ListView.BeginUpdate ListView.BeginUpdate ListView.BeginUpdate ListView.BeginUpdate Method

Définition

Empêche le contrôle de redessiner tant que la méthode EndUpdate() n'est pas appelée.Prevents the control from drawing until the EndUpdate() method is called.

public:
 void BeginUpdate();
public void BeginUpdate ();
member this.BeginUpdate : unit -> unit
Public Sub BeginUpdate ()

Exemples

L’exemple de code suivant montre comment initialiser un ListView contrôle pour contenir des cases à cocher.The following code example demonstrates initializing a ListView control to contain check boxes. Il montre également comment utiliser les BeginUpdate méthodes et. EndUpdateIt also demonstrates how to use the BeginUpdate and EndUpdate methods. Pour exécuter cet exemple, collez le code suivant dans un formulaire qui contient ListView un ListView1nommé.To run this example, paste the following code into a form that contains a ListView named ListView1. Appelez la InitializeListView méthode à partir du constructeur ou Load de la méthode du formulaire.Call the InitializeListView method from the form's constructor or Load method.

void InitializeListView()
{
   this->ListView1 = gcnew System::Windows::Forms::ListView;
   
   // Set properties such as BackColor and DockStyle and Location.
   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->Size = System::Drawing::Size( 292, 130 );
   this->ListView1->View = System::Windows::Forms::View::Details;
   this->ListView1->HideSelection = false;
   
   // Allow the user to select multiple items.
   this->ListView1->MultiSelect = true;
   
   // Show CheckBoxes in the ListView.
   this->ListView1->CheckBoxes = true;
   
   //Set the column headers and populate the columns.
   ListView1->HeaderStyle = ColumnHeaderStyle::Nonclickable;
   ColumnHeader^ columnHeader1 = gcnew ColumnHeader;
   columnHeader1->Text = "Breakfast Choices";
   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","2.79","2.09","2.69"};
   int count;
   
   // Members are added one at a time, so call BeginUpdate to ensure 
   // the list is painted only once, rather than as each list item is added.
   ListView1->BeginUpdate();
   for ( count = 0; count < foodList->Length; count++ )
   {
      ListViewItem^ listItem = gcnew ListViewItem( foodList[ count ] );
      listItem->SubItems->Add( foodPrice[ count ] );
      ListView1->Items->Add( listItem );
   }
   
   //Call EndUpdate when you finish adding items to the ListView.
   ListView1->EndUpdate();
   this->Controls->Add( this->ListView1 );
}
private void InitializeListView()
{
	this.ListView1 = new System.Windows.Forms.ListView();

	// Set properties such as BackColor and DockStyle and Location.
	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.Size = new System.Drawing.Size(292, 130);
	this.ListView1.View = System.Windows.Forms.View.Details;
	this.ListView1.HideSelection = false;

	// Allow the user to select multiple items.
	this.ListView1.MultiSelect = true;

	// Show CheckBoxes in the ListView.
	this.ListView1.CheckBoxes = true;
	
	//Set the column headers and populate the columns.
	ListView1.HeaderStyle = ColumnHeaderStyle.Nonclickable;
	
	ColumnHeader columnHeader1 = new ColumnHeader();
	columnHeader1.Text = "Breakfast Choices";
	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", 
		"2.79", "2.09", "2.69"};
	
	int count;

	// Members are added one at a time, so call BeginUpdate to ensure 
	// the list is painted only once, rather than as each list item is added.
	ListView1.BeginUpdate();

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

	//Call EndUpdate when you finish adding items to the ListView.
	ListView1.EndUpdate();
	this.Controls.Add(this.ListView1);
}
Private Sub InitializeListView()
    Me.ListView1 = New System.Windows.Forms.ListView

    ' Set properties such as BackColor, Location and Size
    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.Size = New System.Drawing.Size(292, 130)
    Me.ListView1.View = System.Windows.Forms.View.Details
    Me.ListView1.HideSelection = False

    ' Allow user to select multiple items.
    Me.ListView1.MultiSelect = True

    ' Show check boxes in the ListView.
    Me.ListView1.CheckBoxes = True

    'Set the column headers and populate the columns.
    ListView1.HeaderStyle = ColumnHeaderStyle.Nonclickable
    Dim columnHeader1 As New ColumnHeader
    With columnHeader1
        .Text = "Breakfast Choices"
        .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", _
        "2.79", "2.09", "2.69"}
    Dim count As Integer

    ' Members are added one at a time, so call BeginUpdate to ensure 
    ' the list is painted only once, rather than as each list item is added.
    ListView1.BeginUpdate()

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

    'Call EndUpdate when you finish adding items to the ListView.
    ListView1.EndUpdate()
    Me.Controls.Add(Me.ListView1)
End Sub

Remarques

La meilleure façon d’ajouter plusieurs éléments à un ListView consiste à utiliser la AddRange méthode de l ListView.ListViewItemCollection ' (accessible via Items la propriété de ListViewl').The preferred way to add multiple items to a ListView is to use the AddRange method of the ListView.ListViewItemCollection (accessed through the Items property of the ListView). Cela vous permet d’ajouter un tableau d’éléments à la liste en une seule opération.This enables you to add an array of items to the list in a single operation. Toutefois, si vous souhaitez ajouter des éléments un par un à l’aide Add de la méthode ListView.ListViewItemCollection de la classe, vous pouvez BeginUpdate utiliser la méthode ListView pour empêcher le contrôle de repeindre à chaque fois qu’un élément est ajouté.However, if you want to add items one at a time using the Add method of the ListView.ListViewItemCollection class, you can use the BeginUpdate method to prevent the control from repainting the ListView every time that an item is added. Lorsque vous avez terminé la tâche d’ajout d’éléments au contrôle, appelez la EndUpdate méthode pour ListView permettre au de repeindre.When you have completed the task of adding items to the control, call the EndUpdate method to enable the ListView to repaint. Cette méthode d’ajout d’éléments peut empêcher le ListView dessin flickered du lorsqu’un grand nombre d’éléments est ajouté au contrôle.This way of adding items can prevent flickered drawing of the ListView when lots of items are being added to the control.

Si BeginUpdate est appelé plusieurs fois, EndUpdate doit être appelé un nombre équivalent de fois.If BeginUpdate is called more than once, EndUpdate must be called an equivalent number of times. Jusqu’à ce que le EndUpdate dernier ListView appel à ne redessine pas.Until the last call to EndUpdate the ListView will not repaint. À part cela, les appels multiples BeginUpdate à n’ont aucun effet.Other than this, multiple calls to BeginUpdate have no effect.

S’applique à

Voir aussi