I cant enable my controls in formmain when i logined

[huelee]

//in form login 
public partial class frmLogin : Form
    {
        private FormMain _frm;
        public frmLogin(FormMain frm)
        {
            InitializeComponent();
            _frm = frm;
        }

	 private void btnLogin_Click(object sender, EventArgs e)
        {
	
	bool CurrentLogin = false;
                CurrentLogin = Login(txtUserName.Text, txtPassword.Text);
                if (CurrentLogin == true)
                {
			//((FormMain)MdiParent).tsOPDIPD.Enabled = true;
			_frm.Controls["tsOPDIPD"].Enabled = true;
			this.hide();
		}
	}
}


//in form Main
public partial class FormMain : Form
    {
        public FormMain()
        {
            InitializeComponent();
        }

 	private void FormMain_Load(object sender, EventArgs e)

        {
		tsOPDIPD.Enabled = false;

		frmLogin frm = new frmLogin(this);
            	frm.ShowDialog();
            	frm.MdiParent = this;
	}
}

Error on "_frm.Contr ols["tsOPDIPD"].Enabled = true;" like this: Object reference not set to an instance of an object.

Please help me.

[Aimee Bailey]

Maybe this will help:

private void btnLogin_Click(object sender, EventArgs e)
{
    if(_frm == null)
    {
        MessageBox.Show("Variable _frm was never set.");
    }

    if(Login(txtUserName.Text, txtPassword.Text))
    {
        _frm.tsOPDIPD.Enabled = true;
        this.hide();
    }
}

The error you received usually means that either _frm or _frm.Controls["tsOPDIPD"] does not exist, when I rely on a variables being set like that, I find it useful to add a bit of error checking before I use them.

Also note, that you could also validate to see weather tsOPDIPD exists within the Controls collection by using the following:

if(_frm.Controns.ContainsKey("tsOPDIPD"))
{
    // stuff if the control key exists
}

All the best.

Aimee