.Text += "</br>";

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewUpdatedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewUpdatedEventArgs Example</h3>
            
      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames property as read-only.    -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogenerateeditbutton="true"
        allowpaging="true" 
        datakeynames="CustomerID"
        onrowupdated="CustomersGridView_RowUpdated" 
        runat="server">
      </asp:gridview>
      
      <br/>
      
      <asp:label id="Message"
        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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </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 CustomersGridView_RowUpdated(sender As Object, e As GridViewUpdatedEventArgs)
  
    ' Use the Exception property to determine whether an exception
    ' occurred during the update operation.
    If e.Exception Is Nothing Then
    
      ' Sometimes an error might occur that does not raise an 
      ' exception, but prevents the update operation from 
      ' completing. Use the AffectedRows property to determine 
      ' whether the record was actually updated. 
      If e.AffectedRows = 1 Then
      
        ' Use the Keys property to get the value of the key field.
        Dim keyFieldValue As String = e.Keys("CustomerID").ToString()

        ' Display a confirmation message.
        Message.Text = "Record " & keyFieldValue & _
          " updated successfully. "

        ' Display the new and original values.
        DisplayValues(CType(e.NewValues, OrderedDictionary), CType(e.OldValues, OrderedDictionary))

      Else
      
        ' Display an error message.
        Message.Text = "An error occurred during the update operation."

        ' When an error occurs, keep the GridView
        ' control in edit mode.
        e.KeepInEditMode = True
        
      End If
    
    Else
    
      ' Insert the code to handle the exception.
      Message.Text = e.Exception.Message

      ' Use the ExceptionHandled property to indicate that the 
      ' exception is already handled.
      e.ExceptionHandled = True

      e.KeepInEditMode = True
    
    End If
  
  End Sub

  Sub DisplayValues(ByVal newValues As OrderedDictionary, ByVal oldValues As OrderedDictionary)

    Message.Text &= "<br/></br>"

    ' Iterate through the new and old values. Display the
    ' values on the page.
    Dim i As Integer
    For i = 0 To oldValues.Count - 1
    
      Message.Text &= "Old Value=" & oldValues(i).ToString() & _
        ", New Value=" & newValues(i).ToString() & "<br/>"
    Next

    Message.Text &= "</br>"

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewUpdatedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewUpdatedEventArgs Example</h3>
            
      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames property as read-only.    -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogenerateeditbutton="true"
        allowpaging="true" 
        datakeynames="CustomerID"
        onrowupdated="CustomersGridView_RowUpdated" 
        runat="server">
      </asp:gridview>
      
      <br/>
      
      <asp:label id="Message"
        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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

Uwagi

Użyj właściwości , OldValues aby uzyskać dostęp do oryginalnych wartości pól dla zaktualizowanego rekordu. Możesz na przykład użyć tych wartości, aby przechowywać dziennik zaktualizowanych rekordów.

Właściwość OldValues zwraca obiekt implementujący System.Collections.Specialized.IOrderedDictionary interfejs. Obiekt zawiera System.Collections.DictionaryEntry obiekty reprezentujące pola zaktualizowanego rekordu z ich oryginalnymi wartościami.

Uwaga

Skrót umożliwia również bezpośredni dostęp do wartości pól za pomocą indeksatora IOrderedDictionary obiektu.

Dotyczy

GridViewUpdatedEventArgs.OldValues Właściwość

Definicja

Wartość właściwości

Przykłady

Uwagi

Dotyczy

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