how to insert date of birth from asp.net page to sql server 2008

Question

how to insert date of birth from asp.net page to sql server 2008

i m using

 str="insert into date values('"+TextBox1.Tex)+ "')";
ad=new SqlDataAdapter (str,CT.connect());
dt = new DataTable();
ad.Fill(dt);

 
query in .cs page but it gives error msg..