ListView.Clear Metodo

Definizione

Spazio dei nomi:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Rimuove tutti gli elementi e tutte le colonne dal controllo.

public:
 void Clear();

public void Clear ();

member this.Clear : unit -> unit

Public Sub Clear ()

Esempio

Nell'esempio di codice seguente viene illustrato l'uso di Clear e ListViewItem.Selected membri. Per eseguire questo esempio, incollare il codice seguente in un modulo contenente un ListView pulsante denominato e un pulsante, situato verso la parte inferiore del modulo, denominato Button1ListView1 . Chiamare il InitializeListView metodo dal costruttore o Load dal metodo del modulo.

private:
   void InitializeListView()
   {
      // Set up the inital values for the ListView and populate it.
      this->ListView1 = gcnew ListView;
      this->ListView1->Dock = DockStyle::Top;
      this->ListView1->Location = System::Drawing::Point( 0, 0 );
      this->ListView1->Size = System::Drawing::Size( 292, 130 );
      this->ListView1->View = View::Details;
      this->ListView1->FullRowSelect = true;
      array<String^>^breakfast = {"Continental Breakfast","Pancakes and Sausage","Denver Omelet","Eggs & Bacon","Bagel & Cream Cheese"};
      array<String^>^breakfastPrices = {"3.09","4.09","4.19","4.79","2.09"};
      PopulateMenu( "Breakfast", breakfast, breakfastPrices );
   }

   void PopulateMenu( String^ meal, array<String^>^menuItems, array<String^>^menuPrices )
   {
      ColumnHeader^ columnHeader1 = gcnew ColumnHeader;
      columnHeader1->Text = String::Concat( meal, " Choices" );
      columnHeader1->TextAlign = HorizontalAlignment::Left;
      columnHeader1->Width = 146;
      ColumnHeader^ columnHeader2 = gcnew ColumnHeader;
      columnHeader2->Text = "Price";
      columnHeader2->TextAlign = HorizontalAlignment::Center;
      columnHeader2->Width = 142;
      this->ListView1->Columns->Add( columnHeader1 );
      this->ListView1->Columns->Add( columnHeader2 );
      for ( int count = 0; count < menuItems->Length; count++ )
      {
         ListViewItem^ listItem = gcnew ListViewItem( menuItems[ count ] );
         listItem->SubItems->Add( menuPrices[ count ] );
         ListView1->Items->Add( listItem );

      }
      
      // Use the Selected property to select the first item on 
      // the list.
      ListView1->Focus();
      ListView1->Items[ 0 ]->Selected = true;
   }

   void Button1_Click( System::Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Create new values for the ListView, clear the list, 
      // and repopulate it.
      array<String^>^lunch = {"Hamburger","Grilled Cheese","Soup & Salad","Club Sandwich","Hotdog"};
      array<String^>^lunchPrices = {"4.09","5.09","5.19","4.79","2.09"};
      ListView1->Clear();
      PopulateMenu( "Lunch", lunch, lunchPrices );
      Button1->Enabled = false;
   }

private void InitializeListView()
{
    // Set up the inital values for the ListView and populate it.
    this.ListView1 = new ListView();
    this.ListView1.Dock = DockStyle.Top;
    this.ListView1.Location = new System.Drawing.Point(0, 0);
    this.ListView1.Size = new System.Drawing.Size(292, 130);
    this.ListView1.View = View.Details;
    this.ListView1.FullRowSelect = true;

    string[] breakfast = new string[]{"Continental Breakfast", 
        "Pancakes and Sausage", "Denver Omelet", "Eggs & Bacon", 
        "Bagel & Cream Cheese"};

    string[] breakfastPrices = new string[]{"3.09", "4.09", 
        "4.19", "4.79", "2.09"};

    PopulateMenu("Breakfast", breakfast, breakfastPrices);
}

private void PopulateMenu(string meal, 
    string[] menuItems, string[] menuPrices)
{
    ColumnHeader columnHeader1 = new ColumnHeader();
    columnHeader1.Text = meal + " Choices";
    columnHeader1.TextAlign = HorizontalAlignment.Left;
    columnHeader1.Width = 146;

    ColumnHeader columnHeader2 = new ColumnHeader();
    columnHeader2.Text = "Price";
    columnHeader2.TextAlign = HorizontalAlignment.Center;
    columnHeader2.Width = 142;

    this.ListView1.Columns.Add(columnHeader1);
    this.ListView1.Columns.Add(columnHeader2);

    for(int count=0; count < menuItems.Length; count++)
    {
        ListViewItem listItem = 
            new ListViewItem(menuItems[count]);
        listItem.SubItems.Add(menuPrices[count]);
        ListView1.Items.Add(listItem);
    }

    // Use the Selected property to select the first item on 
    // the list.
    ListView1.Focus();
    ListView1.Items[0].Selected = true;
}

private void Button1_Click(System.Object sender, System.EventArgs e)
{
    // Create new values for the ListView, clear the list, 
    // and repopulate it.
    string[] lunch = new string[]{"Hamburger", "Grilled Cheese",
        "Soup & Salad", "Club Sandwich", "Hotdog"};

    string[] lunchPrices = new string[]{"4.09", "5.09", "5.19", 
        "4.79", "2.09"};

    ListView1.Clear();

    PopulateMenu("Lunch", lunch, lunchPrices);
    Button1.Enabled = false;
}

Private Sub InitializeListView()

    ' Set up the inital values for the ListView and populate it.
    Me.ListView1 = New ListView
    Me.ListView1.Dock = DockStyle.Top
    Me.ListView1.Location = New System.Drawing.Point(0, 0)
    Me.ListView1.Size = New System.Drawing.Size(292, 130)
    Me.ListView1.View = View.Details
    Me.ListView1.FullRowSelect = True

    Dim breakfast() As String = New String() {"Continental Breakfast", "Pancakes and Sausage", _
   "Denver Omelet", "Eggs & Bacon", "Bagel & Cream Cheese"}

    Dim breakfastPrices() As String = New String() {"3.09", "4.09", "4.19", _
       "4.79", "2.09"}

    PopulateMenu("Breakfast", breakfast, breakfastPrices)
End Sub

Private Sub PopulateMenu(ByVal meal As String, _
    ByVal menuItems() As String, ByVal menuPrices() As String)
    Dim columnHeader1 As New ColumnHeader
    With columnHeader1
        .Text = meal & " Choices"
        .TextAlign = HorizontalAlignment.Left
        .Width = 146
    End With
    Dim columnHeader2 As New ColumnHeader
    With columnHeader2
        .Text = "Price"
        .TextAlign = HorizontalAlignment.Center
        .Width = 142
    End With
    Me.ListView1.Columns.Add(columnHeader1)
    Me.ListView1.Columns.Add(columnHeader2)

    Dim count As Integer

    For count = 0 To menuItems.Length - 1
        Dim listItem As New ListViewItem(menuItems(count))
        listItem.SubItems.Add(menuPrices(count))
        ListView1.Items.Add(listItem)
    Next

    ' Use the Selected property to select the first item on 
    ' the list.
    ListView1.Focus()
    ListView1.Items(0).Selected = True
End Sub


Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click

    ' Create new values for the ListView, clear the list, 
    ' and repopulate it.
    Dim lunch() As String = New String() {"Hamburger", _ 
        "Grilled Cheese", "Soup & Salad", "Club Sandwich", "Hotdog"}

    Dim lunchPrices() As String = New String() {"4.09", "5.09", _
        "5.19", "4.79", "2.09"}

    ListView1.Clear()

    PopulateMenu("Lunch", lunch, lunchPrices)
    Button1.Enabled = False
End Sub

Commenti

È possibile usare questo metodo per rimuovere tutti gli elementi e le colonne dal ListView controllo senza dover chiamare i singoli Clear metodi dalle ListView.ColumnHeaderCollection classi e ListView.ListViewItemCollection .

Nota

Il Clear metodo non è chiaro Groups specificato per il ListView controllo. Per cancellare Groups la chiamata ListViewGroupCollection.Clear.

Vedi anche

• Clear()
• Clear()