C# Parametreli Metod Fonksiyonu

protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
    {
        if (Session["madi"] != null)
        {
            string isim = Session["madi"].ToString();
            cariuygulamaSayac(isim);
        }
        else
        {
            string isim = "KULLANICI";
            cariuygulamaSayac(isim);
        }
    }

public void cariuygulamaSayac(string kullanici)
    {

        cariSql.SelectCommand = "SELECT * FROM cariuygulama WHERE musteri_adi = '" + kullanici + "' ";

        if (!(((DataView)cariSql.Select(DataSourceSelectArguments.Empty)).Count.Equals(0)))
        {
            SqlConnection baglanti = new SqlConnection(cs1);

            SqlCommand sorgu = new SqlCommand("Select indirme from cariuygulama WHERE musteri_adi = '" + kullanici + "'", baglanti);
            baglanti.Open();
            int indirme = (int)sorgu.ExecuteScalar();
            baglanti.Close();

            indirme++;
            try
            {
                if (baglanti.State == ConnectionState.Closed)
                    baglanti.Open();

                string kayit = "UPDATE cariuygulama SET indirme=@ci where musteri_adi=@ma";
                SqlCommand komut = new SqlCommand(kayit, baglanti);
                komut.Parameters.AddWithValue("@ma", kullanici);
                komut.Parameters.AddWithValue("@ci", indirme);


                komut.ExecuteNonQuery();
                baglanti.Close();
                Response.Redirect("apk/cariapk.rar");


            }
            catch (Exception hata)
            {

            }


        }
        else
        {
            SqlConnection baglanti = new SqlConnection(cs1);

            try
            {
                if (baglanti.State == ConnectionState.Closed)
                    baglanti.Open();
                string zaman = DateTime.Now.ToString();
                string kayit = "insert into cariuygulama (musteri_adi,tarih,indirme) values ('"+kullanici+"','"+zaman+"', 1)";
                SqlCommand komut = new SqlCommand(kayit, baglanti);

                komut.ExecuteNonQuery();
                baglanti.Close();

                Response.Redirect("apk/cariapk.rar");



            }
            catch (Exception hata)
            {
               
            }

        }

    }