Passing Variable from another class into a form

Question

I am struggling with passing a Variable (a string) in C# for a special problem:

Overview:

I am writing a plugin for a purchased program at my company. The program (or better: the programs support) gives the user basic C#-Code which basically just opens a form, and connects the program with whatever I write down in the forms code. As it is a Visual-Studio-Solution I get some files: "MyUserInterface.cs" and "MyUserInterface.Designer.cs".

"MyUserInterface.Designer.cs" defines the look of my form, i thing the most importand parts for my problem are:

partial class MyUserInterface
{   
    [...]     
    private void InitializeComponent()
    {
        [...]
        this.f_status = new System.Windows.Forms.Label();
        this.SuspendLayout();
        [...]
        // 
        // status
        // 
        this.f_status.Name = "status";
        this.f_status.Text = "WELCOME TO MYPLUGIN v2";
        [...]
        this.Controls.Add(this.f_status);
        this.ResumeLayout(false);
        this.PerformLayout();
    }

    [...]
    private System.Windows.Forms.Label f_status;
    [...]
}

The most important code from "MyUserInterface.cs" is:

partial class MyUserInterface
{
    [...]
    public MyUserInterface()
    {
        InitializeComponent();
    }
    [...]
    private void click_compute(object sender, EventArgs e)
    {
        //Basically everythings runs here!
        //The code is opend in other classes and other files
    }
}

Now as i marked in the code section, my whole code runs in the "click-compute" Function and is "outsourced" into other classes.

One important part of my code is found in "statushandler.cs":

class statushandler
{
    [...]
    public static void status_msg(string c_msg)
    {
        [...]
        f_status.Text = c_msg; // And here is my problem!!
        [...]
    }
}

Problem:

In my special case, i try to change the text of the "f_status"-Lable while running my code by using the "status_msg" Function!

While I pass variables between classes a few times in my code. A cannot figure out, why this explicit one cant be found inside "statushandler". (It is no problem as long as I stay inside the original "click_compute", without going into a different class).

What I already tried:

1.) I tried to change basically everything in "MyUserInterface" into "public",

2.) Also I tried to call f_status in status_msg like MyUserInterface.f_status.Text,

3.) Write a Getter/Setter-Function in "MyUserInterface.(Designer.)cs" (both), which was catastrophic because i couldn't define the Label in the InitializeComponent anymore.

4.)

a.)Read a lot of Stackoverflow-Threads about passing variables between classes, which all didn't helped, all solutions I found, are working between classes, but not in this special case.

b.)Watched a lot of youTube tutorials, same result.

c.)Read some stackoverflow-Threds about passing variables between different Forms, but they all had in common, that the "displaying-form" was opend AFTER the variable was known. In my special case the form is opened all the time, and can't be closed, nor reopened...

And now I am out of ideas! I wouldn't be surprised, if I do not see some details, but I can't found them... I would be very happy, when somebody could help me!

My question:

How can I change the text of my lable from another class?

Answer 1

Your method is static while your form has instance. So your static method does not know anything about your form. You can add MyUserInterface parameter to static method

public static void status_msg(MyUserInterface form, string c_msg)
{
    [...]
    form.f_status.Text = c_msg; // And here is my problem!!
    [...]
}

If you have single instance form (only one instance is created at a time) you can have static property with it's reference:

partial class MyUserInterface
{
    public static MyUserInterface Instance { get; private set; }
    [...]
    public MyUserInterface()
    {
        InitializeComponent();
        Instance = this;
    }
}

With this solution you can use your old method:

class statushandler
{
    [...]
    public static void status_msg(string c_msg)
    {
        [...]
        MyUserInterface.Instance.f_status.Text = c_msg; // You have instance of yout form here
        [...]
    }
}

Of course you should protect against null/ Disposed form etc.

Answer 2

Create a public property on the specific class in your 1st Form that gets the label's value like this:

public string Name {get {return Label1.Text}; set {Label1.Text = value}; }

Then in your 2nd Form:

public Form2(Form1 form)
{
    string name;
    name = form.Name;
}