GridViewCommandEventHandler Делегат

Определение

Представляет метод, обрабатывающий событие RowCommand элемента управления GridView.Represents the method that handles the RowCommand event of a GridView control.

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

Параметры

sender
Object

Источник события.The source of the event.

e
GridViewCommandEventArgs

Объект GridViewCommandEventArgs, содержащий данные события.A GridViewCommandEventArgs object that contains the event data.

Наследование
GridViewCommandEventHandler

Примеры

В следующем примере показано, как программным способом GridViewCommandEventHandler добавить делегат RowCommand к событию GridView элемента управления.The following example demonstrates how to programmatically add a GridViewCommandEventHandler delegate to the RowCommand event of a GridView control.


<%@ 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 customersGridView = new GridView();

    // Set the GridView object's properties.
    customersGridView.ID = "CustomersGridView";
    customersGridView.DataSourceID = "CustomersSource";
    customersGridView.AutoGenerateColumns = false;

    // Dynamically create the columns for the GridView control.
    ButtonField addColumn = new ButtonField();
    addColumn.CommandName = "Add";
    addColumn.Text = "Add";
    addColumn.ButtonType = ButtonType.Link;

    BoundField companyNameColumn = new BoundField();
    companyNameColumn.DataField = "CompanyName";
    companyNameColumn.HeaderText = "Company Name";

    BoundField cityColumn = new BoundField();
    cityColumn.DataField = "City";
    cityColumn.HeaderText = "City";

    // Add the columns to the Columns collection
    // of the GridView control.
    customersGridView.Columns.Add(addColumn);
    customersGridView.Columns.Add(companyNameColumn);
    customersGridView.Columns.Add(cityColumn);

    // Programmatically register the event handling methods.
    customersGridView.RowCommand += new GridViewCommandEventHandler(this.CustomersGridView_RowCommand);
    customersGridView.RowCreated += new GridViewRowEventHandler(this.CustomersGridView_RowCreated);

    // Add the GridView object to the Controls collection
    // of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customersGridView);

  }

  void CustomersGridView_RowCommand(Object sender, GridViewCommandEventArgs e)
  {
    // If multiple ButtonField columns are used, use the
    // CommandName property to determine which button was clicked.
    if(e.CommandName=="Add")
    {
      // Convert the row index stored in the CommandArgument
      // property to an Integer.
      int index = Convert.ToInt32(e.CommandArgument);

      // Retrieve the row that contains the button clicked
      // by the user from the Rows collection. Use the
      // CommandSource property to access the GridView control.
      GridView customersGridView = (GridView)e.CommandSource;
      GridViewRow row = customersGridView.Rows[index];

      // Create a new ListItem object for the customer in the row.
      ListItem item = new ListItem();
      item.Text = Server.HtmlDecode(row.Cells[1].Text) + " " + Server.HtmlDecode(row.Cells[2].Text);

      // If the author is not already in the ListBox, add the ListItem
      // object to the Items collection of a ListBox control.
      if(!CustomersListBox.Items.Contains(item))
      {
        CustomersListBox.Items.Add(item);
      }
    }
  }

  void CustomersGridView_RowCreated(Object sender, GridViewRowEventArgs e)
  {

    // The GridViewCommandEventArgs class does not contain a
    // property that indicates which row's command button was
    // clicked. To identify which row was clicked, use the button's
    // CommandArgument property by setting it to the row's index.
    if(e.Row.RowType == DataControlRowType.DataRow)
    {
      // Retrieve the LinkButton control from the first column.
      LinkButton addButton = (LinkButton)e.Row.Cells[0].Controls[0];

      // Set the LinkButton's CommandArgument property with the
      // row's index.
      addButton.CommandArgument = e.Row.RowIndex.ToString();
    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewCommandEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>GridViewCommandEventHandler Example</h3>

      <table width="100%">
        <tr>
          <td style="width:50%">
            <asp:placeholder id="GridViewPlaceHolder"
              runat="Server"/>
          </td>

          <td style="vertical-align:top; width:50%">
             Customers: <br/>
             <asp:listbox id="CustomersListBox"
               runat="server"/>
          </td>
        </tr>
      </table>

      <!-- 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="CustomersSource"
        selectcommand="Select [CustomerID], [CompanyName], [City] From [Customers]"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>

    </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 customersGridView As New GridView()

    ' Set the GridView object's properties.
    customersGridView.ID = "CustomersGridView"
    customersGridView.DataSourceID = "CustomersSource"
    customersGridView.AutoGenerateColumns = False

    ' Dynamically create the columns for the GridView control.
    Dim addColumn As New ButtonField()
    addColumn.CommandName = "Add"
    addColumn.Text = "Add"
    addColumn.ButtonType = ButtonType.Link

    Dim companyNameColumn As New BoundField()
    companyNameColumn.DataField = "CompanyName"
    companyNameColumn.HeaderText = "Company Name"

    Dim cityColumn As New BoundField()
    cityColumn.DataField = "City"
    cityColumn.HeaderText = "City"

    ' Add the columns to the Columns collection
    ' of the GridView control.
    customersGridView.Columns.Add(addColumn)
    customersGridView.Columns.Add(companyNameColumn)
    customersGridView.Columns.Add(cityColumn)

    ' Programmatically register the event handling methods.
    AddHandler customersGridView.RowCommand, AddressOf CustomersGridView_RowCommand
    AddHandler customersGridView.RowCreated, AddressOf CustomersGridView_RowCreated

    ' Add the GridView object to the Controls collection
    ' of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customersGridView)

  End Sub

  Sub CustomersGridView_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs)
  
    ' If multiple ButtonField columns are used, use the
    ' CommandName property to determine which button was clicked.
    If e.CommandName = "Add" Then
    
      ' Convert the row index stored in the CommandArgument
      ' property to an Integer.
      Dim index As Integer = Convert.ToInt32(e.CommandArgument)

      ' Retrieve the row that contains the button clicked
      ' by the user from the Rows collection. Use the
      ' CommandSource property to access the GridView control.
      Dim customersGridView As GridView = CType(e.CommandSource, GridView)
      Dim row As GridViewRow = customersGridView.Rows(index)

      ' Create a new ListItem object for the customer in the row.
      Dim item As New ListItem()
      item.Text = Server.HtmlDecode(row.Cells(1).Text) + " " + Server.HtmlDecode(row.Cells(2).Text)

      ' If the author is not already in the ListBox, add the ListItem
      ' object to the Items collection of a ListBox control.
      If Not CustomersListBox.Items.Contains(item) Then
      
        CustomersListBox.Items.Add(item)
        
      End If
    End If
        
  End Sub

  Sub CustomersGridView_RowCreated(ByVal sender As Object, ByVal e As GridViewRowEventArgs)

    ' The GridViewCommandEventArgs class does not contain a
    ' property that indicates which row's command button was
    ' clicked. To identify which row was clicked, use the button's
    ' CommandArgument property by setting it to the row's index.
    If e.Row.RowType = DataControlRowType.DataRow Then

      ' Retrieve the LinkButton control from the first column.
      Dim addButton As LinkButton = CType(e.Row.Cells(0).Controls(0), LinkButton)

      ' Set the LinkButton's CommandArgument property with the
      ' row's index.
      addButton.CommandArgument = e.Row.RowIndex.ToString()
      
    End If

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewCommandEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>GridViewCommandEventHandler Example</h3>

      <table width="100%">
        <tr>
          <td style="width:50%">
            <asp:placeholder id="GridViewPlaceHolder"
              runat="Server"/>
          </td>

          <td style="vertical-align:top; width:50%">
             Customers: <br/>
             <asp:listbox id="CustomersListBox"
               runat="server"/>
          </td>
        </tr>
      </table>

      <!-- 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="CustomersSource"
        selectcommand="Select [CustomerID], [CompanyName], [City] From [Customers]"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>

    </form>
  </body>
</html>

В следующем примере показано, как декларативно добавить GridViewCommandEventHandler делегат RowCommand к событию GridView элемента управления.The following example demonstrates how to declaratively add a GridViewCommandEventHandler delegate to the RowCommand event of a GridView control.


<%@ 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 ContactsGridView_RowCommand(Object sender, GridViewCommandEventArgs e)
  {
    // If multiple buttons are used in a GridView control, use the
    // CommandName property to determine which button was clicked.
    if(e.CommandName=="Add")
    {
      // Convert the row index stored in the CommandArgument
      // property to an Integer.
      int index = Convert.ToInt32(e.CommandArgument);

      // Retrieve the row that contains the button clicked 
      // by the user from the Rows collection.
      GridViewRow row = ContactsGridView.Rows[index];

      // Create a new ListItem object for the contact in the row.     
      ListItem item = new ListItem();
      item.Text = Server.HtmlDecode(row.Cells[2].Text) + " " +
        Server.HtmlDecode(row.Cells[3].Text);

      // If the contact is not already in the ListBox, add the ListItem 
      // object to the Items collection of the ListBox control. 
      if (!ContactsListBox.Items.Contains(item))
      {
        ContactsListBox.Items.Add(item);
      }
    }
  }    
</script>

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

      <h3>GridView RowCommand Example</h3>

      <table width="100%">
        <tr>
          <td style="width:50%">

            <asp:gridview id="ContactsGridView" 
              datasourceid="ContactsSource"
              allowpaging="true" 
              autogeneratecolumns="false"
              onrowcommand="ContactsGridView_RowCommand"
              runat="server">

              <columns>
                <asp:buttonfield buttontype="Link" 
                  commandname="Add" 
                  text="Add"/>
                <asp:boundfield datafield="ContactID" 
                  headertext="Contact ID"/>
                <asp:boundfield datafield="FirstName" 
                  headertext="First Name"/> 
                <asp:boundfield datafield="LastName" 
                  headertext="Last Name"/>
              </columns>

            </asp:gridview>

          </td>

          <td style="vertical-align:top; width:50%">

            Contacts: <br/>
            <asp:listbox id="ContactsListBox"
              runat="server" Height="200px" Width="200px"/>

          </td>
        </tr>
      </table>

      <!-- This example uses Microsoft SQL Server and connects    -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET  -->
      <!-- expression to retrieve the connection string value     -->
      <!-- from the Web.config file.                              -->
      <asp:sqldatasource id="ContactsSource"
        selectcommand="Select [ContactID], [FirstName], [LastName] From Person.Contact"
        connectionstring="<%$ ConnectionStrings:AdventureWorks_DataConnectionString%>" 
        runat="server"/>

    </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 ContactsGridView_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs)

    ' If multiple buttons are used in a GridView control, use the
    ' CommandName property to determine which button was clicked.
    If e.CommandName = "Add" Then
    
      ' Convert the row index stored in the CommandArgument
      ' property to an Integer.
      Dim index As Integer = Convert.ToInt32(e.CommandArgument)
            
      ' Retrieve the row that contains the button clicked 
      ' by the user from the Rows collection.
      Dim row As GridViewRow = ContactsGridView.Rows(index)
            
      ' Create a new ListItem object for the contact in the row.     
      Dim item As New ListItem()
      item.Text = Server.HtmlDecode(row.Cells(2).Text) & " " & _
        Server.HtmlDecode(row.Cells(3).Text)
            
      ' If the contact is not already in the ListBox, add the ListItem 
      ' object to the Items collection of the ListBox control. 
      If Not ContactsListBox.Items.Contains(item) Then
      
        ContactsListBox.Items.Add(item)
        
      End If
      
    End If
    
  End Sub
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>GridView RowCommand Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>GridView RowCommand Example</h3>

      <table width="100%">
        <tr>
          <td style="width:50%">

            <asp:gridview id="ContactsGridView" 
              datasourceid="ContactsSource"
              allowpaging="true" 
              autogeneratecolumns="false"
              onrowcommand="ContactsGridView_RowCommand"
              runat="server">

              <columns>
                <asp:buttonfield buttontype="Link" 
                  commandname="Add" 
                  text="Add"/>
                <asp:boundfield datafield="ContactID" 
                  headertext="Contact ID"/>
                <asp:boundfield datafield="FirstName" 
                  headertext="First Name"/> 
                <asp:boundfield datafield="LastName" 
                  headertext="Last Name"/>
              </columns>

            </asp:gridview>

          </td>

          <td style="vertical-align:top; width:50%">

            Contacts: <br/>
            <asp:listbox id="ContactsListBox"
              runat="server" Height="200px" Width="200px"/>

          </td>
        </tr>
      </table>

      <!-- This example uses Microsoft SQL Server and connects    -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET  -->
      <!-- expression to retrieve the connection string value     -->
      <!-- from the Web.config file.                              -->
      <asp:sqldatasource id="ContactsSource"
        selectcommand="Select [ContactID], [FirstName], [LastName] From Person.Contact"
        connectionstring="<%$ ConnectionStrings:AdventureWorks_DataConnectionString%>" 
        runat="server"/>

    </form>
  </body>
</html>

Комментарии

Событие возникает при нажатии кнопки GridView в элементе управления. RowCommandThe RowCommand event is raised when a button within the GridView control is clicked. Это позволяет предоставить метод обработки событий, который выполняет пользовательскую подпрограммы при возникновении этого события.This allows you to provide an event-handling method that performs a custom routine whenever this event occurs.

Примечание

Элемент управления также вызывает другие специализированные события при нажатии определенных кнопок (кнопки CommandName со свойством, для которых задано значение "Удалить", "Обновить" и "страница", например). GridViewThe GridView control also raises other specialized events when certain buttons are clicked (buttons with the CommandName property set to "Delete", "Update", and "Page" for example). При использовании одной из этих кнопок следует рассмотреть возможность обработки одного из специализированных событий, предоставляемых элементом управления (например RowDeleted , или RowDeleting).When using one of these buttons, you should consider handling one of the specialized events provided by the control (such as RowDeleted or RowDeleting).

При создании делегата GridViewCommandEventHandler необходимо указать метод, обрабатывающий событие.When you create a GridViewCommandEventHandler delegate, you identify the method that will handle the event. Чтобы связать событие с обработчиком событий, нужно добавить в событие экземпляр делегата.To associate the event with your event handler, add an instance of the delegate to the event. Обработчик событий вызывается всякий раз, когда происходит событие, если делегат не удален.The event handler is called whenever the event occurs, unless you remove the delegate. Дополнительные сведения о делегатах обработчиков событий см. в разделе обработка и вызов событий.For more information about event-handler delegates, see Handling and Raising Events.

Методы расширения

GetMethodInfo(Delegate)

Получает объект, представляющий метод, представленный указанным делегатом.Gets an object that represents the method represented by the specified delegate.

Применяется к

Дополнительно