Hi friends this is a simple program for password change. I am having an exception in it can anyone pls help me in improving this code.

protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {
        cmd.Connection = con;
        con.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["loginconnectionstring"].ConnectionString;
        con.Open();
        if (TextBox3.Text != TextBox2.Text)
        {
            Label5.Visible = true;
            Label5.Text = "Password Doesn't Match Please try Again";
        }
            cmd .CommandType=CommandType .StoredProcedure;
            cmd .CommandText="passchange";
            cmd .Parameters .AddWithValue("@uname", TextBox4.Text);
            cmd .Parameters .AddWithValue ("@pass", TextBox2 .Text);
            cmd .ExecuteNonQuery();
            Label7.Visible = true;
            Label7.Text = "Password Updated Successully";
        }
        catch(Exception ex)
        {
            Label6 .Visible =true;
            Label6 .Text = ex .ToString();
        }
        finally 
        {
            con .Close();
        }
    }

ALTER proc [dbo].[passchange] 
(
@uname varchar(50),@upass varchar(50)
)
as
update test3 set pass=@upass where username=@uname