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ListView.ItemCheck Event

Occurs when the check state of an item changes.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

public event ItemCheckEventHandler ItemCheck
/** @event */
public void add_ItemCheck (ItemCheckEventHandler value)

/** @event */
public void remove_ItemCheck (ItemCheckEventHandler value)

JScript supports the use of events, but not the declaration of new ones.

The CheckBoxes property must be set to true in order for check boxes to be displayed next to each item in the ListView control. The ItemCheck event occurs when the check state of an item changes or when the CheckBoxes property is set to true. You can create an event handler for the ItemCheck event to perform tasks such as changing the state of an item's icon or another application-specific task each time an item is checked in the ListView control.

NoteNote

If the Visible property of the ListView control is set to false at the time the control is created, the ItemCheck event is not raised. Once the control is visible, the event is raised regardless of the state of the Visible property.

For more information about handling events, see Consuming Events.

The following code example demonstrates a checked ListView control that handles the ItemCheck event. The method uses the ItemCheckEventArgs.CurrentValue and ItemCheckEventArgs.Index properties to retrieve and tally the price of the menu items selected. To run this example, paste the following code into a form containing a ListView named ListView1 and a TextBox named Textbox1. Call the InititalizeListView method from the form's constructor or Load method. Ensure that the ItemCheck event is associated with the event handler in this example.

	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);
	}
...	double price = 0.0;

	// Handles the ItemCheck event. The method uses the CurrentValue
	// property of the ItemCheckEventArgs to retrieve and tally the  
	// price of the menu items selected.  
	private void ListView1_ItemCheck1(object sender, 
		System.Windows.Forms.ItemCheckEventArgs e)
	{
		if (e.CurrentValue==CheckState.Unchecked)
		{
			price += Double.Parse(
				this.ListView1.Items[e.Index].SubItems[1].Text);
		}
		else if((e.CurrentValue==CheckState.Checked))
		{
			price -= Double.Parse(
				this.ListView1.Items[e.Index].SubItems[1].Text);
		}

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

    private void InitializeListView()
    {
        this.listView1 = new System.Windows.Forms.ListView();
        // Set properties such as BackColor and DockStyle and Location.
        this.listView1.set_BackColor(System.Drawing.SystemColors.get_Control());
        this.listView1.set_Dock(System.Windows.Forms.DockStyle.Top);
        this.listView1.set_Location(new System.Drawing.Point(0, 0));
        this.listView1.set_Size(new System.Drawing.Size(292, 130));
        this.listView1.set_View(System.Windows.Forms.View.Details);
        this.listView1.set_HideSelection(false);
        // Allow the user to select multiple items.
        this.listView1.set_MultiSelect(true);
        // Show CheckBoxes in the ListView.
        this.listView1.set_CheckBoxes(true);
        //Set the column headers and populate the columns.
        listView1.set_HeaderStyle(ColumnHeaderStyle.Nonclickable);

        ColumnHeader columnHeader1 = new ColumnHeader();
        columnHeader1.set_Text("Breakfast Choices");
        columnHeader1.set_TextAlign(HorizontalAlignment.Left);
        columnHeader1.set_Width(146);

        ColumnHeader columnHeader2 = new ColumnHeader();
        columnHeader2.set_Text("Price Each");
        columnHeader2.set_TextAlign(HorizontalAlignment.Center);
        columnHeader2.set_Width(142);

        this.listView1.get_Columns().Add(columnHeader1);
        this.listView1.get_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((String)foodList.get_Item(count));
            listItem.get_SubItems().Add((String)foodPrice.get_Item(count));
            listView1.get_Items().Add(listItem);
        }
        //Call EndUpdate when you finish adding items to the ListView.
        listView1.EndUpdate();
        this.get_Controls().Add(this.listView1);
    } //InitializeListView
...    private double price = 0.0;

    // Handles the ItemCheck event. The method uses the CurrentValue
    // property of the ItemCheckEventArgs to retrieve and tally the  
    // price of the menu items selected.  
    private void listView1_ItemCheck1(Object sender,
        System.Windows.Forms.ItemCheckEventArgs e)
    {
        if (e.get_CurrentValue().Equals(CheckState.Unchecked)) {
            price += System.Double.Parse(
                this.listView1.get_Items().get_Item(e.get_Index()).
                get_SubItems().get_Item(1).get_Text());
        }
        else {
            if (e.get_CurrentValue().Equals(CheckState.Checked)) {
                price -= System.Double.Parse(this.listView1.get_Items().
                    get_Item(e.get_Index()).get_SubItems().get_Item(1).
                    get_Text());
            }
        }
        // Output the price to TextBox1.
        textBox1.set_Text(((System.Double)price).ToString());
    } //listView1_ItemCheck1

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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