How do you return a string message from a method without the use of exceptions-CodePudding

class Device
{
public void AssignDevice(string playerName)
        {
            if (IsAssigned())
            {
                string message = "This device is already assinged to a player";
                MessageBox.Show(message);
            }
            else
            {
                this.playerName = playerName;
            }
        }
}

im trying to make a method that returns a string in a messageBox if it is true without the use of exceptions. is there any suggestions? this is made in winforms.

CodePudding user response：

As far as I'm concerned you should be able to get the response without working with Exceptions.

MessageBox.Show(message);    
if (result == System.Windows.Forms.DialogResult.Yes)
{
    // Closes the parent form.
    this.Close();
}

Or just check out the microsoft documentation

CodePudding user response：

Technically, you can just return some string, e.g. either error message or null when operation succeeds:

// return error message or null on success
public string AssignDevice(string playerName) {
   if (IsAssigned()) {
     string message = "This device is already assigned to a player";
     
     MessageBox.Show(message);

     return message; 
   }
   else
     this.playerName = playerName;
   
   return message;
}

Or using Try pattern:

// return true on success, false of error, message - error message  
public bool TryAssignDevice(string playerName, out string message) {
   string message = null;

   if (IsAssigned()) {
     message = "This device is already assigned to a player";

     return false; 
   }
   else
     this.playerName = playerName;
   
   return true;
}

usage

if (!TryAssignDevice(playerName, out var errorMessage)) {
  MessageBox.Show(errorMessage); 
}

The drawback of such approach (no exception but some return value(s)) is that the return can be easily ingored.