GridViewDeletedEventArgs.AffectedRows Vlastnost

Definice

Získá počet řádků ovlivněných operací odstranění.Gets the number of rows affected by the delete operation.

public:
 property int AffectedRows { int get(); };
public int AffectedRows { get; }
member this.AffectedRows : int
Public ReadOnly Property AffectedRows As Integer

Hodnota vlastnosti

Int32

Počet řádků, které ovlivnila operace odstraněníThe number of rows affected by the delete operation.

Příklady

Následující příklad ukazuje, jak použít AffectedRows vlastnost k ověření, že záznam byl odstraněn během operace odstranění.The following example demonstrates how to use the AffectedRows property to verify that a record was deleted during the delete operation.


<%@ 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_RowDeleted(Object sender, GridViewDeletedEventArgs e)
  {

    // Use the Exception property to determine whether an exception
    // occurred during the delete operation.
    if (e.Exception == null)
    {
      // Use the AffectedRows property to determine whether the
      // record was deleted. Sometimes an error might occur that 
      // does not raise an exception, but prevents the delete
      // operation from completing.
      if (e.AffectedRows == 1)
      {
        Message.Text = "Record deleted successfully.";
      }
      else
      {
        Message.Text = "An error occurred during the delete operation.";
      }
    }
    else
    {
      // Insert the code to handle the exception.
      Message.Text = "An error occurred during the delete operation.";

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

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewDeletedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewDeletedEventArgs Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"          
        runat="server"/>
                
      <br/>
            
      <!-- 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"
        autogeneratedeletebutton="true"
        datakeynames="CustomerID"
        onrowdeleted="CustomersGridView_RowDeleted"  
        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" %>

<!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_RowDeleted(ByVal sender As Object, ByVal e As GridViewDeletedEventArgs)

    ' Use the Exception property to determine whether an exception
    ' occurred during the delete operation.
    If e.Exception Is Nothing Then

      ' Use the AffectedRows property to determine whether the
      ' record was deleted. Sometimes an error might occur that 
      ' does not raise an exception, but prevents the delete
      ' operation from completing.
      If e.AffectedRows = 1 Then
      
        Message.Text = "Record deleted successfully."
      
      Else
      
        Message.Text = "An error occurred during the delete operation."
      
      End If
    
    Else
          
      ' Insert the code to handle the exception.
      Message.Text = "An error occurred during the delete operation."

      ' Use the ExceptionHandled property to indicate that the 
      ' exception is already handled.
      e.ExceptionHandled = True
    
    End If
    
  End Sub
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewDeletedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewDeletedEventArgs Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"          
        runat="server"/>
                
      <br/>
            
      <!-- 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"
        autogeneratedeletebutton="true"
        datakeynames="CustomerID"
        onrowdeleted="CustomersGridView_RowDeleted"  
        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>

Poznámky

Pomocí AffectedRows vlastnosti určíte počet záznamů ovlivněných operací odstranění.Use the AffectedRows property to determine the number of records affected by the delete operation. Tato vlastnost se běžně používá k ověření, že se v následujících situacích odstranil správný počet záznamů:This property is commonly used to verify that the correct number of records was deleted in the following situations:

  • Ověřte, že byl odstraněn pouze jeden záznam.Verify that only a single record was deleted. Nesprávně napsaný příkaz DELETE může někdy odstranit několik záznamů.Sometimes an improperly written delete statement can delete multiple records.

  • Ověřte, že záznam byl odstraněn, když během operace odstranění dojde k chybě, která nevyvolala výjimku.Verify that a record was deleted when an error occurs during the delete operation that does not raise an exception.

  • Ověřte, že záznam byl odstraněn, když ovládací prvek zdroje dat, který podporuje optimistickou souběžnost ( SqlDataSource například ObjectDataSource ovládací prvky a), má svou ConflictDetection vlastnost nastavenou na ConflictOptions.CompareAllValues hodnotu výčtu.Verify that a record was deleted when a data source control that supports optimistic concurrency (such as the SqlDataSource and ObjectDataSource controls) has its ConflictDetection property set to the ConflictOptions.CompareAllValues enumeration value. V rámci tohoto nastavení nemusí být záznam, který byl současně pozměněn jiným uživatelem, odstraněn.Under this setting, a record that has been modified by another user concurrently might not be deleted.

Platí pro

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