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How can I Optimize Loop through Lines of MultiLine Textbox

How can I Optimize Loop through Lines of MultiLine Textbox, I want to loop each line of multiline textbox so I can check if all li

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RuleS	10 Oct, 2008 - 11:27 PM Post #1
New D.I.C Head Joined: 28 Mar, 2008 Posts: 5	Hi All, I 'm currently developing program which I can check the lines of each textbox if it has same length. The code is working properly in few lines like 2000 lines, but when I try to load a textfile which has 50,000 lines, my program is not responding anymore it takes forever. Is there anything you could help me to make it faster? Pls. its the only logic I could think of. CODE Private Sub LineChecker() Dim counter As Integer = TextBox1.Lines.Length - 1 Dim intArray(counter) As Integer Dim iLine, i As Integer For iLine = 0 To counter - 1 If TextBox1.Lines(iLine).Length <> 534 Then listbox1.items.add(iLine) End If Next iLine If iLine = TextBox1.Lines.Length Then MsgBox("Checking lines complete") End If End Sub Any help I will appreciate. Thanks, Ruel This post has been edited by RuleS: 10 Oct, 2008 - 11:34 PM
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Damage	11 Oct, 2008 - 03:54 AM Post #2
D.I.C Addict Joined: 5 Jun, 2008 Posts: 728 Thanked 7 times Dream Kudos: 75 My Contributions	dude, 50,000 lines is always going to take some time, no matter what you do
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magicmonkey	11 Oct, 2008 - 11:45 AM Post #3
D.I.C Regular Joined: 12 Sep, 2008 Posts: 374 Thanked 64 times My Contributions	You can make this much faster but show us how you are loading the textfile into the textbox first.
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dbasnett	12 Oct, 2008 - 04:57 AM Post #4
D.I.C Head Joined: 1 Oct, 2008 Posts: 131 Thanked 5 times My Contributions	i have found that RichTextBox is faster than TextBox.
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RuleS	12 Oct, 2008 - 06:04 PM Post #5
New D.I.C Head Joined: 28 Mar, 2008 Posts: 5	Hi Dude, I load my textfile with copying the content of text file and paste it in textbox control or with this code: CODE Dim fName As String Dim objStreamReader As StreamReader Private Sub FileOpen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles FileOpen.Click Try If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then fName = OpenFileDialog1.FileName objStreamReader = New StreamReader(OpenFileDialog1.OpenFile) TextBox1.AppendText(objStreamReader.ReadToEnd) End If 'End If Catch ex As Exception MsgBox(ex.Message) End Try End Sub I know that 50,000 lines would take time, but as I have observed, when I run this application and fire the event, it take more than 3 hours and still processing......I need to check the lines for at most 30 minutes. Thanks, RuleS
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magicmonkey

13 Oct, 2008 - 11:13 AM

Post #6

D.I.C Regular

Joined: 12 Sep, 2008
Posts: 374

Windows

Thanked 64 times
My Contributions

The textbox control is not meant to handle that amount of data, using the richtextbox control as well as checking for the failed lines as we read from the datafile the code below should accomplish the same task in under 5 seconds. Depending on your needs a cleaner look may be to highlight the lines in the richtextbox that dont meet you length requirements instead of placing them in a list box.

You have to be very careful when manipulating strings in .NET as they are a value type object and almost everytime you access them .Net creates a copy of the value type, that is why .NET has a stringbuilder class, I tried to demonstrate a good way to use it below.


 Try
            Dim OpenFileDialog As New OpenFileDialog
            If OpenFileDialog.ShowDialog = Windows.Forms.DialogResult.OK Then

                Using fileStreamReader = New StreamReader(OpenFileDialog.FileName)
                    Dim fileStringBuilder As New System.Text.StringBuilder
                    Dim failedLines As New List(Of String)
                    Dim readLine As String

                    Do Until fileStreamReader.EndOfStream
                        'Read a line from file
                        readLine = fileStreamReader.ReadLine
                        'Append line to string builder
                        fileStringBuilder.AppendLine(readLine)
                        'Check if line meets conditions
                        If readLine.Length > 50 Then
                            'Add failed line to string collection
                            failedLines.Add(readLine)
                        End If
                    Loop

                    'Populate richtextbox from string builder
                    RichTextBox1.Text = fileStringBuilder.ToString

                    'Append failed lines to listbox
                    ListBox1.BeginUpdate()
                    ListBox1.Items.AddRange(failedLines.ToArray)
                    ListBox1.EndUpdate()
                End Using
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try

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RuleS	15 Oct, 2008 - 04:31 PM Post #7
New D.I.C Head Joined: 28 Mar, 2008 Posts: 5	Thank you very much MagicMonkey, I tried your code and really it is much faster. It really ease my work.
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