title: string input from textbox if/else
body: <p>I am trying to use the input from a textbox as a string. The issue is that I need
  it to only use it if the box is populated. My goal is to allow a user to input a username in the box, if the box is empty I would like it to still use my global static string if possible.
  If any better ideas I am up for them</p>
  
  <p>My program uses the USERNAME variable to get the username but I would like the option for the user to be able to enter username in box if they need.</p>
  
  <pre><code>string username = (Environment.GetEnvironmentVariable("USERNAME")); 
  </code></pre>
  
  <p>thankyou</p>
  
  <pre><code>public partial class Form1 : Form
      {
  
  //My original strings, This is what i need to fix
  
         static string config = File.ReadAllText("config.ini");
         static string username = (Environment.GetEnvironmentVariable("USERNAME"));
         static string Backups = config + @"\" + username + @"\" + "Backups" + @"\";
         static string items;
  
          public Form1()
          {
              InitializeComponent();
  
          }
  
  // How would i re purpose the string depending on the if?
    if (!String.IsNullOrEmpty(toolStripTextBox1.Text))
              {
                  toolStripTextBox1.Text = username;
                  MessageBox.Show(username);
  
              }
              else
              {
                  string username = (Environment.GetEnvironmentVariable("USERNAME"));
  
              }
  </code></pre>