DrawListViewColumnHeaderEventArgs Class
Definition
Important
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Provides data for the DrawColumnHeader event.
public ref class DrawListViewColumnHeaderEventArgs : EventArgspublic class DrawListViewColumnHeaderEventArgs : EventArgstype DrawListViewColumnHeaderEventArgs = class
inherit EventArgsPublic Class DrawListViewColumnHeaderEventArgs
Inherits EventArgs- Inheritance
Examples
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.
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Globalization;
using System.Windows.Forms;
public class ListViewOwnerDraw : Form
{
private ListView listView1 = new ListView();
private ContextMenu contextMenu1 = new ContextMenu();
public ListViewOwnerDraw()
{
// Initialize the ListView control.
listView1.BackColor = Color.Black;
listView1.ForeColor = Color.White;
listView1.Dock = DockStyle.Fill;
listView1.View = View.Details;
listView1.FullRowSelect = true;
// Add columns to the ListView control.
listView1.Columns.Add("Name", 100, HorizontalAlignment.Center);
listView1.Columns.Add("First", 100, HorizontalAlignment.Center);
listView1.Columns.Add("Second", 100, HorizontalAlignment.Center);
listView1.Columns.Add("Third", 100, HorizontalAlignment.Center);
// Create items and add them to the ListView control.
ListViewItem listViewItem1 = new ListViewItem(new string[] { "One", "20", "30", "-40" }, -1);
ListViewItem listViewItem2 = new ListViewItem(new string[] { "Two", "-250", "145", "37" }, -1);
ListViewItem listViewItem3 = new ListViewItem(new string[] { "Three", "200", "800", "-1,001" }, -1);
ListViewItem listViewItem4 = new ListViewItem(new string[] { "Four", "not available", "-2", "100" }, -1);
listView1.Items.AddRange(new ListViewItem[] { listViewItem1, listViewItem2, listViewItem3, listViewItem4 });
// Initialize the shortcut menu and
// assign it to the ListView control.
contextMenu1.MenuItems.Add("List",
new EventHandler(menuItemList_Click));
contextMenu1.MenuItems.Add("Details",
new EventHandler(menuItemDetails_Click));
listView1.ContextMenu = contextMenu1;
// Configure the ListView control for owner-draw and add
// handlers for the owner-draw events.
listView1.OwnerDraw = true;
listView1.DrawItem += new
DrawListViewItemEventHandler(listView1_DrawItem);
listView1.DrawSubItem += new
DrawListViewSubItemEventHandler(listView1_DrawSubItem);
listView1.DrawColumnHeader += new
DrawListViewColumnHeaderEventHandler(listView1_DrawColumnHeader);
// Add a handler for the MouseUp event so an item can be
// selected by clicking anywhere along its width.
listView1.MouseUp += new MouseEventHandler(listView1_MouseUp);
// Add handlers for various events to compensate for an
// extra DrawItem event that occurs the first time the mouse
// moves over each row.
listView1.MouseMove += new MouseEventHandler(listView1_MouseMove);
listView1.ColumnWidthChanged += new ColumnWidthChangedEventHandler(listView1_ColumnWidthChanged);
listView1.Invalidated += new InvalidateEventHandler(listView1_Invalidated);
// Initialize the form and add the ListView control to it.
this.ClientSize = new Size(450, 150);
this.FormBorderStyle = FormBorderStyle.FixedSingle;
this.MaximizeBox = false;
this.Text = "ListView OwnerDraw Example";
this.Controls.Add(listView1);
}
// Clean up any resources being used.
protected override void Dispose(bool disposing)
{
if (disposing)
{
contextMenu1.Dispose();
}
base.Dispose(disposing);
}
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new ListViewOwnerDraw());
}
// Sets the ListView control to the List view.
private void menuItemList_Click(object sender, EventArgs e)
{
listView1.View = View.List;
listView1.Invalidate();
}
// Sets the ListView control to the Details view.
private void menuItemDetails_Click(object sender, EventArgs e)
{
listView1.View = View.Details;
// Reset the tag on each item to re-enable the workaround in
// the MouseMove event handler.
foreach (ListViewItem item in listView1.Items)
{
item.Tag = null;
}
}
// Selects and focuses an item when it is clicked anywhere along
// its width. The click must normally be on the parent item text.
private void listView1_MouseUp(object sender, MouseEventArgs e)
{
ListViewItem clickedItem = listView1.GetItemAt(5, e.Y);
if (clickedItem != null)
{
clickedItem.Selected = true;
clickedItem.Focused = true;
}
}
// Draws the backgrounds for entire ListView items.
private void listView1_DrawItem(object sender,
DrawListViewItemEventArgs e)
{
if ((e.State & ListViewItemStates.Selected) != 0)
{
// Draw the background and focus rectangle for a selected item.
e.Graphics.FillRectangle(Brushes.Maroon, e.Bounds);
e.DrawFocusRectangle();
}
else
{
// Draw the background for an unselected item.
using (LinearGradientBrush brush =
new LinearGradientBrush(e.Bounds, Color.Orange,
Color.Maroon, LinearGradientMode.Horizontal))
{
e.Graphics.FillRectangle(brush, e.Bounds);
}
}
// Draw the item text for views other than the Details view.
if (listView1.View != View.Details)
{
e.DrawText();
}
}
// Draws subitem text and applies content-based formatting.
private void listView1_DrawSubItem(object sender,
DrawListViewSubItemEventArgs e)
{
TextFormatFlags flags = TextFormatFlags.Left;
using (StringFormat sf = new StringFormat())
{
// Store the column text alignment, letting it default
// to Left if it has not been set to Center or Right.
switch (e.Header.TextAlign)
{
case HorizontalAlignment.Center:
sf.Alignment = StringAlignment.Center;
flags = TextFormatFlags.HorizontalCenter;
break;
case HorizontalAlignment.Right:
sf.Alignment = StringAlignment.Far;
flags = TextFormatFlags.Right;
break;
}
// Draw the text and background for a subitem with a
// negative value.
double subItemValue;
if (e.ColumnIndex > 0 && Double.TryParse(
e.SubItem.Text, NumberStyles.Currency,
NumberFormatInfo.CurrentInfo, out subItemValue) &&
subItemValue < 0)
{
// Unless the item is selected, draw the standard
// background to make it stand out from the gradient.
if ((e.ItemState & ListViewItemStates.Selected) == 0)
{
e.DrawBackground();
}
// Draw the subitem text in red to highlight it.
e.Graphics.DrawString(e.SubItem.Text,
listView1.Font, Brushes.Red, e.Bounds, sf);
return;
}
// Draw normal text for a subitem with a nonnegative
// or nonnumerical value.
e.DrawText(flags);
}
}
// Draws column headers.
private void listView1_DrawColumnHeader(object sender,
DrawListViewColumnHeaderEventArgs e)
{
using (StringFormat sf = new StringFormat())
{
// Store the column text alignment, letting it default
// to Left if it has not been set to Center or Right.
switch (e.Header.TextAlign)
{
case HorizontalAlignment.Center:
sf.Alignment = StringAlignment.Center;
break;
case HorizontalAlignment.Right:
sf.Alignment = StringAlignment.Far;
break;
}
// Draw the standard header background.
e.DrawBackground();
// Draw the header text.
using (Font headerFont =
new Font("Helvetica", 10, FontStyle.Bold))
{
e.Graphics.DrawString(e.Header.Text, headerFont,
Brushes.Black, e.Bounds, sf);
}
}
return;
}
// 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. This issue occurs each time the ListView is invalidated.
private void listView1_MouseMove(object sender, MouseEventArgs e)
{
ListViewItem item = listView1.GetItemAt(e.X, e.Y);
if (item != null && item.Tag == null)
{
listView1.Invalidate(item.Bounds);
item.Tag = "tagged";
}
}
// Resets the item tags.
void listView1_Invalidated(object sender, InvalidateEventArgs e)
{
foreach (ListViewItem item in listView1.Items)
{
if (item == null) return;
item.Tag = null;
}
}
// Forces the entire control to repaint if a column width is changed.
void listView1_ColumnWidthChanged(object sender,
ColumnWidthChangedEventArgs e)
{
listView1.Invalidate();
}
}
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
Remarks
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.
Constructors
| DrawListViewColumnHeaderEventArgs(Graphics, Rectangle, Int32, ColumnHeader, ListViewItemStates, Color, Color, Font) |
Initializes a new instance of the DrawListViewColumnHeaderEventArgs class. |
Properties
| BackColor |
Gets the background color of the header. |
| Bounds |
Gets the size and location of the column header to draw. |
| ColumnIndex |
Gets the index of the ColumnHeader representing the header to draw. |
| DrawDefault |
Gets or sets a value indicating whether the column header should be drawn by the operating system instead of owner-drawn. |
| Font |
Gets the font used to draw the column header text. |
| ForeColor |
Gets the foreground color of the header. |
| Graphics |
Gets the Graphics used to draw the column header. |
| Header |
Gets the ColumnHeader representing the column header to draw. |
| State |
Gets the current state of the column header. |
Methods
| DrawBackground() |
Draws the background of the column header. |
| DrawText() |
Draws the column header text using the default formatting. |
| DrawText(TextFormatFlags) |
Draws the column header text, formatting it with the specified TextFormatFlags values. |
| Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
| GetHashCode() |
Serves as the default hash function. (Inherited from Object) |
| GetType() |
Gets the Type of the current instance. (Inherited from Object) |
| MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
| ToString() |
Returns a string that represents the current object. (Inherited from Object) |
Applies to
See also
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