Re: Owner drawn listbox
From: Kevin Aubuchon (kevin.aubuchon_at_sbcglobal.net)
Date: 08/06/04
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Date: Fri, 06 Aug 2004 02:19:06 GMT
Here is a class (OwnerDrawListBox) I wrote that puts items in a listbox with
the option of a bold font. Pass a reference of the listbox to the
OwnerDrawListBox object, and use the objects Add method for adding items to
the Listbox. Obviously the value of this example is how to implement
drawItem() and measureItem(). I think that's the cause of your problem.
Modify the class to implement your logic.
HTH,
kevin aubuchon
Imports System.Windows.Forms
Imports System.Drawing
Imports System.Drawing.Text
Public Class OwnerDrawListBox
'
' Kevin Aubuchon 5/6/2004
'
'
' Utility class to handle owner draw listboxes. Individual line items
' may be drawn with different fonts, colors, etc.
'
' Currently if a row is 'special', then the current font is
' used but made bold. Add implementation as needed for more
' exotic treatment (different background colors, etc.)
'
Private lb As ListBox
Private bBold As Boolean = True
Private boldFont As Font
'
' helper class to hold 'special' status
'
Class helper
Inherits Object
Dim txt As String
Friend special As Boolean
Sub New(ByVal s As String, ByVal sp As Boolean)
txt = s
special = sp
End Sub
Public Overrides Function ToString() As String
Return txt
End Function
End Class
Public Sub New(ByVal theListBox As ListBox)
If IsNothing(theListBox) Then Throw New
NullReferenceException("ListBox object empty")
lb = theListBox
boldFont = New System.Drawing.Font(lb.Parent.Font, FontStyle.Bold)
lb.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable
AddHandler lb.DrawItem, AddressOf drawItem
AddHandler lb.MeasureItem, AddressOf measureItem
End Sub
Public Property UseBoldFont() As Boolean
Get
Return bBold
End Get
Set(ByVal Value As Boolean)
bBold = Value
End Set
End Property
Public Sub Add(ByVal s As String, ByVal special As Boolean)
lb.Items.Add(New helper(s, special))
End Sub
Public Sub Clear()
lb.Items.Clear()
End Sub
Private Sub drawItem(ByVal sender As Object, ByVal e As
DrawItemEventArgs)
Dim brush As Brush
' The following method should generally be called before drawing.
' It is actually superfluous here, since the subsequent drawing
' will completely cover the area of interest.
e.DrawBackground()
If e.Index < 0 OrElse e.Index > Me.lb.Items.Count - 1 Then Exit Sub
'The system provides the context
'into which the owner custom-draws the required graphics.
'The context into which to draw is e.graphics.
'The index of the item to be painted is e.Index.
'The painting should be done into the area described by e.Bounds.
brush = Brushes.White
e.Graphics.FillRectangle(brush, e.Bounds)
Dim f As Font
Dim h As helper = CType(lb.Items.Item(e.Index), helper)
If Not IsNothing(h) AndAlso h.special Then
f = boldFont
Else
f = lb.Parent.Font
End If
e.Graphics.DrawString(h.ToString(), f, Brushes.Black, e.Bounds.X,
e.Bounds.Y)
End Sub
'Return the height of the item to be drawn
Private Sub measureItem(ByVal sender As Object, ByVal e As
MeasureItemEventArgs)
Dim displayText As String
Dim stringSize As SizeF
If e.Index < 0 OrElse e.Index > Me.lb.Items.Count - 1 Then Exit Sub
'Work out what the text will be
Dim h As helper = CType(lb.Items.Item(e.Index), helper)
displayText = h.ToString()
'Get width & height of string
stringSize = e.Graphics.MeasureString(displayText, lb.Parent.Font)
'Account for top margin
stringSize.Height += 3
e.ItemHeight = CInt(stringSize.Height)
End Sub
End Class
"Patty O'Dors" <PattyODors@discussions.microsoft.com> wrote in message
news:E76205AC-3633-478E-A0A3-BB20F3737CFA@microsoft.com...
> Hi
> I have some code to create an ownerdrawn listbox (derived), and when I add
> an item to it, the bold text of the first item (the title, 'Collections
and
> Maturities') mysteriously seems to get bunched up at the right, i.e.
squashed
> up! any idea why?
>
> The main bit of the code is as such
> // (in progressReporter.cs)
>
> protected struct LBRow //a row of the listbox, whether it be the title or
a
> table listing
> {
> public string Text;
> public int Rows;
> public bool IsTitle;
> public LBRow(string text, int rows, bool istitle)
> {
> Text = text;
> Rows = rows;
> IsTitle = istitle;
> }
> }
>
> public void AddReport(ProgressReport p)
> {
> Items.Add(new LBRow(p.JobName, 0, true));
> foreach(ProgressReport.ProgressReportItem pi in p.TablesCopied)
> Items.Add(new LBRow(pi.TableName, pi.Rows, false));
> }
>
> public struct ProgressReport
> {
> public string JobName;
> public ProgressReportItem[] TablesCopied;
> public struct ProgressReportItem
> {
> public string TableName;
> public int Rows;
> public ProgressReportItem(string tablename, int rows)
> {
> TableName = tablename;
> Rows = rows;
> }
> }
> public ProgressReport(string jobname, params ProgressReportItem[]
> tablescopied)
> {
> JobName = jobname;
> TablesCopied = tablescopied;
> }
> }
>
>
> // (in frmMain)
>
> private void Form1_Load(object sender, System.EventArgs e)
> {
> listBox2.AddReport(new ProgressReporter.ProgressReport(
> "Collections and Maturities",
> new ProgressReporter.ProgressReport.ProgressReportItem("Table1", 100000),
> new ProgressReporter.ProgressReport.ProgressReportItem("Table2",
500000)));
> }
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