怎么样实现窗体1引用窗体2的变量啊？
代码如下：  【 窗体2：】
     public void buttonItem1_Click(object sender, EventArgs e)
        {
                double R_Na = Convert.ToDouble(W_Na.Text.Trim());
                double R_Ca = Convert.ToDouble(W_Ca.Text.Trim());
         }
           【 窗体1：】

        private void Get_XY()
        {
            float Y_Sum = R_Na / 23 + R_Ca / 20
            float F_Sum = R_Ca / 35.5
         }