C# WinForms.NET 启用另一个类的控制

Question

在我的程序中，我有两种形式。public partial class Form1 : Form,

和一个登录表格。public partial class Login : Form. 两者都在同一个 namespace

当在主窗口上点击登录按钮时，会打开登录窗口。

public partial class Form1 : Form
{
    private void LoginToolStripMenuItem_Click(object sender, EventArgs e) //Login button event
    {
        LoginWindow = new Login();
        LoginWindow.ShowDialog();
        LogOutToolStripMenuItem.Enabled = true;
    }
}

当输入密码时，我想在主屏幕上为用户启用额外的控件。

groupBox2默认是不可见的，现在我想让它可见。

public partial class Login : Form
{
    public Login()
    {
        InitializeComponent();
    }

    public void button1_Click(object sender, EventArgs e) //Confirm click event
    {
        if (textBox1.Text == Form1.password)  //Here, no trouble accessing a string from the main screen
        {
            Form1.groupBox2.Visible = true; //********** Here is my problem **********
            Form1.LoginWindow.Close();
        }
        else
        {
            textBox1.Text = "Incorrect password";
            textBox1.SelectAll();
        }
    }
}

我如何克服 "An object reference is required for the non-static field, method or property 'Form1.groupBox2' 问题？

我所有的控件都已经设置为public.我看了又看，想不通，现在快把我逼疯了，我不期望有一个现成的解决方案，只希望有一个好的解释。

Answer 1

你可以像这样在你的登录表单中引发一个事件。

public partial class Login : Form
{
  public EventHandler OnPasswordDone; // declare a event handler

  public Login()
  {
      InitializeComponent();
  }

  public void button1_Click(object sender, EventArgs e) 
  {
      if (textBox1.Text == Form1.password)  
      {
          // raise the event to notify main form
          OnPasswordDone(this, new EventArgs());
      }
      else
      {
          textBox1.Text = "Incorrect password";
          textBox1.SelectAll();
      }
  }
}

而在你的主表单中：

public partial class Form1 : Form
{
    private void LoginToolStripMenuItem_Click(object sender, EventArgs e) //Login button event
    {
        LoginWindow = new Login();
        LoginWindow.OnPasswordDone += Login_PasswordDone; // regist your event here
        LoginWindow.ShowDialog();
        LogOutToolStripMenuItem.Enabled = true;
    }

    private void Login_PasswordDone(object sender, EventArgs e)
    {
        //Do what you need to do here like:
        groupBox2.Visible = true;
    }
}

Answer 2

由于Form1不是静态类，所以你应该创建这个类的对象，然后设置可见性为true，如

Form1 formobj=new Form1();
formobj.groupBox2.Visible = true;