Hi. I have this code that I am trying to make it work but everytime I debug it it always highlight my write record to file stream under the Add button. I've been working on this for how many days and still can't make it work. Please your help is very much appreciated. This code will allow user to read a file and display the contents on the form using the read button and let the user enter the data for eact textboxes. I know I did everything correct as far as getting the data but still doesn't work. Please help! Thanks a lot.
VB.NET:
Imports System.IO
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization
Public Class Form1
Private fileWriter As StreamWriter 'writes data to text file
Private output As FileStream 'maintains connection to file
Private input As FileStream
Private fileReader As StreamReader
'event handler for Save Button
Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
'create dialog box enabling user to save file
Dim fileChooser As New SaveFileDialog()
Dim result As DialogResult = fileChooser.ShowDialog()
Dim fileName As String 'name of file to save data
fileChooser.CheckFileExists = False 'allow user to create file
'exit event handler if user clicked "Cancel"
If result = Windows.Forms.DialogResult.Cancel Then
Return
End If
fileName = fileChooser.FileName 'get specified filename
'show error if user specified invalid file
If fileName = "" Or fileName Is Nothing Then
MessageBox.Show("Invalid File Name", "Error", _
MessageBoxButtons.OK, MessageBoxIcon.Error)
Else
'save file via FileStream if user specified valid file
Try
'open file with write access
output = New FileStream(fileName, FileMode.OpenOrCreate, _
FileAccess.Write)
'sets file to where data is written
fileWriter = New StreamWriter(output)
'disable Save button and enable Add button
btnSave.Enabled = False
btnExit.Enabled = False
btnRead.Enabled = False
btnAdd.Enabled = True
'handle exception if there is a problem opening the file
Catch ex As IOException
'notify user if file does not exist
MessageBox.Show("Error opening file", "Error", _
MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End If
End Sub
'event handler for Add button
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'store Textbox values string away
Dim values As String() = GetTextBoxValues()
'record containing TextBox values to serialize
Dim record As New Record()
'store textbox field in record
'determine whether Textbox ID field is empty
If values(TextBoxIndices.ID) <> "" Then
'store TextB ox values in record and serialize record
Try
'get ID number value from Textbox
Dim IDNumber As Integer = _
Int32.Parse(values(TextBoxIndices.ID))
'determine whether IDNumber is valid
If IDNumber > 0 Then
'store Textbox field in record
record.ID = IDNumber
record.FirstName = values(TextBoxIndices.FIRST)
record.LastName = values(TextBoxIndices.LAST)
record.ClassName = values(TextBoxIndices.CLASSNAME)
record.Grade = values(TextBoxIndices.GRADE)
'write record to file stream
fileWriter.WriteLine(record.ID & "," & record.FirstName & "," & _
record.LastName & vbTab & record.ClassName & vbTab & record.Grade)
Else
'notify user if invalid ID Number
MessageBox.Show("Invalid ID Number", "Error", _
MessageBoxButtons.OK, MessageBoxIcon.Error)
End If
'notify user if error occurs in serialization
Catch ex As IOException
MessageBox.Show("Error Writing to File", "Error", _
MessageBoxButtons.OK, MessageBoxIcon.Error)
'notify user if error occurs regarding parameter format
Catch ex As FormatException
MessageBox.Show("invalid Format", "Error", _
MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End If
ClearTextBoxes() ' clear textbox values
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
txtDisplay.Text = "ID" & vbTab & "Name" & vbTab & "Grade" & vbTab & "Class"
Dim fileChooser As New OpenFileDialog()
Dim result As DialogResult = fileChooser.ShowDialog()
Dim fileName As String
'exit event handler if user clicked the Cancel
If result = Windows.Forms.DialogResult.Cancel Then
Return
End If
fileName = fileChooser.FileName 'get specified file name
ClearTextBoxes()
'show error if user specified invalid file
If fileName = "" Or fileName Is Nothing Then
MessageBox.Show("Invalid File Number", "Error", _
MessageBoxButtons.OK, MessageBoxIcon.Error)
Else
'create FileStream to obtain read access to file
input = New FileStream(fileName, FileMode.Open, FileAccess.Read)
'set file from where data is read
fileReader = New StreamReader(input)
End If
End Sub
Protected TextBoxCount As Integer = 5
'enumeration constants specify Textbox indices
Public Enum TextBoxIndices
ID
FIRST
LAST
CLASSNAME
GRADE
End Enum
'clear all textboxes
Public Sub ClearTextBoxes()
'iterate through every Control on form
For i As Integer = 0 To Controls.Count - 1
Dim myControl As Control = Controls(i) 'get control
'determine whether COntrol is TextBox
If TypeOf myControl Is TextBox Then
'clear Text property (set to empty sting)
myControl.Text = ""
End If
Next i
End Sub
'set text box values to string array values
Public Sub SetTextBoxValues(ByVal values() As String)
'determine whether string array has correct length
If values.Length <> TextBoxCount Then
'throw exception if not correct length
Throw New ArgumentException("There must be " & (TextBoxCount + 1) & _
" strings in the array")
'set array values if array has correct length
Else
'set array values to text box values
txtID.Text = values(Convert.ToInt32(TextBoxIndices.ID))
txtFirstName.Text = values(Convert.ToInt32(TextBoxIndices.FIRST))
txtLastName.Text = values(Convert.ToInt32(TextBoxIndices.LAST))
txtClassName.Text = values(Convert.ToInt32(TextBoxIndices.CLASSNAME))
txtGrades.Text = values(Convert.ToInt32(TextBoxIndices.GRADE))
End If
End Sub
'return text box values as string array
Public Function GetTextBoxValues() As String()
Dim values(TextBoxCount) As String
'copy text box fields to string array
values(Convert.ToInt32(TextBoxIndices.ID)) = txtID.Text
values(Convert.ToInt32(TextBoxIndices.FIRST)) = txtFirstName.Text
values(Convert.ToInt32(TextBoxIndices.LAST)) = txtLastName.Text
values(Convert.ToInt32(TextBoxIndices.CLASSNAME)) = txtClassName.Text
values(Convert.ToInt32(TextBoxIndices.GRADE)) = txtGrades.Text
Return values
End Function
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
'determine whether file exists
If output IsNot Nothing Then
Try
fileWriter.Close() 'close StreamWriter
output.Close() 'close file
'notify user of error closing file
Catch ex As IOException
MessageBox.Show("Cannot close file", "Error", _
MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End If
Application.Exit()
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
End Class
