Visual Basic Sortierung ein Array mit eingelesenen Daten aus Textdatei

Question

Ich habe Probleme mit diesem:

Die btnDisplay_Click Verfahren sollte die fünf Namen in der Datei enthaltenen states.txt lesen, speichern jeweils in einem fünf- Element eindimensionales Array. Die Prozedur sollte das Array in absteigender Reihenfolge sortieren und dann den Inhalt des Arrays im Listenfeld anzeigen.

Mit meinem Code kann ich die 5 Zustandsnamen in der Listbox anzeigen lassen, sie werden jedoch nicht sortiert.

erste Iteration CODE (alt):

Public Class frmMain 

Private Sub btnDisplay_Click(sender As Object, e As EventArgs) Handles btnDisplay.Click 

    'Declare an array for 5 states 
    Dim strStates(4) As String 

    Dim strStateName As String 

    'Sort the array in descending order 
    Array.Sort(strStates) 
    Array.Reverse(strStates) 

    'Declare variable to hold stream reader object 
    Dim inFile As IO.StreamReader 

    'Check if txt file exists before opening to avoid run time error/crash 
    If IO.File.Exists("states.txt") Then 
     'Open the file 
     inFile = IO.File.OpenText("states.txt") 
     'Loop instructions until end of file is reached 
     Do Until inFile.Peek = -1 
      'Read a line 
      strStateName = inFile.ReadLine 
      'Add line (state) to list box 
      lstNames.Items.Add(strStateName) 
     Loop 
     'Close the file 
     inFile.Close() 
    Else 
     'Show a message box telling user file can't be found 
     MessageBox.Show("File does not exist or cannot be found.", "States", MessageBoxButtons.OK, MessageBoxIcon.Information) 
    End If 
End Sub 

Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click 
    Me.Close() 
End Sub 
End Class 

habe ich versucht, als auch die Sortierlinien innerhalb der Schleife setzt. Wie bekomme ich dies, um das sortierte Array in der Listbox anzuzeigen?

zweite Iteration CODE (aktuellen):

Public Class frmMain 

Private Sub btnDisplay_Click(sender As Object, e As EventArgs) Handles btnDisplay.Click 

    'Declare an array to hold all 5 states 
    Dim strStates(4) As String 

    'Declare variable to hold loop counts 
    Dim i As Integer = 0 

    'Declare variable to hold stream reader object 
    Dim inFile As IO.StreamReader 

    'Check if txt file exists before opening to avoid run time error/crash 
    If IO.File.Exists("states.txt") Then 
     'Open the file 
     inFile = IO.File.OpenText("states.txt") 
     'Loop instructions until end of file is reached 
     Do Until inFile.Peek = -1 
      'Read a line and store in array 
      strStates(i) = inFile.ReadLine 

      'Message box to confirm array loop is working correctly 
      MessageBox.Show(strStates(i)) 

      'Manually increment array counter 
      i = i + 1 
     Loop 

     'Close the file 
     inFile.Close() 

     'Sort the array in descending order 
     Array.Sort(strStates) 
     Array.Reverse(strStates) 

     'Output to list box 
     lstNames.Items.Add(strStates(i)) 'error thrown here 

    Else 
     'Show a message box telling user file can't be found 
     MessageBox.Show("File does not exist or cannot be found.", "States", MessageBoxButtons.OK, MessageBoxIcon.Information) 
    End If 
End Sub 

Answer 1

Aktualisieren Sie die If-Anweisung:

If IO.File.Exists("states.txt") Then 
    'Open the file 
    inFile = IO.File.OpenText("states.txt") 
    'Loop instructions until end of file is reached 
    Do Until inFile.Peek = -1 
     'Read a line and store in array 
     strStates(i) = inFile.ReadLine 

     'Manually increment array counter 
     i = i + 1 
    Loop 

    'Close the file 
    inFile.Close() 

    'Sort the array in descending order (Next 2 lines don't work) 
    Array.Sort(strStates) 
    Array.Reverse(strStates) 

    'Output to list box 
    lstNames.Items.Add(strStates(i)) 

Else 
    'Show a message box telling user file can't be found 
    MessageBox.Show("File does not exist or cannot be found.", "States", MessageBoxButtons.OK, MessageBoxIcon.Information) 
End If 

Answer 2

Ich habe es, dank der Hilfe von zwei! für meine letzte Frage, ich habe gerade hinzugefügt:

 For i = 0 To strStates.Length - 1 
      lstNames.Items.Add(strStates(i)) 
     Next i 

So ist der letzte Arbeits Code wie folgt aussieht:

Public Class frmMain 

Private Sub btnDisplay_Click(sender As Object, e As EventArgs) Handles btnDisplay.Click 

    'Declare an array to hold all 5 states 
    Dim strStates(4) As String 

    'Declare variable to hold loop counts 
    Dim i As Integer = 0 

    'Declare variable to hold stream reader object 
    Dim inFile As IO.StreamReader 

    'Check if txt file exists before opening to avoid run time error/crash 
    If IO.File.Exists("states.txt") Then 
     'Open the file 
     inFile = IO.File.OpenText("states.txt") 
     'Loop instructions until end of file is reached 
     Do Until inFile.Peek = -1 
      'Read a line and store in array 
      strStates(i) = inFile.ReadLine 

      'Message box to confirm array loop is working correctly 
      'MessageBox.Show(strStates(i)) 

      'Manually increment array counter 
      i = i + 1 
     Loop 

     'Close the file 
     inFile.Close() 

     'Sort the array in descending order 
     Array.Sort(strStates) 
     Array.Reverse(strStates) 

     'Output to list box 
     For i = 0 To strStates.Length - 1 
      lstNames.Items.Add(strStates(i)) 
     Next i 

    Else 
     'Show a message box telling user file can't be found 
     MessageBox.Show("File does not exist or cannot be found.", "States", 
     MessageBoxButtons.OK, MessageBoxIcon.Information) 
    End If 
End Sub 

Danke Jungs!