How to use variables between unit tests? c# webdriver

Im begginer in webdriver and c#. I want to use variable, from first test in another tests, how do I do that? I got to this point with some examples, but it does not work. I see that first test gets the login right, but when I start the second test and try to sendkeys, I get that loginName is null.

[TestFixture]
public class TestClass
{
    private IWebDriver driver;
    private StringBuilder verificationErrors;
    private string baseURL;
    private bool acceptNextAlert = true;
    static public String loginName;
    static public String loginPassword;

    [SetUp]
    public void SetupTest()...

    [TearDown]
    public void TeardownTest()...

    [Test]
    public void GetLoginAndPassword()
    {
        loginName = driver.FindElement(By.XPath("...")).Text;
        loginPassword = driver.FindElement(By.XPath("...")).Text;
        Console.WriteLine(loginName);
    }
    [Test]
    public void Test1()
    {
        driver.FindElement(By.Id("UserNameOrEmail")).SendKeys(loginName);
        driver.FindElement(By.Id("Password")).SendKeys(loginPassword);
    }