Calculate Age based on ASP.Net TextBox value using SQL query in C# and VB.Net

its done sir.

i have replace below line.

DateTime birthDate = DateTime.ParseExact(birthdate.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture);

to this line.

String birthdate = txtBirthdate.Text;

the final code for me is as below.

//DateTime birthDate = DateTime.ParseExact(birthdate.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture);
String birthdate = txtBirthdate.Text;
SqlConnection con = new SqlConnection(this.con);
SqlCommand cmd = new SqlCommand("Select DATEDIFF(YEAR,CONVERT(datetime,'" + birthdate + "',103),CONVERT(datetime,ISSUEDATE,103)) FROM TableName", con);
//SqlCommand cmd = new SqlCommand("Select DATEDIFF(YEAR,'" + birthdate.Text + "'SYSDATETIME()", con);
con.Open();
string year = Convert.ToString(cmd.ExecuteScalar());
con.Close();
TxtAge.Text = year;