C#无法'；找不到路径(登录系统)

所以我的程序运行得很好，但每当我在Form 2上注册时，它都说找不到路径。我不知道出了什么问题，请帮我稍后传递，我不知道是否需要在C:上创建一个新文件夹来获取LOGIN.ID

{公共分部类Form1:Form{公共字符串用户名、密码；公共窗体1（）{InitializeComponent（）；}

    private void button2_Click(object sender, EventArgs e)
    {
        Form2 form2 = new Form2();
        form2.Show();
    }
    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            var sr = new System.IO.StreamReader("C''" + textBox1.Text + "''login.ID");
            username = sr.ReadLine();
            password = sr.ReadLine();
            sr.Close();
            if (username == textBox1.Text && password == textBox2.Text)
                  MessageBox.Show("Log-in Successfull", "Success!");
            else
                 MessageBox.Show("Username or password is wrong! ","Error!");
        }
        catch (System.IO.DirectoryNotFoundException )
        {
            MessageBox.Show("The user doesn't exist!", "Error!");
        }
    }
}

}

//形式2

public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();
    }
    private void button2_Click(object sender, EventArgs e)
    {
        Form2 form2 = new Form2();
        form2.Hide();
    }
    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            var sw = new System.IO.StreamWriter ("C''" + textBox1.Text + "''login.ID"); 
            sw.Write(textBox1.Text + "'n" + textBox2.Text);
            sw.Close();
        }
        catch(System.IO.DriveNotFoundException )
        {
            System.IO.Directory.CreateDirectory("C:''" + textBox1.Text);
            var sw = new System.IO.StreamWriter("C''" + textBox1.Text + "''login.ID");
            sw.Write(textBox1.Text + "'n" + textBox2.Text);
            sw.Close();
        }

    }
}

}

var sw = new System.IO.StreamWriter("C''" + textBox1.Text + "''login.ID");

var sw = new System.IO.StreamWriter("C:''" + textBox1.Text + "''login.ID");