ListView.SelectedIndexChanged Evento

  • Referência

Definição

Namespace:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll

Ocorre quando a coleção SelectedIndices é alterada.

public:
 event EventHandler ^ SelectedIndexChanged;
public event EventHandler SelectedIndexChanged;
public event EventHandler? SelectedIndexChanged;
member this.SelectedIndexChanged : EventHandler 
Public Custom Event SelectedIndexChanged As EventHandler

Tipo de evento

EventHandler

Exemplos

O exemplo de código a seguir demonstra como usar a propriedade, SelectedIndexChanged o SelectedItems evento, HeaderStyle os membros e a ListView.SelectedListViewItemCollection classe . Para executar este exemplo, cole o código a seguir em um formulário que contém um ListView objeto chamado ListView1 e um TextBox chamado TextBox1. Chame o InitializeListView método do construtor ou Load método do formulário. Este exemplo requer que o manipulador de eventos esteja corretamente associado ao SelectedIndexChanged evento

// This method adds two columns to the ListView, setting the Text 
// and TextAlign, and Width properties of each ColumnHeader.  The 
// HeaderStyle property is set to NonClickable since the ColumnClick 
// event is not handled.  Finally the method adds ListViewItems and 
// SubItems to each column.
void InitializeListView()
{
   this->ListView1 = gcnew System::Windows::Forms::ListView;
   this->ListView1->BackColor = System::Drawing::SystemColors::Control;
   this->ListView1->Dock = System::Windows::Forms::DockStyle::Top;
   this->ListView1->Location = System::Drawing::Point( 0, 0 );
   this->ListView1->Name = "ListView1";
   this->ListView1->Size = System::Drawing::Size( 292, 130 );
   this->ListView1->TabIndex = 0;
   this->ListView1->View = System::Windows::Forms::View::Details;
   this->ListView1->MultiSelect = true;
   this->ListView1->HideSelection = false;
   this->ListView1->HeaderStyle = ColumnHeaderStyle::Nonclickable;
   ColumnHeader^ columnHeader1 = gcnew ColumnHeader;
   columnHeader1->Text = "Breakfast Item";
   columnHeader1->TextAlign = HorizontalAlignment::Left;
   columnHeader1->Width = 146;
   ColumnHeader^ columnHeader2 = gcnew ColumnHeader;
   columnHeader2->Text = "Price Each";
   columnHeader2->TextAlign = HorizontalAlignment::Center;
   columnHeader2->Width = 142;
   this->ListView1->Columns->Add( columnHeader1 );
   this->ListView1->Columns->Add( columnHeader2 );
   array<String^>^foodList = {"Juice","Coffee","Cereal & Milk","Fruit Plate","Toast & Jelly","Bagel & Cream Cheese"};
   array<String^>^foodPrice = {"1.09","1.09","2.19","2.49","1.49","1.49"};
   for ( int count = 0; count < foodList->Length; count++ )
   {
      ListViewItem^ listItem = gcnew ListViewItem( foodList[ count ] );
      listItem->SubItems->Add( foodPrice[ count ] );
      ListView1->Items->Add( listItem );

   }
   this->Controls->Add( ListView1 );
}

  // This method adds two columns to the ListView, setting the Text 
  // and TextAlign, and Width properties of each ColumnHeader.  The 
  // HeaderStyle property is set to NonClickable since the ColumnClick 
  // event is not handled.  Finally the method adds ListViewItems and 
  // SubItems to each column.
  private void InitializeListView()
  {
      this.ListView1 = new System.Windows.Forms.ListView();
      this.ListView1.BackColor = System.Drawing.SystemColors.Control;
      this.ListView1.Dock = System.Windows.Forms.DockStyle.Top;
      this.ListView1.Location = new System.Drawing.Point(0, 0);
      this.ListView1.Name = "ListView1";
      this.ListView1.Size = new System.Drawing.Size(292, 130);
      this.ListView1.TabIndex = 0;
      this.ListView1.View = System.Windows.Forms.View.Details;
      this.ListView1.MultiSelect = true;
      this.ListView1.HideSelection = false;
      this.ListView1.HeaderStyle = ColumnHeaderStyle.Nonclickable;
      
      ColumnHeader columnHeader1 = new ColumnHeader();
      columnHeader1.Text = "Breakfast Item";
      columnHeader1.TextAlign = HorizontalAlignment.Left;
      columnHeader1.Width = 146;

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

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

      string[] foodList = new string[]{"Juice", "Coffee", 
          "Cereal & Milk", "Fruit Plate", "Toast & Jelly", 
          "Bagel & Cream Cheese"};
      string[] foodPrice = new string[]{"1.09", "1.09", "2.19", 
          "2.49", "1.49", "1.49"};
      
      for(int count=0; count < foodList.Length; count++)
      {
          ListViewItem listItem = new ListViewItem(foodList[count]);
          listItem.SubItems.Add(foodPrice[count]);
          ListView1.Items.Add(listItem);
      }
      this.Controls.Add(ListView1);
  }

' This method adds two columns to the ListView, setting the Text 
' and TextAlign, and Width properties of each ColumnHeader.  The 
' HeaderStyle property is set to NonClickable since the ColumnClick 
' event is not handled.  Finally the method adds ListViewItems and 
' SubItems to each column.
Private Sub InitializeListView()
    Me.ListView1 = New System.Windows.Forms.ListView
    Me.ListView1.BackColor = System.Drawing.SystemColors.Control
    Me.ListView1.Dock = System.Windows.Forms.DockStyle.Top
    Me.ListView1.Location = New System.Drawing.Point(0, 0)
    Me.ListView1.Name = "ListView1"
    Me.ListView1.Size = New System.Drawing.Size(292, 130)
    Me.ListView1.TabIndex = 0
    Me.ListView1.View = System.Windows.Forms.View.Details
    Me.ListView1.MultiSelect = True
    Me.ListView1.HideSelection = False
    ListView1.HeaderStyle = ColumnHeaderStyle.Nonclickable
    Dim columnHeader1 As New ColumnHeader
    With columnHeader1
        .Text = "Breakfast Item"
        .TextAlign = HorizontalAlignment.Left
        .Width = 146
    End With
    Dim columnHeader2 As New ColumnHeader
    With columnHeader2
        .Text = "Price Each"
        .TextAlign = HorizontalAlignment.Center
        .Width = 142
    End With

    Me.ListView1.Columns.Add(columnHeader1)
    Me.ListView1.Columns.Add(columnHeader2)
    Dim foodList() As String = New String() {"Juice", "Coffee", _
        "Cereal & Milk", "Fruit Plate", "Toast & Jelly", _
        "Bagel & Cream Cheese"}
    Dim foodPrice() As String = New String() {"1.09", "1.09", _
        "2.19", "2.49", "1.49", "1.49"}
    Dim count As Integer
    For count = 0 To foodList.Length - 1
        Dim listItem As New ListViewItem(foodList(count))
        listItem.SubItems.Add(foodPrice(count))
        ListView1.Items.Add(listItem)
    Next
    Me.Controls.Add(Me.ListView1)
End Sub

// Uses the SelectedItems property to retrieve and tally the price 
// of the selected menu items.
void ListView1_SelectedIndexChanged_UsingItems( Object^ /*sender*/, System::EventArgs^ /*e*/ )
{
   ListView::SelectedListViewItemCollection^ breakfast = this->ListView1->SelectedItems;
   double price = 0.0;
   System::Collections::IEnumerator^ myEnum = breakfast->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      ListViewItem^ item = safe_cast<ListViewItem^>(myEnum->Current);
      price += Double::Parse( item->SubItems[ 1 ]->Text );
   }

   // Output the price to TextBox1.
   TextBox1->Text = price.ToString();
}

// Uses the SelectedItems property to retrieve and tally the price 
// of the selected menu items.
private void ListView1_SelectedIndexChanged_UsingItems(
    object sender, System.EventArgs e)
{

    ListView.SelectedListViewItemCollection breakfast = 
        this.ListView1.SelectedItems;
    
    double price = 0.0;
    foreach ( ListViewItem item in breakfast )
    {
        price += Double.Parse(item.SubItems[1].Text);
    }

    // Output the price to TextBox1.
    TextBox1.Text = price.ToString();
}

' Uses the SelectedItems property to retrieve and tally the price 
' of the selected menu items.
Private Sub ListView1_SelectedIndexChanged_UsingItems _
    (ByVal sender As Object, ByVal e As System.EventArgs) _
    Handles ListView1.SelectedIndexChanged

    Dim breakfast As ListView.SelectedListViewItemCollection = _
        Me.ListView1.SelectedItems
    Dim item As ListViewItem
    Dim price As Double = 0.0
    For Each item In breakfast
        price += Double.Parse(item.SubItems(1).Text)
    Next

    ' Output the price to TextBox1.
    TextBox1.Text = CType(price, String)
End Sub

Comentários

A SelectedIndices coleção é alterada sempre que a Selected propriedade de um ListViewItem é alterada. A alteração da propriedade pode ocorrer programaticamente ou quando o usuário seleciona um item ou limpa a seleção de um item. Quando o usuário seleciona um item sem pressionar CTRL para executar uma seleção múltipla, o controle primeiro limpa a seleção anterior. Nesse caso, esse evento ocorre uma vez para cada item que foi selecionado anteriormente e uma vez para o item recém-selecionado.

Para determinar quais itens estão selecionados no ListView controle, use a SelectedItems propriedade para acessar o ListView.SelectedListViewItemCollection. Você pode criar um manipulador de eventos para esse evento para executar tarefas sempre que houver uma alteração nos itens selecionados no ListView controle.

Para obter mais informações sobre como lidar com eventos, consulte Manipulando e gerando eventos.

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