transparent RadTextBox with round corners and customized scrollbars

[mdanh]

Hi

Is it possible to have a RadTextBox that has rounded corners, transparent background and cusomized scrollbars. I have tried the Theme Builder but could not find any satisfactory way to do it.

Look forward to any hints.
Thanks

[Stefan]

Hi mdanh,

Thank you for contacting us.

You can easily make the corners of RadTextBox rounded through applying a RectangleShape to the Shape property of RadTextBoxElement. Please refer to the attached screenshot. 

However, I am afraid that you will not be able to make RadTextBox transparent or customize its scrollbars. The reason is that internally we are using a standard Microsoft textbox which is not flexible for any modifications of this kind. Please excuse us for the caused inconvenience.

If there is anything else we can help you with, do not hesitate to contact us.

Regards,
Stefan
the Telerik team

[mdanh]

Thanks for the reply.

I understand that the scrollbars could not be easily customized. However, are there any possibilities for the transparent background? I found on the internet the source code of AlphaBlendTextbox that works reasonably well for normal .NET textbox. I tried to apply it to RadTextBox and the result is a broken RadTextBox that has no transparency and unexpected behaviour. Refer to source code below. If the class inherits from TextBox, not RadTextBox, everything works resonably well.

Do you perhaps know what I did wrongly, or are there any fundamental differences between .NET TextBox and RadTextBox that make it impossible to apply similar effects to RadTextBox?

Thanks for any hints.

Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.Drawing
Imports System.Data
Imports System.Windows.Forms
Imports System.Drawing.Imaging
Imports System.Runtime.InteropServices
Imports Telerik.WinControls.UI

''' <summary>
''' AlphaBlendTextBox: A .Net textbox that can be translucent to the background.
''' </summary>
''' <remarks>
''' Source code taken from http://www.codeproject.com/KB/edit/alphablendtextbox.aspx
''' and was converted to VB.NET by Minh Danh
'''</remarks>
Public Class AlphaBlendTextBox
    Inherits RadTextBox

#Region "Private variables"

    Private myPictureBox As uPictureBox
    Private myUpToDate As Boolean = False
    Private myCaretUpToDate As Boolean = False
    Private myBitmap As Bitmap
    Private myAlphaBitmap As Bitmap

    Private myFontHeight As Integer = 10

    Private myTimer1 As System.Windows.Forms.Timer

    Private myCaretState As Boolean = True

    Private myPaintedFirstTime As Boolean = False

    Private myBackColor As Color = Color.White
    Private myBackAlpha As Integer = 10

    ''' <summary>
    ''' Required designer variable.
    ''' </summary>
    Private components As System.ComponentModel.Container = Nothing
#End Region

#Region "Public methods and overrides"
    Public Sub New()
        ' This call is required by the Windows.Forms Form Designer.
        InitializeComponent()
        ' TODO: Add any initialization after the InitializeComponent call

        Me.BackColor = myBackColor

        Me.SetStyle(ControlStyles.UserPaint, False)
        Me.SetStyle(ControlStyles.AllPaintingInWmPaint, True)
        Me.SetStyle(ControlStyles.DoubleBuffer, True)


        myPictureBox = New uPictureBox()
        Me.Controls.Add(myPictureBox)
        myPictureBox.Dock = DockStyle.Fill
    End Sub

    Protected Overloads Overrides Sub OnResize(ByVal e As EventArgs)

        MyBase.OnResize(e)
        Me.myBitmap = New Bitmap(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
        '(this.Width,this.Height);
        Me.myAlphaBitmap = New Bitmap(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
        '(this.Width,this.Height);
        myUpToDate = False
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub OnKeyDown(ByVal e As KeyEventArgs)
        MyBase.OnKeyDown(e)
        myUpToDate = False
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub OnKeyUp(ByVal e As KeyEventArgs)
        MyBase.OnKeyUp(e)
        myUpToDate = False
        Me.Invalidate()

    End Sub

    Protected Overloads Overrides Sub OnKeyPress(ByVal e As KeyPressEventArgs)
        MyBase.OnKeyPress(e)
        myUpToDate = False
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
        MyBase.OnMouseUp(e)
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub OnGiveFeedback(ByVal gfbevent As GiveFeedbackEventArgs)
        MyBase.OnGiveFeedback(gfbevent)
        myUpToDate = False
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub OnMouseLeave(ByVal e As EventArgs)
        Try
            'found this code to find the current cursor location
            'at http://www.syncfusion.com/FAQ/WinForms/FAQ_c50c.asp#q597q

            Dim ptCursor As Point = Cursor.Position

            Dim f As Form = Me.FindForm()
            ptCursor = f.PointToClient(ptCursor)
            If Not Me.Bounds.Contains(ptCursor) Then
                MyBase.OnMouseLeave(e)
            End If
        Catch ex As Exception
        End Try
    End Sub

    Protected Overloads Overrides Sub OnChangeUICues(ByVal e As UICuesEventArgs)
        MyBase.OnChangeUICues(e)
        myUpToDate = False
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub OnGotFocus(ByVal e As EventArgs)
        MyBase.OnGotFocus(e)
        myCaretUpToDate = False
        myUpToDate = False
        Me.Invalidate()


        myTimer1 = New System.Windows.Forms.Timer(Me.components)

        myTimer1.Interval = CInt(Win32.GetCaretBlinkTime())

        '  usually around 500;
        AddHandler myTimer1.Tick, AddressOf myTimer1_Tick
        myTimer1.Enabled = True
    End Sub

    Protected Overloads Overrides Sub OnLostFocus(ByVal e As EventArgs)
        MyBase.OnLostFocus(e)
        myCaretUpToDate = False
        myUpToDate = False
        Me.Invalidate()

        myTimer1.Dispose()
    End Sub

    Protected Overloads Overrides Sub OnFontChanged(ByVal e As EventArgs)
        If Me.myPaintedFirstTime Then
            Me.SetStyle(ControlStyles.UserPaint, False)
        End If

        MyBase.OnFontChanged(e)

        If Me.myPaintedFirstTime Then
            Me.SetStyle(ControlStyles.UserPaint, True)
        End If


        myFontHeight = GetFontHeight()


        myUpToDate = False
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub OnTextChanged(ByVal e As EventArgs)
        MyBase.OnTextChanged(e)
        myUpToDate = False
        Me.Invalidate()
    End Sub

    Protected Overloads Overrides Sub WndProc(ByRef m As Message)

        MyBase.WndProc(m)

        ' need to rewrite as a big switch

        If m.Msg = Win32.WM_PAINT Then
            myPaintedFirstTime = True

            If Not myUpToDate OrElse Not myCaretUpToDate Then
                GetBitmaps()
            End If
            myUpToDate = True
            myCaretUpToDate = True

            If myPictureBox.Image IsNot Nothing Then
                myPictureBox.Image.Dispose()
            End If

            myPictureBox.Image = DirectCast(myAlphaBitmap.Clone(), Image)

        ElseIf m.Msg = Win32.WM_HSCROLL OrElse m.Msg = Win32.WM_VSCROLL Then
            myUpToDate = False
            Me.Invalidate()

        ElseIf m.Msg = Win32.WM_LBUTTONDOWN OrElse m.Msg = Win32.WM_RBUTTONDOWN OrElse m.Msg = Win32.WM_LBUTTONDBLCLK Then
            '  || m.Msg == win32.WM_MOUSELEAVE  ///****
            myUpToDate = False
            Me.Invalidate()

        ElseIf m.Msg = Win32.WM_MOUSEMOVE Then
            If m.WParam.ToInt32() <> 0 Then
                'shift key or other buttons
                myUpToDate = False
                Me.Invalidate()
            End If
        End If



        'System.Diagnostics.Debug.WriteLine("Pro: " + m.Msg.ToString("X"));

    End Sub

    ''' <summary>
    ''' Clean up any resources being used.
    ''' </summary>
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            'this.BackColor = Color.Pink;
            If components IsNot Nothing Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
#End Region

#Region "Public property overrides"

    Public Shadows Property BackColor() As Color
        Get
            Return Color.FromArgb(MyBase.BackColor.R, MyBase.BackColor.G, MyBase.BackColor.B)
        End Get
        Set(ByVal value As Color)
            myBackColor = value
            MyBase.BackColor = value
            myUpToDate = False
        End Set
    End Property

#End Region

#Region "Private functions and classes"

    Private Function GetFontHeight() As Integer
        Dim g As Graphics = Me.CreateGraphics()
        Dim sf_font As SizeF = g.MeasureString("X", Me.Font)
        g.Dispose()
        Return CInt(sf_font.Height)
    End Function

    Private Sub GetBitmaps()

        If myBitmap Is Nothing OrElse myAlphaBitmap Is Nothing OrElse myBitmap.Width <> Width OrElse myBitmap.Height <> Height OrElse myAlphaBitmap.Width <> Width OrElse

myAlphaBitmap.Height <> Height Then
            myBitmap = Nothing
            myAlphaBitmap = Nothing
        End If

        If myBitmap Is Nothing Then
            myBitmap = New Bitmap(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
            '(Width,Height);
            myUpToDate = False
        End If


        If Not myUpToDate Then
            'Capture the TextBox control window

            Me.SetStyle(ControlStyles.UserPaint, False)

            Win32.CaptureWindow(Me, myBitmap)

            Me.SetStyle(ControlStyles.UserPaint, True)
            Me.SetStyle(ControlStyles.SupportsTransparentBackColor, True)

            Me.BackColor = Color.FromArgb(myBackAlpha, myBackColor)
        End If
        '--



        Dim r2 As New Rectangle(0, 0, Me.ClientRectangle.Width, Me.ClientRectangle.Height)
        Dim tempImageAttr As New ImageAttributes()

        'Found the color map code in the MS Help
        'tempColorMap is an array having only 1 element, index starting from 0
        'original C# code: ColorMap[] tempColorMap = new ColorMap[1];
        Dim tempColorMap As ColorMap() = New ColorMap(0) {}
        tempColorMap(0) = New ColorMap()
        tempColorMap(0).OldColor = Color.FromArgb(255, myBackColor)
        tempColorMap(0).NewColor = Color.FromArgb(myBackAlpha, myBackColor)

        tempImageAttr.SetRemapTable(tempColorMap)

        If myAlphaBitmap IsNot Nothing Then
            myAlphaBitmap.Dispose()
        End If


        myAlphaBitmap = New Bitmap(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
        '(Width,Height);
        Dim tempGraphics1 As Graphics = Graphics.FromImage(myAlphaBitmap)

        tempGraphics1.DrawImage(myBitmap, r2, 0, 0, Me.ClientRectangle.Width, Me.ClientRectangle.Height, _
         GraphicsUnit.Pixel, tempImageAttr)

        tempGraphics1.Dispose()

        '----

        If Me.Focused AndAlso (Me.SelectionLength = 0) Then
            Dim tempGraphics2 As Graphics = Graphics.FromImage(myAlphaBitmap)
            If myCaretState Then
                'Draw the caret
                Dim caret As Point = Me.findCaret()
                Dim p As New Pen(Me.ForeColor, 3)
                tempGraphics2.DrawLine(p, caret.X, caret.Y + 0, caret.X, caret.Y + myFontHeight)
                tempGraphics2.Dispose()

            End If
        End If



    End Sub

    Private Function findCaret() As Point
        '  Find the caret translated from code at
        '            * http://www.vb-helper.com/howto_track_textbox_caret.html
        '            *
        '            * and
        '            *
        '            * http://www.microbion.co.uk/developers/csharp/textpos2.htm
        '            *
        '            * Changed to EM_POSFROMCHAR
        '            *
        '            * This code still needs to be cleaned up and debugged
        '            *


        Dim pointCaret As New Point(0)
        Dim i_char_loc As Integer = Me.SelectionStart
        Dim pi_char_loc As New IntPtr(i_char_loc)

        Dim i_point As Integer = Win32.SendMessage(Me.Handle, Win32.EM_POSFROMCHAR, pi_char_loc, IntPtr.Zero)
        pointCaret = New Point(i_point)

        If i_char_loc = 0 Then
            pointCaret = New Point(0)
        ElseIf i_char_loc >= Me.Text.Length Then
            pi_char_loc = New IntPtr(i_char_loc - 1)
            i_point = Win32.SendMessage(Me.Handle, Win32.EM_POSFROMCHAR, pi_char_loc, IntPtr.Zero)
            pointCaret = New Point(i_point)

            Dim g As Graphics = Me.CreateGraphics()
            Dim t1 As [String] = Me.Text.Substring(Me.Text.Length - 1, 1) + "X"
            Dim sizet1 As SizeF = g.MeasureString(t1, Me.Font)
            Dim sizex As SizeF = g.MeasureString("X", Me.Font)
            g.Dispose()
            Dim xoffset As Integer = CInt(sizet1.Width - sizex.Width)
            pointCaret.X = pointCaret.X + xoffset

            If i_char_loc = Me.Text.Length Then
                Dim slast As [String] = Me.Text.Substring(Text.Length - 1, 1)
                If slast = vbLf Then
                    pointCaret.X = 1
                    pointCaret.Y = pointCaret.Y + myFontHeight
                End If

            End If
        End If



        Return pointCaret
    End Function

    Private Sub myTimer1_Tick(ByVal sender As Object, ByVal e As EventArgs)
        'Timer used to turn caret on and off for focused control

        myCaretState = Not myCaretState
        myCaretUpToDate = False
        Me.Invalidate()
    End Sub

    Private Class uPictureBox
        Inherits PictureBox
        Public Sub New()
            Me.SetStyle(ControlStyles.Selectable, False)
            Me.SetStyle(ControlStyles.UserPaint, True)
            Me.SetStyle(ControlStyles.AllPaintingInWmPaint, True)
            Me.SetStyle(ControlStyles.DoubleBuffer, True)

            Me.Cursor = Nothing
            Me.Enabled = True

            Me.SizeMode = PictureBoxSizeMode.Normal
        End Sub

        'uPictureBox
        Protected Overloads Overrides Sub WndProc(ByRef m As Message)
            If m.Msg = Win32.WM_LBUTTONDOWN OrElse m.Msg = Win32.WM_RBUTTONDOWN OrElse m.Msg = Win32.WM_LBUTTONDBLCLK OrElse m.Msg =

Win32.WM_MOUSELEAVE OrElse m.Msg = Win32.WM_MOUSEMOVE Then
                'Send the above messages back to the parent control
                Win32.PostMessage(Me.Parent.Handle, CUInt(m.Msg), m.WParam, m.LParam)

            ElseIf m.Msg = Win32.WM_LBUTTONUP Then
                '??  for selects and such
                Me.Parent.Invalidate()
            End If


            MyBase.WndProc(m)
        End Sub
    End Class
#End Region

#Region "Component Designer generated code"
    ''' <summary>
    ''' Required method for Designer support - do not modify
    ''' the contents of this method with the code editor.
    ''' </summary>
    Private Sub InitializeComponent()
        components = New System.ComponentModel.Container()
    End Sub
#End Region

#Region "New Public Properties"
    <Category("Appearance"), Description("The alpha value used to blend the control's background. Valid values are 0 through 255."), Browsable(True), DesignerSerializationVisibility

(DesignerSerializationVisibility.Visible)> _
    Public Property BackAlpha() As Integer
        Get
            Return myBackAlpha
        End Get
        Set(ByVal value As Integer)
            Dim v As Integer = value
            If v > 255 Then
                v = 255
            End If
            myBackAlpha = v
            myUpToDate = False
            Invalidate()
        End Set
    End Property
#End Region
End Class

[Boryana]

Hi mdanh,

Thank you for writing back.

Our team tested the original AlphaBlendTextBox project and we found that the following three slight modifications are needed for the code to work with RadTextBox:

• The AlphaBlendTextBox should inherit HostedTextBoxBase, instead of RadTextBox.
• The internal TextBox in our RadTextBox should be substituted with the custom AlphaBlendTextBox. Here is a sample snippet:

Me.radTextBox1.TextBoxElement.Children.RemoveAt(0)
Dim item As New RadTextBoxItem(New AlphaBlendTextBox())
Me.radTextBox1.TextBoxElement.Children.Insert(0, item)

• The BackColor properties of the RadTextBox and the its FillPrimitive should be set to Transparent.

Me.radTextBox1.BackColor = Color.Transparent;
Me.radTextBox1.TextBoxElement.Fill.BackColor = Color.Transparent;

I hope you will find this helpful. Let me know if you have further questions. I will be glad to assist you.

Kind regards,
Boryana
the Telerik team

[mdanh]

Thanks so much for the suggestions and code snippet. I have been able to make AlphaBlendTextbox work with RadTextBox.

[Nikolay]

Hi mdanh,

We are glad to hear that our solution was helpful. If you have additional questions, feel free to contact us.

Sincerely yours,
Nikolay
the Telerik team

[mdanh]

Hi

I found a problem.

When using the code snippet you gave, the property Nulltext of the original RadTextBox does not work - nothing is shown. I have tried to change NullText and NullTextColor to no avail. Also is there a way to change the forecolor and backcolor of the selected text (it seems distorted)? It was not found in "Edit UI Elements" and trying to use theme builder on this modified RadTextBox results in a distorted RadTextBox. If the color cannot be change, how can I simply disable text selection (via mouse and keyboard)?

[Nikolay]

Hello mdanh,

Thank you for getting back to us.

The text selection is a feature of the Microsoft TextBox and we do not have control over it. As to the NullText and NullTextColor, the process of replacing the internal RadTextBoxItem with a custom one breaks the internal property synchronization. Therefore, you need to set these properties directly to the AlphaBlendTextBox instance:

Me.radTextBox1.TextBoxElement.Children.RemoveAt(0)
Dim abtb As New AlphaBlendTextBox()
Dim item As New RadTextBoxItem(abtb)
Me.radTextBox1.TextBoxElement.Children.Insert(0, item)

Me.radTextBox1.BackColor = Color.Transparent
Me.radTextBox1.TextBoxElement.Fill.BackColor = Color.Transparent

abtb.NullText = "NullText"
abtb.NullTextColor = Color.Green

All the best,
Nikolay
the Telerik team