VB.NET search in richtextbox

Question

Hello everyone!!!

Do you know if there is a way, within a richtextbox, to select all text with a particular formatting?

For example I would like to select all text in bold or all text in red ... (and after remove formatting)

Thanks in advance to everyone.

Answer 1

Hi @manuel angeli ,

After my tests, Color.Aqua and Color.Cyan are both the same color #FF00FFFF, and use txt_note.SelectionBackColor always gets Color.Aqua when getting the background color, so you should use the following code to determine the background color.

            If txt_note.SelectionBackColor = Color.Aqua Then
                txt_note.Select(i + 1, 1)
                txt_note.SelectionBackColor = Color.Green
            End If

Best Regards.

Jiachen Li

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Answer 2

Hi

Here is some code that may be helpful. This is a stand alone example and you need to try it before using it. To try it, start a new test Project, on Form1 put a RichTextBox named RTB, a default ComboBox1, Button1 and a ContextMenuStrip with "RED, LIGHT BLUE, GREEN and WHITE" items on it.

The idea here is: user selects a word and a colour from the ComboBox then clicks the 'CUT" button. With luck, all words matching selected word and matching selected colour will disappear.

There are lots of variations possible, this being one of them.

There is also a ContextMenu to enable a colour selection (just a simple choice) for testing purposes. Just select a word or some text and then right click for the colour choices. (colour options would normally be much more comprehensive in a real world application)

Option Strict On
Option Explicit On
Public Class Form1
	Dim path As String = IO.Path.Combine(Application.StartupPath, "RTB.rtf")
	Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing

		' if you want to save on close - uncomment
		RTB.SaveFile(path, RichTextBoxStreamType.RichText)
	End Sub
	Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
		With RTB
			' to load previously saved text - uncomment
			'If IO.File.Exists(path) Then
			'	.LoadFile(path)
			'End If

			.ContextMenuStrip = ContextMenuStrip1
			.ShowSelectionMargin = True
			.ZoomFactor = 2.5

			' some sample text for testing with
			.Text = "This Is some example text To illustrate the slow unreliable way To Select And delete all words which have a given text colour.

There may well be other ways To Do this which may also be far better than this way, but I have never noticed them in the past."
		End With

		With ComboBox1
			.Items.AddRange({"RED", "LIGHT BLUE", "GREEN", "WHITE"})
			.SelectedIndex = 0
		End With
	End Sub

	Private Sub ContextMenu_Click(sender As Object, e As EventArgs) Handles REDToolStripMenuItem.Click, LIGHTBLUEToolStripMenuItem.Click, GREENToolStripMenuItem.Click, WHITEToolStripMenuItem.Click

		Dim cm As ToolStripMenuItem = DirectCast(sender, ToolStripMenuItem)

		Select Case cm.Text
			Case "RED"
				RTB.SelectionColor = Color.Red
			Case "LIGHT BLUE"
				RTB.SelectionColor = Color.LightBlue
			Case "GREEN"
				RTB.SelectionColor = Color.Green
			Case "WHITE"
				RTB.SelectionColor = Color.White
		End Select
	End Sub

	Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
		Dim s As String = ComboBox1.SelectedItem.ToString

		Select Case ComboBox1.SelectedItem.ToString
			Case "RED"
				CutWords(Trim(RTB.SelectedText), Color.Red)
			Case "LIGHT BLUE"
			Case "GREEN"
			Case "WHITE"

		End Select
	End Sub
	Sub CutWords(s As String, c As Color)

		Dim words() As String = RTB.Text.Split(New String() {" ", ".", ",", vbLf, vbCr}, StringSplitOptions.RemoveEmptyEntries)

		Dim inx As Integer = 0
		For Each w As String In words
			If w = s Then
				inx = RTB.Text.IndexOf(w, inx + 1)
				RTB.Select(inx, w.Length)
				If RTB.SelectionColor = c Then
					RTB.Cut()
				End If
			End If
		Next
	End Sub
End Class

Answer 3

Hi Les, thank's for your replay!
I'll try starting by showing you the code I started with (it works pretty well), look for all bold text and change the background color to red.

For i As Integer = 0 To txt_note.Text.Length - 1
    txt_note.Select(i, 1)
    If txt_note.SelectionFont.Bold Then
        txt_note.Select(i + 1, 1)
        txt_note.SelectionBackColor = Color.Green
    End If
Next

Now I simply tried to replace this line:

If txt_note.SelectionFont.Bold Then

By changing the code in this way:

For i As Integer = 0 To txt_note.Text.Length - 1
    txt_note.Select(i, 1)
    If txt_note.SelectionBackColor = Color.Cyan Then
        txt_note.Select(i + 1, 1)
        txt_note.SelectionBackColor = Color.Green
    End If
Next

... but it doesn't work...

as you can tell from the code, what I need to do is look for text with background color (highlighted) cyan and change it to another color.

can this be a right approach what I am doing?

Answer 4

I have a form with a RTB and a button. Here is the code I used to setup the RTB to have some bold text.

    ' RTB contents
    ' Lorem ipsum dolor sit amet, appetere senserit voluptaria cu mei. Vel everti repudiandae ne, mel eu ignota malorum! 
    ' Te voluptua prodesset pro, nostrum offendit ad per. Iisque invenire assentior usu in, et simul populo labitur ius! 
    ' Eos et reque eleifend eloquentiam.

    Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
        'random setup for testing, bold some text
        Dim bf As New Font(RichTextBox1.Font.Name, RichTextBox1.Font.Size, FontStyle.Bold)
        Dim bold() As String = {"ipsum", "nostrum"}
        For Each wd As String In bold
            Dim i As Integer = 0
            Do
                i = RichTextBox1.Find(wd, i, RichTextBoxFinds.None)
                If i >= 0 Then
                    RichTextBox1.Select(i, wd.Length)
                    RichTextBox1.SelectionFont = bf
                    i += 1
                End If
            Loop While i >= 0
        Next
    End Sub

The button code highlights the bold text in yellow.

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim strtBold As Integer = -1
        Dim lenBold As Integer = 0
        For x As Integer = 0 To RichTextBox1.TextLength - 1
            RichTextBox1.Select(x, 1)
            If RichTextBox1.SelectionFont.Bold Then
                If strtBold < 0 Then
                    strtBold = x
                End If
                lenBold += 1
            ElseIf strtBold >= 0 Then
                RichTextBox1.Select(strtBold, lenBold)
                RichTextBox1.SelectionBackColor = Color.Yellow
                strtBold = -1
                lenBold = 0
            End If
        Next
    End Sub

Answer 5

Another approach that can be used for numerous conditions. I have shown bold and italic, but could be adapted for color.

    Public Class RTBSpec
        Public Property isBold As Boolean = False
        Public Property isItalic As Boolean = False
        Public Property StartPos As Integer = -1
        Public Property Length As Integer = 0
    End Class

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim Specs As New List(Of RTBSpec)
        Dim curBold As RTBSpec
        Dim curItal As RTBSpec
        For x As Integer = 0 To RichTextBox1.TextLength - 1
            RichTextBox1.Select(x, 1)
            If RichTextBox1.SelectionFont.Bold Then 'bold
                If curBold Is Nothing Then
                    curBold = New RTBSpec
                    curBold.isBold = True
                    curBold.StartPos = x
                    Specs.Add(curBold)
                End If
                curBold.Length += 1
            ElseIf curBold IsNot Nothing Then
                curBold = Nothing
            End If
            If RichTextBox1.SelectionFont.Italic Then 'italic
                If curItal Is Nothing Then
                    curItal = New RTBSpec
                    curItal.isItalic = True
                    curItal.StartPos = x
                    Specs.Add(curItal)
                End If
                curItal.Length += 1
            ElseIf curItal IsNot Nothing Then
                curItal = Nothing
            End If
        Next
        For Each rtbS As RTBSpec In Specs
            RichTextBox1.Select(rtbS.StartPos, rtbS.Length)
            If rtbS.isItalic Then
                RichTextBox1.SelectionColor = Color.Green
            ElseIf rtbS.isBold Then
                RichTextBox1.SelectionBackColor = Color.Yellow
            End If
        Next
    End Sub