How to change a label on Form1 from Form2?

John Beeman

I am having trouble changing a label on a different form. Can anyone tell me what I'm doing wrong here? Thanks.

On Form 1, I have the following, where label1 is defined in Form1.Designer:

public string Lbl
        {
            get {
                return label1.Text;
            }
            set {
                label1.Text = value;
                MessageBox.Show(label1.Text); //Debug: Value here shows correctly but label does not actually change on Form
            }
        }

On Form2 I have this:

        void setLabelInForm1()
        {
            Form1 frm1 = new Form1();
            frm1.Lbl = "LOADED";
        }

private void button1_Click_1(object sender, EventArgs e)
        {
                ........................
                setLabelInForm1();
                .......................
        }

3 Replies

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Alan18y ago
Accepted answer
A further thought here.

If Form1 is the start up form, then you don't want to create a new instance - you want to access the existing instance:

        void setLabelInForm1()
        {
            Form1 frm1 = (Form1)Application.OpenForms["Form1"];
            frm1.Lbl = "LOADED";
            frm1.Visible = true; // if necessary
        }
John Beeman18y ago
Works perfectly. Thanks for both answers.
Satish Kathi18y ago
You are not displaying the Form1 hence you are not seeing the value. Just add frm1.Show(); after assigning the value to the Label. See the code below in bold font

public string Lbl
        {
            get {
                return label1.Text;
            }
            set {
                label1.Text = value;
                MessageBox.Show(label1.Text); //Debug: Value here shows correctly but label does not actually change on Form
            }
        }

On Form2 I have this:

        void setLabelInForm1()
        {
            Form1 frm1 = new Form1();
            frm1.Lbl = "LOADED";

            frm1.Show();
        }

private void button1_Click_1(object sender, EventArgs e)
        {
                ........................
                setLabelInForm1();
                .......................
        }