Solution HERE

https://dwpsislampur.com/ #/

Simple Asp.net AJAX Example of update Textbox:-
Design page:- .aspx











 

 



 

 

 





UpdatePanel1







 

 



 

 

 



Outside UpdatePanel




 

 



 

 

 





UpdatePanel2






 

 







coding page:- .aspx.cs
protected void Button1_Click(object sender, EventArgs e)
{
TextBox1.Text = DateTime.Now.ToString();
TextBox2.Text = DateTime.Now.ToString();
TextBox3.Text = DateTime.Now.ToString();
}

protected void Button2_Click(object sender, EventArgs e)
{
TextBox1.Text = DateTime.Now.ToString();
TextBox2.Text = DateTime.Now.ToString();
TextBox3.Text = DateTime.Now.ToString();
}

protected void Button3_Click(object sender, EventArgs e)
{
TextBox1.Text = DateTime.Now.ToString();
TextBox2.Text = DateTime.Now.ToString();
TextBox3.Text = DateTime.Now.ToString();
UpdatePanel1.Update();
}