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ListView.BeginUpdate Method

Prevents the control from drawing until the EndUpdate method is called.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public void BeginUpdate()

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). This enables you to add an array of items to the list in a single operation. 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. When you have completed the task of adding items to the control, call the EndUpdate method to enable the ListView to repaint. This way of adding items can prevent flickered drawing of the ListView when lots of items are being added to the control.

If BeginUpdate is called more than once, EndUpdate must be called an equivalent number of times. Until the last call to EndUpdate the ListView will not repaint. Other than this, multiple calls to BeginUpdate have no effect.

The following code example demonstrates initializing a ListView control to contain check boxes. It also demonstrates how to use the BeginUpdate and EndUpdate methods. To run this example, paste the following code into a form that contains a ListView named ListView1. Call the InititalizeListView method from the form's constructor or Load method.


	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);
	}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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