DataControlField.Visible Proprietà

Definizione

Spazio dei nomi:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Ottiene o imposta un valore che indica se viene eseguito il rendering di un campo di controllo dati.Gets or sets a value indicating whether a data control field is rendered.

public:
 property bool Visible { bool get(); void set(bool value); };
public bool Visible { get; set; }
member this.Visible : bool with get, set
Public Property Visible As Boolean

Valore della proprietà

Boolean

true se DataControlField viene sottoposto a rendering; in caso contrario, false.true if the DataControlField is rendered; otherwise, false. Il valore predefinito è true.The default value is true.

Esempio

Nell'esempio di codice riportato di seguito viene illustrato come utilizzare BoundField e ButtonField oggetti, derivati da DataControlField, per visualizzare le righe in un controllo DetailsView.The following code example demonstrates how to use BoundField and ButtonField objects, which are derived from DataControlField, to display rows in a DetailsView control. La proprietà Visible dell'oggetto BoundField che visualizza la colonna EmployeeID è impostata su falsee il rendering della colonna non viene eseguito dal controllo DetailsView.The Visible property of the BoundField object that displays the EmployeeID column is set to false, and the column is not rendered by the DetailsView control.

<%@ page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
  <form id="form1" runat="server">
    <asp:detailsview
      id="DetailsView1"
      runat="server"
      allowpaging="True"
      datasourceid="SqlDataSource1"
      autogeneraterows="False"
      width="312px"
      height="152px">
        <fields>
          <asp:boundfield
            visible="False"
            sortexpression="EmployeeID"
            datafield="EmployeeID">
          </asp:boundfield>

          <asp:boundfield
            sortexpression="LastName"
            datafield="LastName"
            headertext="LastName">
          </asp:boundfield>

          <asp:boundfield
            sortexpression="FirstName"
            datafield="FirstName"
            headertext="FirstName">
          </asp:boundfield>

          <asp:boundfield
            sortexpression="Title"
            datafield="Title"
            headertext="Title">
          </asp:boundfield>

          <asp:buttonfield text="Button">
            <controlstyle font-bold="True" forecolor="Red" />
          </asp:buttonfield>
        </fields>
    </asp:detailsview>

    <asp:sqldatasource
      id="SqlDataSource1"
      runat="server"
      selectcommand="SELECT * FROM Employees"
      connectionstring="<%$ ConnectionStrings:MyNorthwind%>">
    </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">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
  <form id="form1" runat="server">
    <asp:detailsview
      id="DetailsView1"
      runat="server"
      allowpaging="True"
      datasourceid="SqlDataSource1"
      autogeneraterows="False"
      width="312px"
      height="152px">
        <fields>
          <asp:boundfield
            visible="False"
            sortexpression="EmployeeID"
            datafield="EmployeeID">
          </asp:boundfield>

          <asp:boundfield
            sortexpression="LastName"
            datafield="LastName"
            headertext="LastName">
          </asp:boundfield>

          <asp:boundfield
            sortexpression="FirstName"
            datafield="FirstName"
            headertext="FirstName">
          </asp:boundfield>

          <asp:boundfield
            sortexpression="Title"
            datafield="Title"
            headertext="Title">
          </asp:boundfield>

          <asp:buttonfield text="Button">
            <controlstyle font-bold="True" forecolor="Red" />
          </asp:buttonfield>
        </fields>
    </asp:detailsview>

    <asp:sqldatasource
      id="SqlDataSource1"
      runat="server"
      selectcommand="SELECT * FROM Employees"
      connectionstring="<%$ ConnectionStrings:MyNorthwind%>">
    </asp:sqldatasource>

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

Commenti

Utilizzare la proprietà Visible per mostrare o nascondere DataControlField oggetti in un controllo con associazione a dati.Use the Visible property to show or hide DataControlField objects in a data-bound control.

Se la proprietà Visible è false, i valori dei dati non verranno visualizzati e non verrà eseguita una sequenza di andata e ritorno al client.If the Visible property is false, the data values are not displayed and do not make a round-trip to the client. Se si desidera eseguire il round trip dei dati per un campo non visibile, aggiungere il nome del campo alla proprietà DataKeyNames del controllo associato a dati.If you want to round-trip the data for a field that is not visible, add the field name to the DataKeyNames property of the data-bound control.

Si applica a