IOException Was Unhandled Error Help for Newbie - visual-studio-2010

Question

You'll have to excuse me for a repeat question but I just can't seem to understand the responses others have been posting. My coding skills are very limited (barely a year in vb 2006 and vs 2010)
I know that the sr has opened too many of the same file but I cant figure out a fix for it. Explaining it to me in simple concepts would be very helpful. Once again sorry for the newby-ness.
Project Explanation: Create a bowling league stats keeper. cmdRegisterBowler adds bowler name to a dat file (bowlers.dat). cmdEnterScores will write name and stats to games.dat file.
Private Sub cmdRegisterBowler_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRegisterBowler.Click
'BOWLER REGISTRATION
Dim Person As String
Dim Team As String
txtName.Text.ToUpper()
txtTeam.Text.ToUpper()
Person = txtName.Text
Team = txtTeam.Text
If Person <> "" And Team <> "" Then
If IsInFile(Person & " " & Team) = True Then
MessageBox.Show(Person & " is already in the file.", "Error")
txtName.Clear()
txtTeam.Clear()
txtName.Focus()
Else
'swb = stream writer bowlers file
Dim swb As IO.StreamWriter = IO.File.AppendText("bowlers.dat")
swb.WriteLine(Person & " " & Team)
swb.Close()
MessageBox.Show(Person & " has been added to the file.", "Information Added")
txtName.Clear()
txtTeam.Clear()
txtName.Focus()
End If
Else
MessageBox.Show("You must enter a name.", "Information Incomplete")
End If
End Sub
Function IsInFile(ByVal person As String) As String
If IO.File.Exists("bowlers.dat") Then
Dim sr As IO.StreamReader = IO.File.OpenText("bowlers.dat")
Dim individual As String
Do Until sr.EndOfStream
individual = sr.ReadLine
If individual = person Then
Return True
sr.Close()
End If
Loop
sr.Close()
End If
Return False
End Function
Private Sub cmdEnterScores_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdEnterScores.Click
'SCORE ENTRY
Dim Person As String
Dim Team As String
Dim Score1 As Double
Dim Score2 As Double
Dim Score3 As Double
Dim Average As Double
Dim Display As String = "{0,-10} {1,10} {2,20} {3,10} {4,10} {5,10} {6,10}"
Dim Total As Double
Person = txtName2.Text
Team = txtTeam2.Text
Score1 = Val(txtFirstGame.Text)
Score2 = Val(txtSecondGame.Text)
Score3 = Val(txtThirdGame.Text)
Total = Score1 + Score2 + Score3
Average = Total / 3
Dim swb As IO.StreamWriter = IO.File.AppendText("bowlers.dat")
'Checks for blank entries
If Person <> "" Then
'Checks to see if person is registered
If IsNotInFile(Person) Then
Dim Response As Integer
' Displays a message box with the yes and no options to register bowler.
Response = MsgBox(Prompt:="The bowler you have entered is currently not registered. Would you like to do so?", Buttons:=vbYesNo)
'Yes button was selected. Bowler is then registered to bowlers.dat
If Response = vbYes Then
''swb = stream writer bowlers file
swb.WriteLine(Person & " " & Team)
swb.Close()
MessageBox.Show(Person & " has been added to the file.", "Information Added")
'The no button was selected. Focus is set to bowler registration group box
Else : Response = vbNo
txtName2.Clear()
txtTeam2.Clear()
txtFirstGame.Clear()
txtSecondGame.Clear()
txtThirdGame.Clear()
txtName.Focus()
End If
'If no then clears score entry group box and sets focus back to bowler registr
txtName.Clear()
txtName.Focus()
Else
'Write scores to games.dat file
'swg = stream writer games file
Dim swg As IO.StreamWriter = IO.File.AppendText("games.dat")
swg.WriteLine(Name & " " & Team & " " & Score1 & " " & Score2 & " " & Score3)
swg.Close()
MessageBox.Show(Person & "'s stats added to the file.", "Information Added")
txtName.Clear()
txtName.Focus()
Dim Display2 As String = "{0,-10} {1,10} {2,20} {3,10} {4,10} {5,10} {6,10}"
lstDisplay.Items.Add(String.Format(Display2, Person, Team, Score1, Score2, Score3, Total, Average))
End If
Else
MessageBox.Show("You must enter a name.", "Information Incomplete")
End If
End Sub
Function IsNotInFile(ByVal person As String) As String
If IO.File.Exists("bowlers.dat") Then
Dim sr As IO.StreamReader = IO.File.OpenText("bowlers.dat")
Dim individual As String
Do Until sr.EndOfStream
individual = sr.ReadLine
If individual <> person Then
Return True
sr.Close()
End If
Loop
sr.Close()
End If
Return False
End Function
Heres all my code. Thanks for any help in advance.

Answer 1

I haven't used Visual Basic in quite a while, but I believe the solution is simple.
Basically, your interactions with the System.IO library are currently very optimistic. You should always wrap IO interactions within a TRY...CATCH...END TRY block.
Check it out here: MSDN Example of StreamReader.ReadLine
To illustrate more clearly my meaning, I've altered one of your functions here:
Function IsInFile(ByVal person As String) As String
Try
If IO.File.Exists("bowlers.dat") Then
Dim sr As IO.StreamReader = IO.File.OpenText("bowlers.dat")
Dim individual As String
Do Until sr.EndOfStream
individual = sr.ReadLine
If individual = person Then
Return True
sr.Close()
End If
Loop
sr.Close()
End If
Return False
Catch ie as IOException
MessageBox.Show("Failed to search for " & person & " in file.", "Error")
Return false
End Try
End Function
I'd apply similar logic to surround all your interactions with Files within your code. I'd also recommend against using MessageBox to report errors -- it's okay for small projects, but for anything larger you're going to want to look up using a logging framework. Or build a debug console into your application that you can selective turn on or off via configuration.