DataControlRowType Enumerazione

  • Riferimento

Definizione

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

Specifica la funzione di una riga in un controllo dati, ad esempio un controllo DetailsView o GridView.

public enum class DataControlRowType
public enum DataControlRowType
type DataControlRowType = 
Public Enum DataControlRowType
Ereditarietà
Object
ValueType
Enum
DataControlRowType

Campi

DataRow 2

Riga di dati di un controllo dati. Soltanto le righe DataRow possono essere con associazione a dati.
EmptyDataRow 5

Riga vuota di un controllo con associazione a dati. La riga vuota viene visualizzata quando non vi sono record da visualizzare nel controllo con associazione a dati e il modello EmptyDataTemplate non è null.
1

Riga del piè di pagina di un controllo dati. Le righe del piè di pagina non possono essere con associazione a dati.
Header 0

Riga di intestazione di un controllo dati. Le righe di intestazione non possono essere con associazione a dati.
Pager 4

Riga che visualizza i pulsanti pager o un controllo pager. Le righe di spostamento non possono essere con associazione a dati.
Separator 3

Separatore di righe. I separatori di righe non possono essere con associazione a dati.

Esempio

Nell'esempio di codice seguente viene illustrato come usare l'enumerazione per controllare il DataControlRowType tipo di una riga quando si usa un GridView controllo. Il AuthorsGridView_RowCreated metodo garantisce che la CommandArgument proprietà di un controllo sia univoca per tutte le righe di dati nel GridView controllo, in modo che, quando viene fatto clic sul controllo di LinkButton una LinkButton riga, può essere identificata correttamente.


<%@ 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>GridViewCommandEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>GridViewCommandEventArgs 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>GridViewCommandEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>GridViewCommandEventArgs 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>

Commenti

L'enumerazione DataControlRowType identifica la funzione delle righe in un controllo dati. Viene usato dai DetailsView controlli e GridView per distinguere tra righe che visualizzano dati e righe che visualizzano altri elementi dell'interfaccia utente, ad esempio una riga di intestazione, un separatore di righe o pulsanti di pager.

È possibile usare l'enumerazione DataControlRowType per identificare il tipo di un GridViewRow oggetto o DetailsViewRow quando si enumera tramite una GridViewRowCollection o DetailsViewRowCollection raccolta. Se si scrive un controllo dati che crea righe, è possibile usare l'enumerazione DataControlRowType per identificare la funzione di righe diverse nel controllo.

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