ButtonField Constructor ()

 

Initializes a new instance of the ButtonField class.

Namespace:   System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

Public Sub New

Use the ButtonField constructor to initialize a new instance of the ButtonField class. This constructor is commonly used when adding fields to a dynamically created data-bound control.

To add a ButtonField object dynamically to a data-bound control, create a new ButtonField object, set its properties, and then add it to the field collection for the data-bound control. For example, if you are using the GridView control, add the ButtonField object to the Columns collection.

System_CAPS_noteNote

Although you can add fields dynamically to a data-bound control, fields should be declared statically, and then shown or hidden, as appropriate. Statically declaring all of your fields reduces the size of the view state for the parent data-bound control.

The following code example demonstrates how to use the M:System.Web.UI.WebControls.ButtonField.#ctor constructor to add a ButtonField object dynamically to a GridView control.


<%@ 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>

.NET Framework
Available since 2.0
Return to top
Show: