Reading a serialized file.

18y3kVisual Basic .NET

Basically, I have 5 textboxs where I enter information to be serialized to a text file. I wan't to display all the contents from the text file into a multiline textbox, this is where my problem occurs.

I can only read the first 'record' of the text file, nothing else gets displayed in the textbox. The only way im able to get everything is by creating an endless loop and catching a serialization exception when it gets to the end, which breaks the loop.

Basically, What is the proper way of doing this?

BinaryFormatter read = new BinaryFormatter();

FileStream file;

file = new FileStream(openFile.FileName, FileMode.Open, FileAccess.Read);

try

{

for (int i = 0; i < 2; i++)

{

Student student = (Student)read.Deserialize(file);

txtDisplay.Text += " " + student.LastName.ToString() + ",";

txtDisplay.Text += " " + student.FirstName.ToString() + ": ";

txtDisplay.Text += " " + student.ID.ToString();

txtDisplay.Text += " " + student.Class.ToString();

txtDisplay.Text += " " + student.Grade.ToString() + "\r\n";

i--;

}

catch (SerializationException)

{

}

This can't be the best way...

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

r18y ago
Ok, guess ill show a little more here.

[ Serializable ]

public class Student

{

private string _firstName;

private string _lastName;

private string _ID;

private string _class;

private string _grade;

public Student(string first, string last, string id, string program, string grade)

{

FirstName = first;

LastName = last;

ID = id;

Class = program;

Grade = grade;

}

public string FirstName

{

get { return _firstName; }

set { _firstName = value; }

}

gonna leave out the rest of the public properties, nothing special with them.

and here is when I write to the file.

FileStream file;                                                                                     BinaryFormatter formatter = new BinaryFormatter();

SaveFileDialog save = new SaveFileDialog();                                                      DialogResult save1 = save.ShowDialog();                                                                file = new FileStream(save.FileName, FileMode.Append, FileAccess.Write);

Student student = new Student(txtFirst.Text, txtLast.Text,txtID.Text,txtClass.Text,txtGrade.Text);

try                                                                                                                                     {                                                                                                          formatter.Serialize(file, student);

}

catch (SerializationException)

{

MessageBox.Show("error");

}

file.Close();

So im a little confused when you say to serialize the Student object instead of student. Serializing the Student object itself would get all the individual student properties? kind of confusing here lol, probably should have a better naming convention here. Anyways how do i go about doing that?
Scott Lysle18y ago
I can't see what you are serializing but I am thinking that is where the trouble is; are you just putting a series of the student objects into this file? Right off hand, since you want this file to contain a collection of students you should have a Students class that is marked as serializble alone with your Student class which is also serializable. The Students class should maintain a collection of Student objects in a hashtable or sortedlist. When you add a new student, you would create an instance of that student and then add it to the collection in the Students class. When you serialize and deserialize, you should be doing that to the Students object rather than an individual Student object. When you deserialize, you can convert the collection back to the collection type (say a sortedlist) and then iterate through the values contained in the sortedlist (casting each value to a Student object) and then you can recover the values from that object for display in your application.