I’m trying to Add a button or picturebox to a custom component ComboBox so that it closes the dropdown button in vb.net and I don’t want to use usercontrol

because I created a custom dropdown so it doesn’t exist if it’s a closed state.

Is it possible to apply?

I found the code in the link below from @Jimi and I combined it with my code

text

Please Guide me

Thanks

Imports System.ComponentModel
Imports System.Runtime.InteropServices

Public Class FlatComboBox2
    Inherits ComboBox
    Private customButton As Button = Nothing
    Public Event CustomButtonClicked As EventHandler(Of EventArgs)

    Public Sub New()
        customButton = New Button() With {
            .Image = My.Resources.icons8_checkmark_32,
            .ImageAlign = ContentAlignment.MiddleCenter,
            .FlatStyle = FlatStyle.Flat,
            .Parent = Me
        }
        customButton.FlatAppearance.BorderSize = 0
        AddHandler customButton.Click, AddressOf CustomButton_Click
    End Sub
    <DefaultValue(4)>
    Protected Friend Property EditControlOffset As Integer = 4

    Protected Overrides Sub OnHandleCreated(ByVal e As EventArgs)
        MyBase.OnHandleCreated(e)
        UpdateControlsPosition()
    End Sub


    Private Sub UpdateControlsPosition()
        If customButton IsNot Nothing Then
            SuspendLayout()
            Dim editRect As Rectangle
            Dim editHwnd As IntPtr
            Dim arrowRect As Rectangle = GetComboBoxInfoInternal(Handle, editRect, editHwnd)
            If arrowRect.IsEmpty OrElse editRect.IsEmpty Then
                Return
            End If
            ' Same size as the Arrow Button: change as required
            customButton.Size = arrowRect.Size
            customButton.Location = New Point(arrowRect.Left - customButton.Width - 1, 1)
            editRect.Width = ClientSize.Width - customButton.Width * 2 - EditControlOffset
            SetWindowPos(editHwnd, IntPtr.Zero, 0, 0, editRect.Width, editRect.Height, SWP_Flags)
            ResumeLayout(False)
        End If
    End Sub
    Private Sub CustomButton_Click(ByVal sender As Object, ByVal e As EventArgs)
        OnEditButtonClicked(e)
    End Sub

    Protected Overridable Sub OnEditButtonClicked(ByVal e As EventArgs)
        RaiseEvent CustomButtonClicked(Me, e)
    End Sub
    Private Const SWP_NOMOVE As Integer = &H2
    Private Const SWP_NOZORDER As Integer = &H4
    Private Const SWP_SHOWWINDOW As Integer = &H40
    Private Const SWP_Flags As Integer = SWP_NOMOVE Or SWP_NOZORDER
    Private Const WM_DESTROY As Integer = &H2
    Private Const WM_WINDOWPOSCHANGED As Integer = &H47

    <DllImport("user32.dll", CharSet:=CharSet.Auto)>
    Friend Shared Function GetComboBoxInfo(ByVal hWnd As IntPtr, ByRef pcbi As COMBOBOXINFO) As Boolean
    End Function

    <DllImport("user32.dll", SetLastError:=True)>
    Friend Shared Function SetWindowPos(ByVal hWnd As IntPtr, ByVal hWndInsertAfter As IntPtr, ByVal x As Integer, ByVal y As Integer, ByVal cx As Integer, ByVal cy As Integer, ByVal uFlags As Integer) As Boolean
    End Function
    <StructLayout(LayoutKind.Sequential)>
    Friend Structure COMBOBOXINFO
        Public cbSize As Integer
        Public rcItem As RECT
        Public rcButton As RECT
        Public buttonState As Integer
        Public hwndCombo As IntPtr
        Public hwndEdit As IntPtr
        Public hwndList As IntPtr
        'public COMBOBOXINFO() => cbSize = Marshal.SizeOf<COMBOBOXINFO>();
    End Structure

    Friend Shared Function GetComboBoxInfoInternal(ByVal cboHandle As IntPtr, ByRef editRect As Rectangle, ByRef editHandle As IntPtr) As Rectangle
        Dim cbInfo = New COMBOBOXINFO() With {.cbSize = Marshal.SizeOf(Of COMBOBOXINFO)()}
        GetComboBoxInfo(cboHandle, cbInfo)
        editHandle = cbInfo.hwndEdit
        editRect = cbInfo.rcItem.ToRectangle()
        Return cbInfo.rcButton.ToRectangle()
    End Function

    Private _borderColor As Color = Color.Green
    <DefaultValue(GetType(Color), "Green")>
    Public Property BorderColor As Color
        Get
            Return _borderColor
        End Get
        Set(ByVal value As Color)
            If _borderColor <> value Then
                _borderColor = value
                Invalidate()
            End If
        End Set
    End Property
    Private _buttonColor As Color = Color.LightGray
    <DefaultValue(GetType(Color), "LightGray")>
    Public Property ButtonColor As Color
        Get
            Return _buttonColor
        End Get
        Set(ByVal value As Color)
            If _buttonColor <> value Then
                _buttonColor = value
                Invalidate()
            End If
        End Set
    End Property
    Protected Overrides Sub WndProc(ByRef m As Message)
        If m.Msg = WM_PAINT AndAlso DropDownStyle <> ComboBoxStyle.Simple Then
            Dim clientRect = ClientRectangle
            Dim dropDownButtonWidth = SystemInformation.HorizontalScrollBarArrowWidth
            Dim outerBorder = New Rectangle(clientRect.Location, New Size(clientRect.Width - 1, clientRect.Height - 1))
            Dim innerBorder = New Rectangle(outerBorder.X + 1, outerBorder.Y + 1, outerBorder.Width - dropDownButtonWidth - 2, outerBorder.Height - 2)
            Dim innerInnerBorder = New Rectangle(innerBorder.X + 1, innerBorder.Y + 1, innerBorder.Width - 2, innerBorder.Height - 2)
            Dim dropDownRect = New Rectangle(innerBorder.Right + 1, innerBorder.Y, dropDownButtonWidth, innerBorder.Height + 1)
            If RightToLeft = RightToLeft.Yes Then
                innerBorder.X = clientRect.Width - innerBorder.Right
                innerInnerBorder.X = clientRect.Width - innerInnerBorder.Right
                dropDownRect.X = clientRect.Width - dropDownRect.Right
                dropDownRect.Width += 1
            End If
            Dim innerBorderColor = If(Enabled, BackColor, SystemColors.Control)
            Dim outerBorderColor = If(Enabled, BorderColor, SystemColors.ControlDark)
            Dim buttonColor As Color = If(Enabled, Me.ButtonColor, SystemColors.Control)
            Dim middle = New Point(dropDownRect.Left + dropDownRect.Width  2, dropDownRect.Top + dropDownRect.Height  2)
            Dim arrow = New Point() {
                New Point(middle.X - 3, middle.Y - 2),
                New Point(middle.X + 4, middle.Y - 2),
                New Point(middle.X, middle.Y + 2)
            }
            Dim ps = New PAINTSTRUCT()
            Dim shoulEndPaint As Boolean = False
            Dim dc As IntPtr
            If m.WParam = IntPtr.Zero Then
                dc = BeginPaint(Handle, ps)
                m.WParam = dc
                shoulEndPaint = True
            Else
                dc = m.WParam
            End If
            Dim rgn = CreateRectRgn(innerInnerBorder.Left, innerInnerBorder.Top, innerInnerBorder.Right, innerInnerBorder.Bottom)
            SelectClipRgn(dc, rgn)
            DefWndProc(m)
            DeleteObject(rgn)
            rgn = CreateRectRgn(clientRect.Left, clientRect.Top, clientRect.Right, clientRect.Bottom)
            SelectClipRgn(dc, rgn)
            Using g = Graphics.FromHdc(dc)
                Using b = New SolidBrush(buttonColor)
                    g.FillRectangle(b, dropDownRect)
                End Using
                Using b = New SolidBrush(outerBorderColor)
                    g.FillPolygon(b, arrow)
                End Using
                Using p = New Pen(innerBorderColor)
                    g.DrawRectangle(p, innerBorder)
                    g.DrawRectangle(p, innerInnerBorder)
                End Using
                Using p = New Pen(outerBorderColor)
                    g.DrawRectangle(p, outerBorder)
                End Using
            End Using
            If shoulEndPaint Then
                EndPaint(Handle, ps)
            End If
            DeleteObject(rgn)
        Else
            MyBase.WndProc(m)
        End If
    End Sub

    Private Const WM_PAINT As Integer = &HF
    <StructLayout(LayoutKind.Sequential)>
    Public Structure RECT
        Public L, T, R, B As Integer
        Public Sub New(ByVal left As Integer, ByVal top As Integer, ByVal right As Integer, ByVal bottom As Integer)
            Me.L = left
            Me.T = top
            Me.R = right
            Me.B = bottom
        End Sub
        Public Shared Function FromRectangle(ByVal rect As Rectangle) As RECT
            Return New RECT(rect.X, rect.Y, rect.Right, rect.Bottom)
        End Function
        Public Function ToRectangle() As Rectangle
            Return Rectangle.FromLTRB(L, T, R, B)
        End Function

    End Structure
    <StructLayout(LayoutKind.Sequential)>
    Public Structure PAINTSTRUCT
        Public hdc As IntPtr
        Public fErase As Boolean
        Public rcPaint_left As Integer
        Public rcPaint_top As Integer
        Public rcPaint_right As Integer
        Public rcPaint_bottom As Integer
        Public fRestore As Boolean
        Public fIncUpdate As Boolean
        Public reserved1 As Integer
        Public reserved2 As Integer
        Public reserved3 As Integer
        Public reserved4 As Integer
        Public reserved5 As Integer
        Public reserved6 As Integer
        Public reserved7 As Integer
        Public reserved8 As Integer
    End Structure
    <DllImport("user32.dll")>
    Private Shared Function BeginPaint(ByVal hWnd As IntPtr, <[In], [Out]> ByRef lpPaint As PAINTSTRUCT) As IntPtr
    End Function

    <DllImport("user32.dll")>
    Private Shared Function EndPaint(ByVal hWnd As IntPtr, ByRef lpPaint As PAINTSTRUCT) As Boolean
    End Function

    <DllImport("gdi32.dll")>
    Public Shared Function SelectClipRgn(ByVal hDC As IntPtr, ByVal hRgn As IntPtr) As Integer
    End Function

    <DllImport("user32.dll")>
    Public Shared Function GetUpdateRgn(ByVal hwnd As IntPtr, ByVal hrgn As IntPtr, ByVal fErase As Boolean) As Integer
    End Function
    Public Enum RegionFlags
        [ERROR] = 0
        NULLREGION = 1
        SIMPLEREGION = 2
        COMPLEXREGION = 3
    End Enum
    <DllImport("gdi32.dll")>
    Friend Shared Function DeleteObject(ByVal hObject As IntPtr) As Boolean
    End Function

    <DllImport("gdi32.dll")>
    Private Shared Function CreateRectRgn(ByVal x1 As Integer, ByVal y1 As Integer, ByVal x2 As Integer, ByVal y2 As Integer) As IntPtr
    End Function
End Class

Image

Result from code

Desired result first (with empty button or picturebox)

Desired result Second