Delete Line

Dear All,
How to remove a line from the richtextbox, by passing the line number in API Sendmessage?

Here's something from the API guide that I modified to do what you want.

VB Code:

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function SendMessageStr Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As String) As Long
Private Const EM_GETLINE = &HC4
Private Const EM_GETLINECOUNT = &HBA
Private Const EM_LINEINDEX = &HBB
Private Const EM_LINELENGTH = &HC1
Private Sub Command1_Click()
    Dim lngCount As Long
    Dim lngLineIndex As Long
    Dim lngLength As Long
    Dim strBuffer As String
    Dim strRichText As String
    Dim i As Integer
    'Get Line count
    lngCount = SendMessage(RichTextBox1.hwnd, EM_GETLINECOUNT, 0, 0)
    With RichTextBox1
        For i = 0 To lngCount - 1
            If i <> 1 Then ' If you wanted to get rid of the second line
                'Get line index
                lngLineIndex = SendMessage(.hwnd, EM_LINEINDEX, i, 0)
                'get line length
                lngLength = SendMessage(.hwnd, EM_LINELENGTH, lngLineIndex, 0)
                'resize buffer
                strBuffer = Space(lngLength)
                'get line text
                Call SendMessageStr(.hwnd, EM_GETLINE, i, ByVal strBuffer)
                'Accumulate the text to be kept
                strRichText = strRichText & strBuffer & vbCrLf
            End If
        Next
        'rewrite text in RichTextBox
        .Text = strRichText
    End With
End Sub

My version

VB Code:

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
            (ByVal hwnd As Long, ByVal wMsg As Long, _
             ByVal wParam As Long, lParam As Any) As Long
 
Private Declare Function LockWindowUpdate Lib "user32" (ByVal hwndLock As Long) As Long
 
Private Const EM_SETSEL = &HB1
Private Const EM_GETLINECOUNT = &HBA
Private Const EM_LINEINDEX = &HBB
 
Private Sub DeleteLine(pLineNumber As Long)
    Dim chrsToStart As Long, chrsToEnd As Long, lineCount As Long
    
    With RichTextBox1
        lineCount = SendMessage(.hwnd, EM_GETLINECOUNT, 0, ByVal 0&)
        
        Select Case True
            Case pLineNumber > lineCount - 1
                Exit Sub
            Case pLineNumber = 0 And lineCount = 1
                chrsToStart = 0
                chrsToEnd = Len(.Text)
            Case pLineNumber = lineCount - 1
                chrsToStart = SendMessage(.hwnd, EM_LINEINDEX, pLineNumber, ByVal 0&) - 1
                chrsToEnd = Len(.Text) - chrsToStart + 1
            Case Else
                chrsToStart = SendMessage(.hwnd, EM_LINEINDEX, pLineNumber, ByVal 0&)
                chrsToEnd = SendMessage(.hwnd, EM_LINEINDEX, pLineNumber + 1, ByVal 0&) - chrsToStart
        End Select
                             
        .SetFocus
        Call SendMessage(.hwnd, EM_SETSEL, chrsToStart, ByVal chrsToEnd)
        
        LockWindowUpdate .hwnd
            .SelStart = chrsToStart
            .SelLength = chrsToEnd
            .SelText = vbNullString
        LockWindowUpdate False
    End With
End Sub
 
Private Sub Command1_Click()
    DeleteLine 2 'Deletes line 2 (its the third line, because first line is line 0)
End Sub

Dear Martin,
Will this support a datasize of 4MB.In the meanwhile I am trying JCIS code :)

Quote:

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Originally Posted by danasegarane

Dear Martin,
Will this support a datasize of 4MB.In the meanwhile I am trying JCIS code :)

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Sorry but I have no idea.

Great stuff guys. The only problem now is that it changes all the color.
now what could be a good work around for that one?