Why the data are not updating in table

void submit(Object s, EventArgs e)
{
con.Open();
com=con.CreateCommand();
if(con!=null)
{
com.CommandText="UPDATE joining SET aname = '" + txtName.Text.Trim() + "',fathname='" +   txtFather.Text.Trim()+ "' where refno='" + txtRefNo.Text.Trim() + "'";
try{
com.ExecuteNonQuery();
System.Web.UI.WebControls.Label lbl1=new System.Web.UI.WebControls.Label();
lbl1.ForeColor=System.Drawing.Color.Yellow;
lbl1.BackColor=System.Drawing.Color.Blue;
lbl1.Text="Your record UPDATED sucessfully";
ph1.Controls.Add(lbl1);
}
catch(Exception ex)
{
Response.Write(ex.Message);
}}
con.Close();
}