DrawListViewColumnHeaderEventArgs Class
Provides data for the ListView.DrawColumnHeader event.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
The ListView.DrawColumnHeader event lets you customize (or owner-draw) the appearance of a ListView control in the details view.
The ListView.DrawColumnHeader event is raised by a ListView control when its ListView.OwnerDraw property is set to true and its View property is set to Details. The DrawListViewColumnHeaderEventArgs passed to the event handler contains information about the ColumnHeader to draw and also provides methods to help you draw the header.
Use the Header property to retrieve information about the column header to draw. Use the Graphics property to do the actual drawing within the area specified by the Bounds property. To draw standard ListView elements that do not need customization, use the DrawBackground and DrawText methods.
Use the DrawDefault property when you want the operating system to draw the subitem. This is useful when you want to customize only specific headers.
Note: |
|---|
To avoid issues with graphics flickering when owner drawing, override the ListView control and set the DoubleBuffered property to true. This feature is available only on Windows XP and the Windows Server 2003 family when your application calls the Application.EnableVisualStyles method. |
The following code example demonstrates how to provide custom drawing for a ListView control. The ListView control in the example has a gradient background. Subitems with negative values have a red foreground and a black background.
A handler for the ListView.DrawItem event draws the background for entire items. A handler for the ListView.DrawSubItem event draws the text values and both the text and background for subitems that have negative values. A handler for the DrawColumnHeader event draws each column header.
A ContextMenu component provides a way to switch between the details view and the list view. In the list view, only the ListView.DrawItem event is fired. In this case, the text and background are both drawn in the ListView.DrawItem event handler.
Imports System Imports System.Drawing Imports System.Drawing.Drawing2D Imports System.Globalization Imports System.Windows.Forms Public Class ListViewOwnerDraw Inherits Form Private WithEvents listView1 As New ListView() Private WithEvents contextMenu1 As New ContextMenu() Private WithEvents listMenuItem As New MenuItem("List") Private WithEvents detailsMenuItem As New MenuItem("Details") Public Sub New() ' Initialize the shortcut menu. contextMenu1.MenuItems.AddRange(New MenuItem() _ {Me.listMenuItem, Me.detailsMenuItem}) ' Initialize the ListView control. With Me.listView1 .BackColor = Color.Black .ForeColor = Color.White .Dock = DockStyle.Fill .View = View.Details .FullRowSelect = True .OwnerDraw = True .ContextMenu = Me.contextMenu1 End With ' Add columns to the ListView control. With Me.listView1.Columns .Add("Name", 100, HorizontalAlignment.Center) .Add("First", 100, HorizontalAlignment.Center) .Add("Second", 100, HorizontalAlignment.Center) .Add("Third", 100, HorizontalAlignment.Center) End With ' Create items and add them to the ListView control. Dim listViewItem1 As New ListViewItem(New String() _ {"One", "20", "30", "-40"}, -1) Dim listViewItem2 As New ListViewItem(New String() _ {"Two", "-250", "145", "37"}, -1) Dim listViewItem3 As New ListViewItem(New String() _ {"Three", "200", "800", "-1,001"}, -1) Dim listViewItem4 As New ListViewItem(New String() _ {"Four", "not available", "-2", "100"}, -1) Me.listView1.Items.AddRange(New ListViewItem() _ {listViewItem1, listViewItem2, listViewItem3, listViewItem4}) ' Initialize the form and add the ListView control to it. With Me .ClientSize = New Size(450, 150) .FormBorderStyle = FormBorderStyle.FixedSingle .MaximizeBox = False .Text = "ListView OwnerDraw Example" .Controls.Add(Me.listView1) End With End Sub ' Clean up any resources being used. Protected Overrides Sub Dispose(ByVal disposing As Boolean) If disposing Then contextMenu1.Dispose() End If MyBase.Dispose(disposing) End Sub <STAThread()> _ Shared Sub Main() Application.Run(New ListViewOwnerDraw()) End Sub ' Sets the ListView control to the List view. Private Sub menuItemList_Click(ByVal sender As Object, _ ByVal e As EventArgs) _ Handles listMenuItem.Click Me.listView1.View = View.List End Sub ' Sets the ListView control to the Details view. Private Sub menuItemDetails_Click(ByVal sender As Object, _ ByVal e As EventArgs) _ Handles detailsMenuItem.Click Me.listView1.View = View.Details ' Reset the tag on each item to re-enable the workaround ' in the MouseMove event handler. For Each item As ListViewItem In listView1.Items item.Tag = Nothing Next End Sub ' Selects and focuses an item when it is clicked anywhere along ' its width. The click must normally be on the parent item text. Private Sub listView1_MouseUp(ByVal sender As Object, _ ByVal e As MouseEventArgs) _ Handles listView1.MouseUp Dim clickedItem As ListViewItem = Me.listView1.GetItemAt(5, e.Y) If (clickedItem IsNot Nothing) Then clickedItem.Selected = True clickedItem.Focused = True End If End Sub ' Draws the backgrounds for entire ListView items. Private Sub listView1_DrawItem(ByVal sender As Object, _ ByVal e As DrawListViewItemEventArgs) _ Handles listView1.DrawItem If Not (e.State And ListViewItemStates.Selected) = 0 Then ' Draw the background for a selected item. e.Graphics.FillRectangle(Brushes.Maroon, e.Bounds) e.DrawFocusRectangle() Else ' Draw the background for an unselected item. Dim brush As New LinearGradientBrush(e.Bounds, Color.Orange, _ Color.Maroon, LinearGradientMode.Horizontal) Try e.Graphics.FillRectangle(brush, e.Bounds) Finally brush.Dispose() End Try End If ' Draw the item text for views other than the Details view. If Not Me.listView1.View = View.Details Then e.DrawText() End If End Sub ' Draws subitem text and applies content-based formatting. Private Sub listView1_DrawSubItem(ByVal sender As Object, _ ByVal e As DrawListViewSubItemEventArgs) _ Handles listView1.DrawSubItem Dim flags As TextFormatFlags = TextFormatFlags.Left Dim sf As New StringFormat() Try ' Store the column text alignment, letting it default ' to Left if it has not been set to Center or Right. Select Case e.Header.TextAlign Case HorizontalAlignment.Center sf.Alignment = StringAlignment.Center flags = TextFormatFlags.HorizontalCenter Case HorizontalAlignment.Right sf.Alignment = StringAlignment.Far flags = TextFormatFlags.Right End Select ' Draw the text and background for a subitem with a ' negative value. Dim subItemValue As Double If e.ColumnIndex > 0 AndAlso _ Double.TryParse(e.SubItem.Text, NumberStyles.Currency, _ NumberFormatInfo.CurrentInfo, subItemValue) AndAlso _ subItemValue < 0 Then ' Unless the item is selected, draw the standard ' background to make it stand out from the gradient. If (e.ItemState And ListViewItemStates.Selected) = 0 Then e.DrawBackground() End If ' Draw the subitem text in red to highlight it. e.Graphics.DrawString(e.SubItem.Text, _ Me.listView1.Font, Brushes.Red, e.Bounds, sf) Return End If ' Draw normal text for a subitem with a nonnegative ' or nonnumerical value. e.DrawText(flags) Finally sf.Dispose() End Try End Sub ' Draws column headers. Private Sub listView1_DrawColumnHeader(ByVal sender As Object, _ ByVal e As DrawListViewColumnHeaderEventArgs) _ Handles listView1.DrawColumnHeader Dim sf As New StringFormat() Try ' Store the column text alignment, letting it default ' to Left if it has not been set to Center or Right. Select Case e.Header.TextAlign Case HorizontalAlignment.Center sf.Alignment = StringAlignment.Center Case HorizontalAlignment.Right sf.Alignment = StringAlignment.Far End Select ' Draw the standard header background. e.DrawBackground() ' Draw the header text. Dim headerFont As New Font("Helvetica", 10, FontStyle.Bold) Try e.Graphics.DrawString(e.Header.Text, headerFont, _ Brushes.Black, e.Bounds, sf) Finally headerFont.Dispose() End Try Finally sf.Dispose() End Try End Sub ' Forces each row to repaint itself the first time the mouse moves over ' it, compensating for an extra DrawItem event sent by the wrapped ' Win32 control. Private Sub listView1_MouseMove(ByVal sender As Object, _ ByVal e As MouseEventArgs) _ Handles listView1.MouseMove Dim item As ListViewItem = listView1.GetItemAt(e.X, e.Y) If item IsNot Nothing AndAlso item.Tag Is Nothing Then listView1.Invalidate(item.Bounds) item.Tag = "tagged" End If End Sub ' Resets the item tags. Private Sub listView1_Invalidated(ByVal sender As Object, _ ByVal e As InvalidateEventArgs) Handles listView1.Invalidated For Each item As ListViewItem In listView1.Items If item Is Nothing Then Return item.Tag = Nothing Next End Sub ' Forces the entire control to repaint if a column width is changed. Private Sub listView1_ColumnWidthChanged(ByVal sender As Object, _ ByVal e As ColumnWidthChangedEventArgs) Handles listView1.ColumnWidthChanged listView1.Invalidate() End Sub End Class
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Note: