please help, changing the value problem

[asem0525]

Hello guys, I have this kind of problem:
first, the textBox tbISBN has a value that is read from the text file, but then after pressing the "Clear" button, it should be realized, and when I enter the new text into the textBox it should get the new text that I entered, but it keeps it's first value, even after the "Clear" button event.
Here is the code.

public partial class _Default : System.Web.UI.Page 
{
   private Book selectedBook;
   public string strISBN;
   public string strCurrent;
   public string[] strFields;
   public char[] chrDelimiter = { ',' };
   public SortedList slBook;
   public StreamReader srdCurrent;
 
    public string content;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            SortedList slBooks = new SortedList();
 
            StreamReader srdCurrent = new StreamReader(Request.MapPath(@"App_Data\Books.txt"));
 
            strCurrent = srdCurrent.ReadLine();
 
            while (strCurrent != null)
            {
                Book recNew = new Book();
                strFields = strCurrent.Split(chrDelimiter);
 
                recNew.Title = strFields[0];
                recNew.ISBN = strFields[1];
                recNew.Author = strFields[2];
                recNew.Publisher = strFields[3];
                recNew.UnitPrice = System.Convert.ToDecimal(strFields[4]);
 
                slBooks.Add(recNew.Title, recNew);
                strCurrent = srdCurrent.ReadLine();
 
                // Add the book title to the drop down list
                ddlBooks.Items.Add(recNew.Title);
            }
 
            // Close the file when reading is complete.
            srdCurrent.Close();
 
            // Add the sorted list to this session 
            Session.Add("Book", slBooks);
 
        }
 
        selectedBook = GetSelectedBook();
        if (selectedBook != null)
        {
           tbTitle.Text = selectedBook.Title;
            tbISBN.Text = selectedBook.ISBN;
            tbAuthor.Text = selectedBook.Author;
            tbPublisher.Text = selectedBook.Publisher;
            tbPrice.Text = selectedBook.UnitPrice.ToString("c");
            imgBook.ImageUrl = "Images/Books/" + selectedBook.ISBN + ".gif";
        }
    }
    private Book GetSelectedBook()
    {
        SortedList slBooks = (SortedList)Session["Book"];
        if (slBooks == null)
            return null;
 
        string strTitle = ddlBooks.SelectedValue;
        return (Book)slBooks[strTitle];
    }
 
 
    //***********************************************************************************
    public void btnClear_Click(object sender, EventArgs e)
    {
        /*selectedBook.Title = "";
        selectedBook.ISBN = "";
        selectedBook.Author = "";
        selectedBook.Publisher = "";
        selectedBook.UnitPrice = 0.00m;*/
        StreamWriter delete = new StreamWriter(Request.MapPath(@"App_Data\Boo.txt"));
 
        tbTitle.Text = "";
        tbISBN.Text = "";
        tbAuthor.Text = "";
        tbPublisher.Text = "";
        tbPrice.Text = "";
        imgBook.ImageUrl = "";
        lblUploadResult.Text = "";
 
    }
    //***********************************************************************************
    protected void AddBook()
    {
        strISBN = tbISBN.Text;
        string filePath = Server.MapPath(@"App_Data\Books.txt");
 
        StreamReader sr = File.OpenText(filePath);
 
        //StreamReader srdCurrent = new StreamReader(Request.MapPath(@"App_Data\Books.txt"));
 
        //StreamWriter rite = new StreamWriter(Request.MapPath(@"App_Data\Boo.txt"));
        //rite.WriteLine("any string");
        //rite.Close();
 
        try
        {
 
            content = sr.ReadToEnd();
            if (content.Contains(strISBN))
            {
                lblUploadResult.Text = "isbn contained";
                sr.Close();
            }
            else
            {
                StreamReader srdCurrent = new StreamReader(Request.MapPath(@"App_Data\Books.txt"));
 
                StreamWriter rite = new StreamWriter(Request.MapPath(@"App_Data\Boo.txt"));
                rite.WriteLine("any string");
                rite.Close();
 
            }
        }
        catch (Exception) { }
 
    }
 
 
 
 
    //**************************************************************************************
 
    protected void btnSave_Click(object sender, EventArgs e)
    {
        AddBook();
    }
 
 
}
 

Thank you very much!

[dorinbogdan]

Try to assign a char array (char[]) to tbISBN.Text instead of a String.
If still not working, please post or attach the required code to run this part of project.