DrawListViewSubItemEventArgs 類別

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

提供 DrawSubItem 事件的資料。

public ref class DrawListViewSubItemEventArgs : EventArgs

public class DrawListViewSubItemEventArgs : EventArgs

type DrawListViewSubItemEventArgs = class
    inherit EventArgs

Public Class DrawListViewSubItemEventArgs
Inherits EventArgs

繼承

Object

EventArgs

DrawListViewSubItemEventArgs

範例

下列程式碼範例示範如何為控制項提供自訂繪圖 ListView 。 範例 ListView 中的 控制項具有漸層背景。 負值的子專案具有紅色前景和黑色背景。

事件的處理常式 ListView.DrawItem 會繪製整個專案的背景。 事件的處理常式 ListView.DrawSubItem 會繪製文字值，以及具有負值的子專案的文字和背景。 事件的處理常式 DrawColumnHeader 會繪製每個資料行標頭。

ContextMenu元件提供在詳細資料檢視與清單檢視之間切換的方法。 在清單檢視中，只會 ListView.DrawItem 引發 事件。 在此情況下，會在事件處理常式中 ListView.DrawItem 繪製文字和背景。

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

備註

此 ListView.DrawSubItem 事件可讓您自訂 (或擁有者繪製，) 詳細資料檢視中的控制面板 ListView 。

當 ListView.DrawSubItem 控制項的 屬性設定 true 為 ，且其 View 屬性設定 Details 為 時 ListView.OwnerDraw ，事件會由 ListView 控制項引發。 DrawListViewSubItemEventArgs傳遞至事件處理常式的 包含要繪製的資訊 ListViewItem.ListViewSubItem ，也提供方法來協助您繪製子專案。

ItemState使用 或 Item 屬性，擷取子專案的父專案相關資訊來繪製。 若要擷 ListViewItem.ListViewSubItem 取本身，請使用 SubItem 屬性。 Header使用 屬性擷取 ColumnHeader ，代表顯示子專案之資料行的標頭。

Graphics使用 屬性，在 屬性所 Bounds 指定的區域內執行實際繪圖。 若要繪製不需要自訂的標準 ListView 元素，請使用 DrawBackground 、 DrawText 和 DrawFocusRectangle 方法。

DrawDefault當您想要作業系統繪製子專案時，請使用 屬性。 當您只想要自訂特定子專案時，這會很有用。

注意

若要避免在擁有者繪圖時閃爍圖形的問題，請覆寫 ListView 控制項，並將 屬性設定 DoubleBuffered 為 true 。 當您的應用程式呼叫 Application.EnableVisualStyles 方法時，此功能僅適用于 Windows XP 和 Windows Server 2003 系列。

建構函式

DrawListViewSubItemEventArgs(Graphics, Rectangle, ListViewItem, ListViewItem+ListViewSubItem, Int32, Int32, ColumnHeader, ListViewItemStates)

初始化 DrawListViewSubItemEventArgs 類別的新執行個體。

屬性

Bounds	取得所要繪製 ListViewItem.ListViewSubItem 的大小和位置。
ColumnIndex	取得要在其中顯示 ListView 之 ListViewItem.ListViewSubItem 資料行的索引。
DrawDefault	取得或設定值，指出是否應該以作業系統 (而不以主控描繪) 來描繪 ListViewItem.ListViewSubItem。
Graphics	取得用來繪製 Graphics 的 ListViewItem.ListViewSubItem。
Header	取得要在其中顯示 ListView 之 ListViewItem.ListViewSubItem 資料行的行首。
Item	取得要繪製之 ListViewItem 的父代 ListViewItem.ListViewSubItem。
ItemIndex	取得要繪製之 ListViewItem 的父代 ListViewItem.ListViewSubItem 的索引。
ItemState	取得要繪製之 ListViewItem 的父代 ListViewItem.ListViewSubItem 的目前狀態。
SubItem	取得要繪製的 ListViewItem.ListViewSubItem。

方法

DrawBackground()	使用 ListViewItem.ListViewSubItem 目前的背景色彩來繪製它的背景。
DrawFocusRectangle(Rectangle)	如果父代 ListViewItem.ListViewSubItem 具有焦點，則會繪製 ListViewItem 的焦點矩形 (Focus Rectangle)。
DrawText()	使用 ListViewItem.ListViewSubItem 目前的前景色彩來繪製它的文字。
DrawText(TextFormatFlags)	使用 ListViewItem.ListViewSubItem 目前的前景色彩繪製它的文字，並利用指定的 TextFormatFlags 值設定格式。
Equals(Object)	判斷指定的物件是否等於目前的物件。 (繼承來源 Object)
GetHashCode()	做為預設雜湊函式。 (繼承來源 Object)
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)

另請參閱

• ListView
• DrawSubItem
• OwnerDraw
• View
• ListViewItem.ListViewSubItem
• View