ItemCheckEventArgs Class

 

Provides data for the ItemCheck event of the CheckedListBox and ListView controls.

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

System.Object
  System.EventArgs
    System.Windows.Forms.ItemCheckEventArgs

<ComVisibleAttribute(True)>
Public Class ItemCheckEventArgs
	Inherits EventArgs

NameDescription
System_CAPS_pubmethodItemCheckEventArgs(Int32, CheckState, CheckState)

Initializes a new instance of the ItemCheckEventArgs class.

NameDescription
System_CAPS_pubpropertyCurrentValue

Gets a value indicating the current state of the item's check box.

System_CAPS_pubpropertyIndex

Gets the zero-based index of the item to change.

System_CAPS_pubpropertyNewValue

Gets or sets a value indicating whether to set the check box for the item to be checked, unchecked, or indeterminate.

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

The ItemCheck event occurs when the checked state of an item in a checked list box changes. The ItemCheckEventArgs class specifies the index of the item to change, the current value of the check box for the item, and the new value to set for the check box.

For more information about handling events, see Handling and Raising Events.

The following code example demonstrates a checked ListView control that handles the ListView.ItemCheck event. The method uses the CurrentValue and Index properties of the ItemCheckEventArgs object to retrieve and tally the price of the menu items selected. To run this example paste the following code in 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 all events are associated with their event-handling methods.

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
Dim price As Double = 0.0

' Handles the ItemChecked event. The method uses the CurrentValue property 
' of the ItemCheckEventArgs to retrieve and tally the price of the menu 
' items selected.  
Private Sub ListView1_ItemCheck1(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.ItemCheckEventArgs) _
    Handles ListView1.ItemCheck

    If (e.CurrentValue = CheckState.Unchecked) Then
        price += Double.Parse( _
        Me.ListView1.Items(e.Index).SubItems(1).Text)
    ElseIf (e.CurrentValue = CheckState.Checked) Then
        price -= Double.Parse( _
            Me.ListView1.Items(e.Index).SubItems(1).Text)
    End If

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

End Sub

.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Return to top
Show: