在c＃中生成唯一ID

Question

I tried to generate a unique ID starting from 1 but the number stays the same.. I'm trying to use session variable so it can go like 1,2,3,4...

Main page:

protected void calculateButton_Click(object sender, EventArgs e)
{
 int bookingID = 0;
    bookingID += 1;
    bookingIDTextBox.Text = bookingID.ToString();
}
protected void confirmButton_Click(object sender, EventArgs e) 
{
    Session["confirmBooking"] = "confirm";
    Session["bookingID"] = bookingIDTextBox.Text;
    Response.Redirect("MainBookingForm.aspx");
}

Second page:

protected void newBookingButton_Click(object sender, EventArgs e)
{
    string bookingRef = (string)(Session["bookingID"]);
    Session["bookingRef"] = bookingRef;
    Response.Redirect("BookingForm.aspx");
}

Answer 1

You are declaring the variable each time you press the button, so it will always be 1

Declare the variable outside the method

int bookingID = 0;
protected void calculateButton_Click(object sender, EventArgs e)
{ 
    bookingID += 1; // You can also use bookingID++
    bookingIDTextBox.Text = bookingID.ToString();
}

EDIT note that it will be reset when you restart the application, you might want to store it somewhere (application settings / database etc)

Answer 2

you can use the Application object - it is part of the HttpContext and is directly accessible on any page.

If you don't want to use it, you may want to write a Globals class (or whatever name you like) that holds static members.

public class Globals
{
  public static int Counter { get; set;}
}

// accessed from other classes:
Globals.Counter++;