Problem with this code, removing a line from an array
Code:
Imports System.IO
Public Class Form6
Private Sub SearchBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SearchBtn.Click
Dim alltext() As String = System.IO.File.ReadAllLines("C:\Users\Parent\Documents\Visual Studio 2008\Projects\Members.txt")
Dim lookfor As String = IDFilter.Text & ","
For Each line As String In Filter(alltext, lookfor)
If line.StartsWith(IDFilter.Text) Then
MemberDetails.Text = line
End If
Next
End Sub
End Class
I'm using text files as an array to store and remove information, however I do not know know how to adapt this code so the line I search for is removed.
My text files are set up as such:
021,Donovan,56 Eynesford Crescent,Bexleyheath,CT5 1TR,09/08/1967,13 March 2012,Bronze
062,Fredrikson,6 Freil Road,Gravesend,CT9 1RB,12/06/1995,13 March 2012,Silver
So I can search and locate the ID, in these cases 021 or 062, but I want to be able to remove the line I want, once it's been found. Can anyone help?
Re: Problem with this code, removing a line from an array
Typically, the way you would do this would be to remove the line from the array, then re-write the wholoe text file, as ugly as that likely sounds. Deleting items from an array isn't all that easy, either, but deleting items from a List IS! Therefore, one option would be to move the array into a list:
Code:
Dim myList as New List(of String)
myList.AddRange(alltext)
Then do your work with the list, which has a Remove and RemoveAt method. You would then write the whole thing back to the file when done.
That seems kind of painful, frankly, and there may be an easier way while still using a text file. However, your data doesn't really look like it is structured all that well for a text file. You clearly have multiple fields for each line. Therefore, you might consider using a datatable to hold the information. This would be much easier to search, add to, delete from, display (it would bind well to a DataGridView), and so forth. Furthermore, you can then store the data as an XML file (which is text with a bunch of tags larded on) with one simple method .WriteXML. You can also read the file into the datatable with ReadXML.
Re: Problem with this code, removing a line from an array
Obvioulsy Shaggy's solution is more complete and professional than what I am proposing here, but this one may be faster to code.
It is not possible to delete a line from a text file just like that. You, as Shaggy said, need to rewrite the file. So, why not write the new one while searching your array? or reading the original file line by line?
vb.net Code:
Dim alltext() As String = System.IO.File.ReadAllLines("C:\Users\Parent\Documents\Visual Studio 2008\Projects\Members.txt")
Dim lookfor As String = IDFilter.Text & ","
Dim sw As New streamwriter("C:\MyFile")
For Each line As String In Filter(alltext, lookfor)
If line.StartsWith(IDFilter.Text) Then
MemberDetails.Text = line
Else
sw.WriteLine(line)
End If
Next
Re: Problem with this code, removing a line from an array
Quote:
Originally Posted by
Shaggy Hiker
Code:
Dim myList as New List(of String)
myList.AddRange(alltext)
You could also do it as:-
vbnet Code:
Dim myList as List(of String) = alltext.ToList
Re: Problem with this code, removing a line from an array
The following is based off the format of the two lines shown in your initial question so if this is not correct the code below will not work.
Staying with your current format you could create a class (in this case named Member) that hold each member which is obtained using TextFieldParser into a List(Of Member) which becomes the source of a BindingSource component.
In the code below place a ComboBox on the form named ComboBox1 (of course later rename it to something like cboMember) and set DropDownStyle to DropDownList.
Place two buttons on your form, cmdSave and cmdRemoveMember along with a label named Label1.
Use the code below for the form where you placed the controls above. Note the form name, if your form is another name adjust as needed.
Code:
Public Class Form1
WithEvents bsMembers As New BindingSource
Private MembersFile As String = IO.Path.Combine(Application.StartupPath, "Members.txt")
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
If IO.File.Exists(MembersFile) Then
Dim MemberList As New List(Of Member)
Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser(MembersFile)
MyReader.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
MyReader.Delimiters = New String() {","}
Dim Row As String()
' If you are writing the file then all should be good here.
' If you are not writing the file then assertion would be wise.
While Not MyReader.EndOfData
Row = MyReader.ReadFields()
MemberList.Add( _
New Member With _
{ _
.Identifier = Row(0), _
.Column2 = Row(1), _
.Column3 = Row(2), _
.Column4 = Row(3), _
.Column5 = Row(4), _
.Column6 = Row(5), _
.Column7 = Row(6), _
.Column8 = Row(7) _
} _
)
End While
End Using
bsMembers.DataSource = (From T In MemberList Select T Order By T.Identifier).ToList
If bsMembers.Count > 0 Then
cmdRemoveMember.Enabled = True
ComboBox1.DisplayMember = "Identifier"
ComboBox1.DataSource = bsMembers
Else
cmdRemoveMember.Enabled = False
End If
cmdSave.DataBindings.Add("Enabled", cmdRemoveMember, "Enabled")
Else
cmdSave.Enabled = False
cmdRemoveMember.Enabled = False
My.Dialogs.InformationDialog("Failed to locate '" & MembersFile & "'")
End If
End Sub
Private Sub bsMembers_PositionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles bsMembers.PositionChanged
If bsMembers.Current IsNot Nothing Then
Label1.Text = String.Concat("Color: ", CType(bsMembers.Current, Member).Column8)
End If
End Sub
Private Sub cmdRemoveMember_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRemoveMember.Click
Dim Item = (From T In bsMembers.Cast(Of Member)() Where T.Identifier = ComboBox1.Text).FirstOrDefault
If Item IsNot Nothing Then
If My.Dialogs.Question("Remove current member?") Then
bsMembers.Remove(Item)
cmdRemoveMember.Enabled = bsMembers.Count > 0
End If
End If
End Sub
Private Sub cmdSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSave.Click
Dim sb As New System.Text.StringBuilder
For Each Member As Member In CType(bsMembers.DataSource, List(Of Member))
sb.AppendLine(Member.ToString)
Next
IO.File.WriteAllText(MembersFile, sb.ToString)
My.Dialogs.InformationDialog("Members have been saved to disk.")
End Sub
End Class
Create a class module and name it member.vb, place the code below in. You will need to tweak the properties as indicated as I did this in VS2010.
Code:
''' <summary>
'''
''' </summary>
''' <remarks>
''' The first property is VS2008 or higher while the remaining properties are
''' VS2010 hence you will need to alter Column2 thru Column8 to the same as Identifier
''' column format for a property.
''' </remarks>
Public Class Member
Private mIdentifier As String
Public Property Identifier As String
Set(ByVal value As String)
mIdentifier = value
End Set
Get
Return mIdentifier
End Get
End Property
Public Property Column2 As String
Public Property Column3 As String
Public Property Column4 As String
Public Property Column5 As String
Public Property Column6 As String
Public Property Column7 As String
Public Property Column8 As String
Public Sub New()
End Sub
Public Overrides Function ToString() As String
Return _
Identifier & "," & _
Column2 & "," & _
Column3 & "," & _
Column4 & "," & _
Column5 & "," & _
Column6 & "," & _
Column7 & "," & _
Column8
End Function
End Class
Create a code module and name it My_Dialogs.vb, place the code below into it.
Code:
Namespace My
<Global.System.ComponentModel.EditorBrowsable(Global.System.ComponentModel.EditorBrowsableState.Never)> _
Partial Friend Class _Dialogs
''' <summary>
''' Ask question with NO as the default button
''' </summary>
''' <param name="Text"></param>
''' <returns></returns>
''' <remarks></remarks>
Public Function Question(ByVal Text As String) As Boolean
Return (MessageBox.Show(Text, My.Application.Info.Title, MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2) = MsgBoxResult.Yes)
End Function
Public Function Question(ByVal Text As String, ByVal Title As String) As Boolean
Return (MessageBox.Show(Text, Title, MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2) = MsgBoxResult.Yes)
End Function
''' <summary>
''' Shows text in dialog with information icon
''' </summary>
''' <param name="Text">Message to display</param>
''' <remarks></remarks>
Public Sub InformationDialog(ByVal Text As String)
MessageBox.Show(Text, My.Application.Info.Title, MessageBoxButtons.OK, MessageBoxIcon.Information)
End Sub
End Class
<Global.Microsoft.VisualBasic.HideModuleName()> _
Friend Module KSG_Dialogs
Private instance As New ThreadSafeObjectProvider(Of _Dialogs)
ReadOnly Property Dialogs() As _Dialogs
Get
Return instance.GetInstance()
End Get
End Property
End Module
End Namespace
Place Members.txt into the same folder as the project executable i.e. Bin\Debug.
Build/run the project. The remove button when depressed will ask for confirmation to remove the current member. Pressing Yes will remove the member from the list but to ensure it is saved you must press the Save button. If you reply No (the default on the confirmation) nothing changes.
