c＃Groupbox属性更改

Question

I have a Groupbox on a windows form with the enabled property set to false. I want to enable the Groupbox in code after verifying a username and password. Whe I call the Groupbox.Enabled = true method the state of the Groupbox does not change. I am calling from another windows form and I have instantiated the form prior to making the call to enable the Groupbox. Am I missing something?

namespace ShadowKey
{
    public partial class SetKey : Form
    {
        ConfigOptions cOptions = new ConfigOptions();

        public SetKey()
        {
            InitializeComponent();
        }

        private bool CompareStrings(string string1, string string2)
        {
            return string.Compare(string1, string2, true,     System.Globalization.CultureInfo.InvariantCulture) == 0 ? true : false;
    }

    private void btnOk_Click(object sender, EventArgs e)
    {
        try
        {
            Thread.Sleep(2000);
            string connection = @"Data Source=|DataDirectory|\EncrypterDB.sdf";
            SqlCeConnection dataCon = new SqlCeConnection(connection);
            dataCon.Open();
            string userText = tbUser.Text;
            string pwrdText = tbPwrd.Text;
            SqlCeCommand cmd = new SqlCeCommand("Select usr_name, usr_password FROM user_accounts WHERE usr_name='" + tbUser.Text + "' and usr_password='" + tbPwrd.Text + "'", dataCon);
            cmd.Parameters.Add(new SqlCeParameter("username", userText));
            cmd.Parameters.Add(new SqlCeParameter("password", pwrdText));

            SqlCeDataReader rdr = cmd.ExecuteReader();

            try
            {
                rdr.Read();
                if (rdr["usr_name"].ToString().Trim() == userText && rdr["usr_password"].ToString().Trim() == pwrdText)
                {
                    cOptions.gbEncryptionKey.Enabled = true;
                }
            }
            catch
            {
                MessageBox.Show("Invalid Username or Password!", "Login Error!");
            }
            rdr.Close();
            dataCon.Close();
        }

        catch
        {
            MessageBox.Show("You've thrown an exception!", "Error!");
        }

    }
}

}

Answer 1

There is not a lot of code to go by but I will venture a guess. I suspect your LinkLabel is creating a new instance of ConfigOptions. Then, when the Enabled property is set to true it is being set on the instance that was created when SetKey was instantiated. This means that you are not updating the one that is being shown, but another one that is hidden. Put a breakpoint in the ConfigOptions constructor and see if it is being called more than once.

Answer 2

I don't see when ConfigOptions gets displayed, but lets say it is displayed as the first form to open and you are now viewing the second form. The way to access a property on ConfigOptions would be:

(Application.OpenForms[0] as ConfigOptions).ThePropertyToSet = PropertyValueHere;

Basically, you want to access the forms through Application.OpenForms based on the index(order) in which they were opened. Doing the following does nothing, because you are not actually setting the property on the open ConfigOption form.

ConfigOptions cOptions = new ConfigOptions();
cOptions.gbEncryptionKey.Enabled = true;