我设计中的文字标签文字不会更改

Question

I have a text label inside of Form1 named txtOn . I have made its modifier to public . Now I attempt to change the text using the following code with the click of a button. Nothing happens, but button clicked! is logged to debug.

How can I make the text of the text label change successfully?

  private void button1_Click(object sender, EventArgs e)
    {
        Form1 home = new Form1();
        home.txtOn.Text = "test!";

        System.Diagnostics.Debug.WriteLine("button clicked!");
    }

Answer 1

You probably want either

// Start NEW Form1, show it and change the button
private void button1_Click(object sender, EventArgs e)
{
    Form1 home = new Form1();

    home.txtOn.Text = "test!";
    home.Show(); // <- do not forget to show the form

    System.Diagnostics.Debug.WriteLine("button clicked!");
}

or

// On the EXISTING Form1 instance change the button
// providing that "button1_Click" method belongs to "Form1" class
private void button1_Click(object sender, EventArgs e)
{
    txtOn.Text = "test!";

    System.Diagnostics.Debug.WriteLine("button clicked!");
}

Answer 2

Is not working because you are re instantiating Form1 when it's already available. You are changing the text of a button not on the same instance as the one on the ui

Try

private void button1_Click(object sender, EventArgs e) 
{ 

        txtOn.Text = "test!";

}

.

Answer 3

NO, change that labels text in your Form load or initialize method like

private void button1_Click(object sender, EventArgs e)
    {
        Form1 home = new Form1();
        home.Show();     
        System.Diagnostics.Debug.WriteLine("button clicked!");
    }

Public Form1()
{
  txtOn.Text = "test!";
}

Assuming you are trying to open a different form altogether. If it's the same form then you don't need to create a separate form instance at all. You can just say txtOn.Text = "test!";

Answer 4

You must create Form1 only once. Sample

`Form1 home = new Form1();
home.button1.Click += new System.EventHandler(this.button1_Click);

private void button1_Click(object sender, EventArgs e)
    {

        home.txtOn.Text = "test!";

        System.Diagnostics.Debug.WriteLine("button clicked!");
    }`

Answer 5

It is because you haven't loaded the new instance of form1.

Form1 home = new Form1();
home.show();
home.txton.text="test!";

If you want to change it on the current instance of the form you will need to use the this keyword:

this.txton.text="test!";

Answer 6

You need to expose your label or its property.

In form 2

public string LabelText
    {
        get
        {
            return this.txtOn.Text;
        }
        set
        {
            this.txtOn.Text = value;
        }
    }

Then you can do:

form2 frm2 = new form2();
frm2.LabelText = "test";

Answer 7

You are creating one more object of the same form again. So the label not getting changed. Try the code bellow.

private void button1_Click(object sender, EventArgs e)
    {
        txtOn.Text = "test!";

        System.Diagnostics.Debug.WriteLine("button clicked!");
    }