Передать значения из одного события в другое

        private void button1_Click(object sender, EventArgs e) { Foo1(); }
        private void button2_Click(object sender, EventArgs e) { }
 
        void Foo1() { (a + b) * с }
        void Foo2() { }

public class Test
{
private int a;
public int A {get {return a;}}
 
public void A1(int c) { a = a + c; }
public void A2(int c) { a = a - c; }
}
private Test test = new Test();
private void button1_Click(object sender, EventArgs e) { test.A1(); }
        private void button2_Click(object sender, EventArgs e) { test.A2(); }

public void A1(int c) { a = a + c; }

public class MyClass
{
     public double a { get; set; }
     public double b { get; set; }
     public double c { get; set; }
}

private void Textbox1_Textchanged{object sender, EventArgs e)
{
       myClassInstance.b = Convert.ToDouble((sender as TextBox).Text);
}
private void Textbox2_Textchanged{object sender, EventArgs e)
{
       myClassInstance.c = Convert.ToDouble((sender as TextBox).Text);
}

//MyClass.cs
public void Calculate()
{
      a = b + c;
}

private void Button_Click(object sender, EventArgs e)
{
     myClassInstance.Calculate();
 
     resultTextBox.Text = myClassInstance.a;
}