Controlling a button from another form c#

Question

I have this project where you can login as a user and as an employee and if you log in as an employee certain buttons such as reports will show up on the homepage.

I have two forms named HomePage and frmSignIn. If the user signs in from frmSignIn I want certain button on HomePage to be visible. I have tried several ways but cannot get it to work.

I did make the button public to see if it works, although I know this is bad practice.

if (ValidCredentials(txtUsername.Text, txtPassword.Text) == true && checkBoxEmployee.Checked == true && txtBoxEmpPin.Text.Equals(employeePin))
{
    this.DialogResult = DialogResult.OK;
    this.Tag = _usersId;
    this.Close();
    MessageBox.Show("You have successfully logged in as an employee.");

    HomePage hp = new HomePage();

    hp.Button.Visible = true;   // !!!! Does not work !!!!
}

It seems you want role based security, you can use global variables/class for same. http://stackoverflow.com/questions/1293926/c-sharp-winforms-global-variables — Thakur, Nov 29 '16 at 07:01
`hp` is another instance of the Home page, it is entirely different from the actual homepage — sujith karivelil, Nov 29 '16 at 07:01
Thank you for the reply. How would I go about changing it then? — Mallory Rich, Nov 29 '16 at 07:03
wish form is the parent form? I mean which from calling the another form. you can send the parent from as parameter to the child form. — Bakri, Nov 29 '16 at 07:03
Are you sure it is `HomePage` and not `frmHomePage` as you described in question? — Prajwal, Nov 29 '16 at 07:03
your instantiation of HomePage is after the form close, which looks not correct. if you wish to close current form and then initialize the next, you can do so in your formClosed event — Rex, Nov 29 '16 at 07:08

score 1 · Answer 1 · answered Nov 29 '16 at 07:17

One way to do this, is making your original homepage known to the frmSignIn.

To do this, you could create a property in your frmSignIn like

public MyHomePage Form { get; set; }

Then, when creating the SignIn form, also add the reference of the homepage to the new instance of frmSignIn. Something like:

var mySignInForm = new frmSignIn();
mySignInForm.MyHomePage = this;

Now, you have a decent reference in your frmSignIn to do whatever you want. You still would have to make the button public though.

Alternatively you could, instead of the complete form, just add a reference to the button you need in the same way.

This may not be the prettiest and most elegant solution, but it will work.

score 1 · Answer 2 · answered Nov 29 '16 at 07:24

You can use public property where You keep reference to your button, try this example.

Form1

public partial class Form1 : Form
{



    public Form1()
    {
        InitializeComponent();

    }

    private void button1_Click(object sender, EventArgs e)
    {
        Form2 x = new Form2();
        x.Button1 = this.button1;
        x.Show();
    }
}

Form2

public partial class Form2 : Form
    {
        private Button _button1;

        public Button Button1
        {
            get { return _button1; }
            set { _button1 = value; }
        }

        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            _button1.Visible = false;
        }
    }

score 0 · Accepted Answer · answered Nov 29 '16 at 07:10

0

Create a method for homepage which enables Button

public void EnableButton(){
   this.Button.Visible = true;
}

And Do this,

this.DialogResult = DialogResult.OK;
this.Tag = _usersId;
HomePage hp = new HomePage();  //here, creating instance of homepage
hp.EnableButton(); //This enables the required button
MessageBox.Show("You have successfully logged in as an employee.");
hp.showDialog(); //Shows HomePage
this.Hide(); //Hides login page.

answered Nov 29 '16 at 07:10

Prajwal

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This works but it opens another HomePage form which makes me have 2 up when I log in. I have an initial one that is up when logging in and the signin form pops up as a modal form but the first HomePage is never closed. – Mallory Rich Nov 29 '16 at 07:20
Yes so when I run the program there's a homepage screen that opens up. From this home page I can log in and the frmSignIn form opens. However, the homepage never closes so when I try your method it just opens another homepage. – Mallory Rich Nov 29 '16 at 07:26
Then don't create new instance. remove this --> `HomePage hp = new HomePage();` Also, where is the reference to that homepage instance? – Prajwal Nov 29 '16 at 07:30
Just call `EnableButton()` for that instance. It should work. And revert `button` to private. – Prajwal Nov 29 '16 at 07:32
No no i'm sorry. Maybe i'm not explaining this clearly. The program starts with the homepage. The homepage has a button called Sign In which opens frmSignIn but never closes the initial homepage form. If I sign in as an employee through frmSignIn I want the 'button' to be visible. – Mallory Rich Nov 29 '16 at 08:05

Controlling a button from another form c#

3 Answers3