Access variable from another form in Visual Studio with c#

Question

I'm using c# and Visual Studio. I want to access a variable from another form. I've found some things like:

textBox1.Text = form22.textBoxt17.Text;

But I don't want to access a textBox value, I just want to access a variable. I've tried this:

string myVar1 = Form2.myVar2;

But that doesn't work.

Any help?

Update This is what I've got now:

        private string _firstName = string.Empty;
        public string firstName
        {
            get
            {
                return _firstName ;
            }
            set
            {
                if (_firstName != value)
                    _firstName = value;
            }
        }

In formLogin (where the variable is located), just below public partial class formLogin : Form

Then, later in code, inside button on click event:

            OleDbCommand command2 = new OleDbCommand();
            command2.Connection = connection;
            command2.CommandText = "select firstName from logindb where username = '" + txtUsername.Text + "' and password = '" + txtPassword.Text + "'";
            firstName = command2.ExecuteScalar().ToString();

I write this in formAntonyms (from where I want to access the variable) in formLoad event:

        formLogin fli = new formLogin();
        lblName.Text = fli.firstName;            

The problem with all this is that, when formAntonyms opens, lblName is still empty, instead of showing the users name. What am I doing wrong, I've done all the steps right...

Solution

You are on the right path, you should not expose controls or variables directly to client code.

Create a read only property in the form/class you want to read the value from:

//Form2.cs
public string MyVar{get{ return textBoxt17.Text;}}

Then, being form22 the instance variable of your already loaded Form2 form class. Then, from any client code that has a reference to it, you can read the value of the property:

string myVal = frm22.MyVar;

EDIT:

Ok based in your last comment, you have a variable in Florm1 and want to access it from Form2, the principle is the same as the previous example, but instead of exposing a control property you now expose a private variable, and instead of living in Form2 it now lives in Form1:

//Form1.cs
private string _myVar = string.Empty

public string MyVar
 {
    get
    { 
       return _myVar ;
    }
    set
    { 
       if(_myVar != value)
           _myVar = value;
    }
 }

The property is now read/write so you can update its value from client code

//From From2, assuming you have an instance of Form1 named form1:
string val = form1.MyVar;
...
form1.MyVar = "any";