ButtonField Konstruktor

  • Referenz

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Initialisiert eine neue Instanz der ButtonField-Klasse.

public:
 ButtonField();
public ButtonField ();
Public Sub New ()

Beispiele

Im folgenden Codebeispiel wird veranschaulicht, wie Sie den M:System.Web.UI.WebControls.ButtonField.#ctor-Konstruktor verwenden, um einem GridView Steuerelement ein ButtonField Objekt dynamisch hinzuzufügen.


<%@ 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_RowCommand(Object sender, GridViewCommandEventArgs e)
  {
  
    // If multiple ButtonField column fields are used, use the
    // CommandName property to determine which button was clicked.
    if(e.CommandName=="Select")
    {
    
      // Convert the row index stored in the CommandArgument
      // property to an Integer.
      int index = Convert.ToInt32(e.CommandArgument);    
    
      // Get the last name of the selected Customer from the appropriate
      // cell in the GridView control.
      GridViewRow selectedRow = CustomersGridView.Rows[index];
      TableCell contactCell = selectedRow.Cells[1];
      string contact = contactCell.Text;  
    
      // Display the selected Customer.
      Message.Text = "You selected " + contact + ".";
      
    }
    
  }

  void Page_Load(Object sender, EventArgs e)
  {
  
    // The field columns need to be created only the first time
    // the page is loaded.
    if (!IsPostBack)
    {
      
      // Dynamically create field columns to display the desired
      // fields from the data source.
      
      // Create a ButtonField object to allow the user to 
      // select an Customer.
      ButtonField selectButtonField = new ButtonField ();

      selectButtonField.ButtonType = ButtonType.Button;
      selectButtonField.CommandName = "Select";
      selectButtonField.HeaderText = "Select Customer";
      selectButtonField.Text = "Select";

      // Create a BoundField object to display an Customer's last name.
      BoundField contactNameBoundField = new BoundField();

      contactNameBoundField.DataField = "ContactName";
      contactNameBoundField.HeaderText = "Contact Name";

      // Create a BoundField object to display an Customer's first name.
      BoundField contactTitleBoundField = new BoundField();

      contactTitleBoundField.DataField = "ContactTitle";
      contactTitleBoundField.HeaderText = "Contact Title";

      // Add the field columns to the Columns collection of the
      // GridView control.
      CustomersGridView.Columns.Add (selectButtonField);
      CustomersGridView.Columns.Add(contactNameBoundField);
      CustomersGridView.Columns.Add(contactTitleBoundField);
      
    }
    
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ButtonField Constructor Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>ButtonField Constructor Example</h3>

      <asp:label id="Message"
        forecolor="Red"
        runat="server"
        AssociatedControlID="CustomersGridView"/>

      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="False"
        onrowcommand="CustomersGridView_RowCommand"
        runat="server">                
      </asp:gridview>
            
        <!-- This example uses Microsoft SQL Server and connects -->
        <!-- to the Northwind sample database.                   -->
        <asp:sqldatasource id="CustomersSqlDataSource"  
          selectcommand="Select [CustomerID], [CompanyName], [ContactName], [ContactTitle] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthWindConnection%>"
          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_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs)
  
        ' If multiple ButtonField column fields are used, use the
        ' CommandName property to determine which button was clicked.
        If e.CommandName = "Select" Then
    
            ' Convert the row index stored in the CommandArgument
            ' property to an Integer.
            Dim index As Integer = Convert.ToInt32(e.CommandArgument)
    
            ' Get the last name of the selected Customer from the appropriate
            ' cell in the GridView control.
            Dim selectedRow As GridViewRow = CustomersGridView.Rows(index)
            Dim contactNameCell As TableCell = selectedRow.Cells(1)
            Dim contactName As String = contactNameCell.Text
    
            ' Display the selected Customer.
            Message.Text = "You selected " & contactName & "."
      
        End If
    
    End Sub

    Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
  
        ' The field columns need to be created only the first time
        ' the page is loaded.
        If Not IsPostBack Then
      
            ' Dynamically create field columns to display the desired
            ' fields from the data source.
      
            ' Create a ButtonField object to allow the user to 
            ' select an Customer.
            Dim selectButtonField As New ButtonField

            selectButtonField.ButtonType = ButtonType.Button
            selectButtonField.CommandName = "Select"
            selectButtonField.HeaderText = "Select Customer"
            selectButtonField.Text = "Select"

            ' Create a BoundField object to display an Customer's last name.
            Dim contactNameBoundField As New BoundField

            contactNameBoundField.DataField = "ContactName"
            contactNameBoundField.HeaderText = "Contact Name"

            ' Create a BoundField object to display an Customer's first name.
            Dim contactTitleBoundField As New BoundField

            contactTitleBoundField.DataField = "ContactTitle"
            contactTitleBoundField.HeaderText = "Contact Title"

            ' Add the field columns to the Columns collection of the
            ' GridView control.
            CustomersGridView.Columns.Add(selectButtonField)
            CustomersGridView.Columns.Add(contactNameBoundField)
            CustomersGridView.Columns.Add(contactTitleBoundField)
      
        End If
    
    End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ButtonField Constructor Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>ButtonField Constructor Example</h3>

      <asp:label id="Message"
        forecolor="Red"
        runat="server"
        AssociatedControlID="CustomersGridView"/>

      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="False"
        onrowcommand="CustomersGridView_RowCommand"
        runat="server">                
      </asp:gridview>
            
        <!-- This example uses Microsoft SQL Server and connects -->
        <!-- to the Northwind sample database.                   -->
        <asp:sqldatasource id="CustomersSqlDataSource"  
          selectcommand="Select [CustomerID], [CompanyName], [ContactName], [ContactTitle] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthWindConnection%>"
          runat="server">
        </asp:sqldatasource>
            
    </form>
  </body>
</html>

Hinweise

Verwenden Sie den ButtonField Konstruktor, um eine neue Instanz der ButtonField -Klasse zu initialisieren. Dieser Konstruktor wird häufig beim Hinzufügen von Feldern zu einem dynamisch erstellten datengebundenen Steuerelement verwendet.

Um einem datengebundenen Steuerelement ein ButtonField Objekt dynamisch hinzuzufügen, erstellen Sie ein neues ButtonField Objekt, legen seine Eigenschaften fest, und fügen Sie es dann der Feldauflistung für das datengebundene Steuerelement hinzu. Wenn Sie z. B. das GridView -Steuerelement verwenden, fügen Sie das ButtonField -Objekt der Columns Auflistung hinzu.

Hinweis

Obwohl Sie Felder einem datengebundenen Steuerelement dynamisch hinzufügen können, sollten Felder statisch deklariert und dann nach Bedarf angezeigt oder ausgeblendet werden. Durch das statische Deklarieren aller Felder wird die Größe des Ansichtszustands für das übergeordnete datengebundene Steuerelement verringert.

Gilt für:

Weitere Informationen