ListView.BeginUpdate Metode

Definisi

Ruang nama:

System.Windows.Forms

Rakitan:

System.Windows.Forms.dll

Sumber:

ListView.cs

Mencegah kontrol menggambar hingga metode dipanggil EndUpdate() .

public:
 void BeginUpdate();

public void BeginUpdate();

member this.BeginUpdate : unit -> unit

Public Sub BeginUpdate ()

Contoh

Contoh kode berikut menunjukkan inisialisasi ListView kontrol untuk berisi kotak centang. Ini juga menunjukkan cara menggunakan BeginUpdate metode dan EndUpdate . Untuk menjalankan contoh ini, tempelkan kode berikut ke dalam formulir yang berisi bernama ListViewListView1. InitializeListView Panggil metode dari konstruktor atau Load metode formulir.

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

Keterangan

Cara yang disukai untuk menambahkan beberapa item ke adalah ListView dengan menggunakan AddRange metode ListView.ListViewItemCollection (diakses melalui Items properti ListView). Ini memungkinkan Anda menambahkan array item ke daftar dalam satu operasi. Namun, jika Anda ingin menambahkan item satu per satu menggunakan Add metode ListView.ListViewItemCollection kelas , Anda dapat menggunakan BeginUpdate metode untuk mencegah kontrol mengecat ListView ulang setiap kali item ditambahkan. Ketika Anda telah menyelesaikan tugas menambahkan item ke kontrol, panggil EndUpdate metode untuk mengaktifkan ListView pengecatan ulang. Cara menambahkan item ini dapat mencegah gambar ListView berkedot ketika banyak item ditambahkan ke kontrol.

Jika BeginUpdate dipanggil lebih dari sekali, EndUpdate harus disebut jumlah yang setara. Sampai panggilan terakhir ke EndUpdateListView tidak akan dicat ulang. Selain itu, beberapa panggilan BeginUpdate tidak berpengaruh.

Lihat juga

• EndUpdate()
• AddRange(ListViewItem[])
• Add(String)