Question

I know that when you use a static variable it’s value is shared across all users.

static string testValue = "";
protected void SomeMethod(object sender, EventArgs e)
{
    testValue = TextBox1.Text;        
    string value = TestClass.returnString(TextBox1.Text); // <-- return from a static method
}

So in this case, if one user goes to a website and puts a value into the textbox, the string testValue will be overwritten by another value when another user enters something in the textbox. (I think?)

I now have this class:

public class TestClass
{
  public static string returnString(string msg)
  {
    return msg;
  }
}

My question is: if I use a static method, is the return value of that method shared for all users as well? or is that always a “unique” value per user?

Let’s say that this method is called five times, by five different users, will this static method return the value a particular user has entered, or is it possible that one user gets a value that another user entered?

Answer 1

Your question was:

my question now is, if i use a static method, is the return value of
that method shared for all users aswell? or is that always a “unique”
value per user ?

And the answer is, it depends. Using your example:

public class TestClass 
{ 
  public static string returnString(string msg) 
  { 
    return msg; 
  } 
}

In this case, 5 different users would (most likely) pass in 5 different strings to the static method. Therefore they would get back five differents strings. So for this case:

string value = TestClass.returnString(TextBox1.Text);

each user would get back whatever they had typed into their own TextBox. If, on the other hand the code was this:

string value = TestClass.returnString(testValue);

They would all get back what happened to be in the static string at the time of the return.

So the rule to keep in mind is:

• If the method uses static member variables, there is a risk of different users affecting each other’s results. This is true regradless of whether the method is static or not.
• If the method uses only call parameters and local variables, and the call parameters are not themselves pointing to statisc member variables, calls from different users will not affect each other.