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GridViewUpdateEventHandler Делегат

Определение

Представляет метод, обрабатывающий событие RowUpdating элемента управления GridView.

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

Параметры

sender
Object

Источник события.

e
GridViewUpdateEventArgs

Объект GridViewUpdateEventArgs, содержащий данные события.

Примеры

В следующем примере показано, как программным способом GridViewUpdateEventHandler добавить делегат в RowUpdating событие GridView элемента управления .


<%@ 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 Page_Load(Object sender, EventArgs e)
    {
        
        // Create a new GridView object.
        GridView authorGridView = new GridView();
         
        // Set the GridView object's properties.
        authorGridView.ID = "AuthorGridView";
        authorGridView.DataSourceID = "AuthorsSqlDataSource"; 
        authorGridView.AutoGenerateColumns = true;
        authorGridView.AutoGenerateEditButton = true;
        authorGridView.DataKeyNames = new String[] {"au_id"};
        
        // Programmatically register the event-handling method.
        authorGridView.RowUpdating += new GridViewUpdateEventHandler(this.AuthorsGridView_RowUpdating);
        
        // Add the GridView object to the Controls collection
        // of the PlaceHolder control.
        GridViewPlaceHolder.Controls.Add(authorGridView);
        
    }
    
    void AuthorsGridView_RowUpdating(Object sender, GridViewUpdateEventArgs e)
    {
     
        // HTML-encode all user-provided values before updating
        // the data source.
        foreach (DictionaryEntry entry in e.NewValues)
        {
    
            e.NewValues[entry.Key] = Server.HtmlEncode(entry.Value.ToString());
    
        }
        
    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
    <head runat="server">
    <title>GridViewUpdateEventHandler Example</title>
</head>
<body>
        <form id="form1" runat="server">
        
            <h3>GridViewUpdateEventHandler Example</h3>
            
            <asp:label id="Message"
                forecolor="Red"
                runat="server"/>
                
            <br/>
            
            <asp:placeholder id="GridViewPlaceHolder"
                runat="Server"/>
            
            <!-- This example uses Microsoft SQL Server and connects -->
            <!-- to the Pubs sample database.                        -->
            <asp:sqldatasource id="AuthorsSqlDataSource"  
                selectcommand="SELECT [au_id], [au_lname], [au_fname], [address], [city], [state], [zip] FROM [authors]"
                updatecommand="UPDATE authors SET au_lname=@au_lname, au_fname=@au_fname, address=@address, city=@city, state=@state, zip=@zip WHERE (authors.au_id = @au_id)"
                connectionstring="server=localhost;database=pubs;integrated security=SSPI"
                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 Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        
        ' Create a new GridView object.
        Dim authorGridView As GridView = New GridView
         
        ' Set the GridView object's properties.
        authorGridView.ID = "AuthorGridView"
        authorGridView.DataSourceID = "AuthorsSqlDataSource"
        authorGridView.AutoGenerateColumns = True
        authorGridView.AutoGenerateEditButton = True
        authorGridView.DataKeyNames = New [String]() {"au_id"}
        
        ' Programmatically register the event-handling method.
        AddHandler authorGridView.RowUpdating, AddressOf AuthorsGridView_RowUpdating
        
        ' Add the GridView object to the Controls collection
        ' of the PlaceHolder control.
        GridViewPlaceHolder.Controls.Add(authorGridView)
        
    End Sub
    
    Sub AuthorsGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
     
        ' HTML-encode all user-provided values before updating
        ' the data source.
        Dim i As Integer
        
        For i = 0 To e.NewValues.Count - 1
            
            Dim entry As DictionaryEntry = e.NewValues(i)
            e.NewValues(entry.Key) = Server.HtmlEncode(entry.Value.ToString())
    
        Next i
        
    End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
    <head runat="server">
    <title>GridViewUpdateEventHandler Example</title>
</head>
<body>
        <form id="form1" runat="server">
        
            <h3>GridViewUpdateEventHandler Example</h3>
            
            <asp:label id="Message"
                forecolor="Red"
                runat="server"/>
                
            <br/>
            
            <asp:placeholder id="GridViewPlaceHolder"
                runat="Server"/>
            
            <!-- This example uses Microsoft SQL Server and connects -->
            <!-- to the Pubs sample database.                        -->
            <asp:sqldatasource id="AuthorsSqlDataSource"  
                selectcommand="SELECT [au_id], [au_lname], [au_fname], [address], [city], [state], [zip] FROM [authors]"
                updatecommand="UPDATE authors SET au_lname=@au_lname, au_fname=@au_fname, address=@address, city=@city, state=@state, zip=@zip WHERE (authors.au_id = @au_id)"
                connectionstring="server=localhost;database=pubs;integrated security=SSPI"
                runat="server">
            </asp:sqldatasource>
            
        </form>
    </body>
</html>

В следующем примере показано, как декларативно добавить GridViewUpdateEventHandler делегат в RowUpdating событие GridView элемента управления .


<%@ 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_RowUpdating(Object sender, GridViewUpdateEventArgs e)
  {
     
    // Iterate through the NewValues collection and HTML encode all 
    // user-provided values before updating the data source.
    foreach (DictionaryEntry entry in e.NewValues)
    {
    
      e.NewValues[entry.Key] = Server.HtmlEncode(entry.Value.ToString());
    
    }
        
  }
       
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView RowUpdating Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView RowUpdating 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"
        onrowupdating="CustomersGridView_RowUpdating"  
        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]"
        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_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
    
    ' Use the CopyTo method to copy the DictionaryEntry objects in the 
    ' NewValues collection to an array.
    Dim records(e.NewValues.Count - 1) As DictionaryEntry
    e.NewValues.CopyTo(records, 0)
    
    ' Iterate through the array and HTML encode all user-provided values 
    ' before updating the data source.
    Dim entry As DictionaryEntry
    For Each entry In records
            
      e.NewValues(entry.Key) = Server.HtmlEncode(entry.Value.ToString())
      
    Next
        
  End Sub
       
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView RowUpdating Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView RowUpdating 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"
        onrowupdating="CustomersGridView_RowUpdating"  
        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]"
        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>

Комментарии

Событие RowUpdating возникает при нажатии кнопки Обновить строки, но до того, как GridView элемент управления обновит строку. Это позволяет предоставить метод обработки событий, который выполняет пользовательскую подпрограмму, например отмену операции обновления, при каждом возникновении этого события.

При создании делегата GridViewUpdateEventHandler необходимо указать метод, обрабатывающий событие. Чтобы связать событие с обработчиком событий, нужно добавить в событие экземпляр делегата. Обработчик событий вызывается всякий раз, когда происходит событие, если делегат не удален. Дополнительные сведения о делегатах обработчика событий см. в разделе Обработка и вызов событий.

Методы расширения

GetMethodInfo(Delegate)

Получает объект, представляющий метод, представленный указанным делегатом.

Применяется к

См. также раздел