Custom listview header redraw problem

[LucasCain]

I've been trying to subclass a listview control that allows a user to set a color property for the header background and have it automatically resize the columns to display all the header text when empty but I keep ending up with numerous redraw problems. I either end up with a gap at the end of the control or the first two columns are messed up. I've tried invalidating it in lots of different places or forcing it to redraw but I've only had small amounts of success.

In certain circumstances, I can get it to display correctly if the total length of all the header text is greater than the length of the control and other times I've got it working if the total length of all the header text is less than the length of the control but never both.



A few times I thought id cracked it only to find it was constantly redrawing in an infinite loop. I've added a custom event so I can check when it's stuck in a loop.

Imports System.Drawing.Drawing2D


Public Class LVA

    Inherits ListView

    Private _HeaderBackColor As Color
    Private _HeaderFont As Font

    Public Sub New()
        Me.OwnerDraw = True
        Me.View = View.Details
        Me.FullRowSelect = True

        SetStyle(ControlStyles.OptimizedDoubleBuffer, True)
        _HeaderFont = New Font("Segoe UI", 9.75, FontStyle.Regular)
        _HeaderBackColor = Color.Gray
    End Sub

    ' Draws column headers.
    Private Sub LVA_DrawColumnHeader(ByVal sender As Object, ByVal e As DrawListViewColumnHeaderEventArgs) Handles Me.DrawColumnHeader

        infoout("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

            sf.LineAlignment = StringAlignment.Center

            ' Draw the standard header background.
            e.DrawBackground()

            ' Draw the header text.
            e.Graphics.FillRectangle(New SolidBrush(_HeaderBackColor), e.Bounds)
            e.Graphics.DrawString(e.Header.Text, _HeaderFont, New SolidBrush(Color.Gainsboro), e.Bounds, sf)

            'Add a spacer
            Dim newcolor As Color = Color.FromArgb(_HeaderBackColor.ToArgb() Xor &HFFFFFF)
            If e.ColumnIndex < Columns.Count - 1 Then
                e.Graphics.DrawLine(New Pen(Color.Black), e.Bounds.X, e.Bounds.Y + 2, e.Bounds.X, e.Bounds.Height - 2)
            End If

        Finally
            sf.Dispose()
        End Try

    End Sub


    Protected Overrides Sub OnDrawColumnHeader(e As DrawListViewColumnHeaderEventArgs)
        MyBase.OnDrawColumnHeader(e)
        'trying to force a redraw here
       If Columns(e.ColumnIndex).Width <> GetTextWidth(e.Header.Text, _HeaderFont) + 5 Then
            e.Header.AutoResize(ColumnHeaderAutoResizeStyle.HeaderSize)
        End If
    End Sub

    Private Function GetTextWidth(txt As String, fnt As Font) As integer
        Dim sI As SizeF

        Using g As Graphics = Graphics.FromHwnd(IntPtr.Zero)
            sI = g.MeasureString(txt, fnt)
        End Using

        Return CInt(sI.Width)
    End Function

    Public Event NewInfo(ByVal e As eInfo)

    Private Sub InfoOut(str As String)
        RaiseEvent NewInfo(New eInfo(str))
    End Sub

End Class


Public Class eInfo

    Inherits EventArgs

    Private _SomeInfo As String
    Public Property SomeInfo() As String
        Get
            Return _SomeInfo
        End Get
        Set(ByVal value As String)
            _SomeInfo = value
        End Set
    End Property

    Public Sub New( NewInfo As String)
        MyBase.New
        _SomeInfo = NewInfo
    End Sub

End Class

I've also tried adding several types of Auto resize methods with only partial success.

''' <summary>
    ''' Automatically resizes the columns to fit the column content or the column header text depending on which is the widest
    ''' </summary>
    Public Sub Auto_Column_Resize()
        Dim HeaderTextLength As Integer
        Dim cHeader As New ColumnHeader
        Dim LongestText As String

        For i = 0 To Columns.Count - 1
                cHeader = Columns(i)
                HeaderTextLength = cHeader.Text.Length
                LongestText = cHeader.Text
            For inc = 0 To Items.Count - 1

                If Items(inc).SubItems(i).Text.Length > HeaderTextLength Then
                    HeaderTextLength = Items(inc).SubItems(i).Text.Length
                    LongestText = Items(inc).SubItems(i).Text
                End If
            Next

            cHeader.Width = GetTextWidth(LongestText, Font) + 5
            Next

    End Sub

[ChrisE]

have you tried

.AutoResizeColumns(ColumnHeaderAutoResizeStyle.ColumnContent)

or

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        For Each col As ColumnHeader In ListView1.Columns
            col.Width = -2
        Next col
    End Sub

hth

[LucasCain]

Yes, that was some of the first stuff I tried.

.AutoResizeColumns(ColumnHeaderAutoResizeStyle.ColumnContent)

will only work if there are any items in the listview and what I'm after is to have it display the headers correctly when the listview has no items like when the listview is first displayed.

Ive also tried the second bit of code. I put it into the event as this gets called after the sub DrawColumnHeader has been run:

    Protected Overrides Sub OnDrawColumnHeader(e As DrawListViewColumnHeaderEventArgs)
        MyBase.OnDrawColumnHeader(e)
        'trying to force a redraw here

        If e.ColumnIndex = Columns.Count - 1 Then
            For Each col As ColumnHeader In Columns
                col.Width = -2
            Next col
        End If

    End Sub

If the total width of the header text is less than the length of the control I get:


and if its greater than the length of the control I get:

[ChrisE]

try this

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
      
        ListView1.BeginUpdate()
   
        Dim width As Integer = 1

        For Each col As ColumnHeader In ListView1.Columns
            width = col.Width

            ' column items greatest width
            col.Width = -1
            If width > col.Width Then
                col.Width = width
            End If

            ' column header width
            col.Width = -2
            If width > col.Width Then
                col.Width = width
            End If
        Next col

        ListView1.EndUpdate()

    End Sub

[Goggy]

Public Class ListViewEx
    Inherits System.Windows.Forms.ListView

    Public Sub New()
        Me.OwnerDraw = True

        Me.View = View.Details

    End Sub
    Protected Overrides Sub OnDrawColumnHeader(e As DrawListViewColumnHeaderEventArgs)

        Dim Text As String = $"Column nr:{e.ColumnIndex.ToString}"

        Me.Columns(e.ColumnIndex).Width = e.Graphics.MeasureString(Text.Replace(" ", "_"), Me.Font).Width


        With e.Graphics

            ControlPaint.DrawBorder3D(e.Graphics, e.Bounds, Border3DStyle.Sunken, Border3DSide.All)

            Using Br As New SolidBrush(Color.Black.ToOpaque(128))
                .FillRectangle(Br, e.Bounds)
            End Using

            .DrawString(Text, Me.Font, New SolidBrush(Color.Black), e.Bounds, New StringFormat With {.Alignment = StringAlignment.Center, .LineAlignment = StringAlignment.Center})
        End With


        MyBase.OnDrawColumnHeader(e)
    End Sub

End Class

Public Module ColorExtensions
    <Runtime.CompilerServices.Extension()>
    Public Function ToOpaque(C As Global.System.Drawing.Color, Opacity As Double) As Color
        Return Color.FromArgb(CInt(IIf(C.Equals(Color.Transparent), 0, Opacity)), C)
    End Function
End Module

[LucasCain]

try this

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
      
        ListView1.BeginUpdate()
   
        Dim width As Integer = 1

        For Each col As ColumnHeader In ListView1.Columns
            width = col.Width

            ' column items greatest width
            col.Width = -1
            If width > col.Width Then
                col.Width = width
            End If

            ' column header width
            col.Width = -2
            If width > col.Width Then
                col.Width = width
            End If
        Next col

        ListView1.EndUpdate()

    End Sub

Hi, thanks for the reply. There's a couple of problems with that bit of code, first it works off a button press where i want this to work automatically. Also where you have Width=col.width that just resizes the whole control. I changed the code to fit in the OnDrawColumnHeader event like this:

 Protected Overrides Sub OnDrawColumnHeader(e As DrawListViewColumnHeaderEventArgs)
        MyBase.OnDrawColumnHeader(e)
        'trying to force a redraw here

        BeginUpdate()

        If e.ColumnIndex = Columns.Count - 1 Then
            For Each col As ColumnHeader In Columns
                Dim nWidth As Integer = col.Width

                ' column items greatest width
                col.Width = -1
                If nWidth > col.Width Then
                    col.Width = nWidth
                End If

                ' column header width
                col.Width = -2
                If nWidth > col.Width Then
                    col.Width = Width
                End If
            Next col
        End If

        EndUpdate()
    End Sub

but it sends the control into an infinite loop.

[LucasCain]

Hi, thanks for the reply. That bit of code leaves a white gap at the end of the headers if the total width of the headers is less than the width of the control which I've been trying to avoid because the main reason I've been making this control is so that it fits in with darker themes. Also if the total width of the headers is greater than the width of the control it chops off any headers to the right.

[Goggy]

Second try:

Imports System.Linq

Public Class ListViewEx
    Inherits System.Windows.Forms.ListView

    Public Sub New()
        Me.OwnerDraw = True

        Me.View = View.Details

    End Sub
    Protected Overrides Sub OnDrawColumnHeader(e As DrawListViewColumnHeaderEventArgs)

        Dim Text As String = $"Column nr:{e.ColumnIndex.ToString}"
        Dim LeftOver As Double = Me.Width

        If e.ColumnIndex = Me.Columns.Count - 1 Then
            For index = 1 To Me.Columns.Count - 2
                LeftOver -= Me.Columns(index).Width
            Next
            Me.Columns(e.ColumnIndex).Width = LeftOver
        Else
            Me.Columns(e.ColumnIndex).Width = e.Graphics.MeasureString(Text.Replace(" ", "_"), Me.Font).Width
        End If

        With e.Graphics

            ControlPaint.DrawBorder3D(e.Graphics, e.Bounds, Border3DStyle.Sunken, Border3DSide.All)

            Using Br As New SolidBrush(Color.Black.ToOpaque(128))
                .FillRectangle(Br, e.Bounds)
            End Using

            .DrawString(Text, Me.Font, New SolidBrush(Color.Black), e.Bounds, New StringFormat With {.Alignment = StringAlignment.Center, .LineAlignment = StringAlignment.Center})
        End With


        MyBase.OnDrawColumnHeader(e)
    End Sub


End Class

Public Module ColorExtensions
    <Runtime.CompilerServices.Extension()>
    Public Function ToOpaque(C As Global.System.Drawing.Color, Opacity As Double) As Color
        Return Color.FromArgb(CInt(IIf(C.Equals(Color.Transparent), 0, Opacity)), C)
    End Function
End Module

[ChrisE]

goggy is on the right track

I changed hie idea... ....MeasureString
to ..TextRenderer.MeasureText...

 Private Function GetTextWidth(ByVal LiSub As ListViewItem.ListViewSubItem) As Integer

         Dim w As Integer = System.Windows.Forms.TextRenderer.MeasureText( _
                                              LiSub.Text, LiSub.Font).Width
         Return w + 5
      End Function

[LucasCain]

have you tried filling that up with any content?

[LucasCain]

Also, I just noticed, it's stuck in an infinite loop constantly redrawing.