Question

c# 如何在form2的button1上单击，form1的textbox1就显示"aaaaa"

Answer 1

需要在Form2上添加Form1的引用

Public class Form1
{
public void SetTextbox1Value(string value)
{
this.textbox1.text = value;
}
}

public class Form2
{
.....
public void SetForm1(Form1 frm)
{
_form1 = frm;
}
private Form1 _form1;

private void button1_Click(object sender, EventArgs e)
{
if(_form1 !=null)
{
_form1.SetTextbox1Value("aaaaa")
}
}

}

在初始化Form2时候
Form2 frm2 = new Form2();
frm. SetForm1(frm1);
frm.Show();

Answer 2

form1上写个函数fuc1,让textbox1显示aaaa
form2.onbutton1click += fuc1
具体看函数代理、事件的资料

Answer 3

在form2的
private void button1_Click(object sender, EventArgs e)
{
Form1 form1 = new Form1("aaaaa");
form1.Show();
}
在form1的
public Form1(string aa)
{
InitializeComponent();
TextBox1.Text = aa;
}