i'm fined a nice solution take it
step1:
your form should contain
1- tow textbox one of them visible=false
2- calender
step2:
//code under calender
TextBox1.Text = Calendar1.SelectedDate.ToShortDateString().ToString();//this textbox visible=false
if (TextBox1.Text == "7/1/2011")
{
TextBox2.Text = "meeting";
}
else
{
TextBox2.Text = TextBox1.Text;
}
step3:
to fill 30 days use elseif(){}