如何通过单击另一个用户控件中的按钮来在用户控件的文本框中显示一些文本？

Question

please be kind enough to note that I'm new to visual studio.I have a form named form1 in it I have 2 user controls namely uctxt and ucbtn. uctxt has a textbox named txt1 and ucbtn has a button named btn1.
I need to fill txt1 with some text by clicking btn1(I tried public modifiers). I searched everywhere on the internet for a solution for this and I found nothing.

I tried:

public void Btn1_Click(object sender, EventArgs e)
        {
            uctxt ucText = new uctxt();
            ucText.txt1.Text = "welcome";
        }

Answer 1

You need at least to expose the OnClick event on the ucbtn :

public event EventHandler UserControlButtonClick;

protected void Btn1_Click(object sender, EventArgs e) =>     
    if (this.UserControlButtonClick != null)
        this.UserControlButtonClick(this, e);

And the label on the uctxt :

public String UserControlLabelText
{
    get{return txt1.Text;}
    set{txt1.Text = value;}
}

After that you can use them both from the main form like this:

ucbtn1.UserControlButtonClick += new EventHandler(ucbtn1_ButtonClick);

protected void ucbtn1_ButtonClick(object sender, EventArgs e)
{
    uctxt1.UserControlLabelText = "your text";
}