C #登录代码

try
{
    string NameStr=this.txtName.Text;
    string AgeStr =this.txtAge.Text;
    SqlConnection conn = new SqlConnection("Data Source=hetao;Initial Catalog=TestDB;Integrated Security=True");
    conn.Open();
    SqlCommand cmd=new SqlCommand("select count(*) as flag from T_UserName where name="+"'"+NameStr+"'"+"and age ="+"'"+      AgeStr+"'",conn);
    cmd.ExecuteNonQuery();
    int flag=Convert.ToInt32(cmd.ExecuteScalar().ToString());
               
    if(flag>0)
    {
         frmMain fm = new frmMain();
         fm.Show();
         this.Hide();
    }
    else
    {
        this.labelX3.Enabled=true;
        this.labelX3.Text="出错";
        this.labelX3.Visible=true;   
    }


    
}
catch
{
    MessageBox.Show("用户名和密码错误");
}