gistfile1.cs

var cnStr = ConfigurationManager.ConnectionStrings["foo"].ConnectionString;
using (var conn = new SqlConnection(cnStr))
using (var cmd = conn.CreateCommand())
{
    // if you use a stord proc, change the type, and put the proc name in CommandText
    cmd.CommandType = CommandType.Text; 
    cmd.CommandText = "IF NOT EXISTS (SELECT fooID FROM table WHERE fooID = @fooID) BEGIN " +
                      "INSERT INTO table (fooID, a, b, c, d) " +
                      "VALUES (@fooID, @a, @b, @c, @d) END";
    var id = cmd.Parameters.Add("@fooID", SqlDbType.Int);
    var a = cmd.Parameters.Add("@a", SqlDbType.NVarChar);
    var b = cmd.Parameters.Add("@b", SqlDbType.DateTime);
    var c = cmd.Paramters.Add("@c", SqlDbType.Int);
    var d = cmd.Parameters.Add("@d", SqlDbType.NVarChar);
    
    conn.Open();
    
    foreach (var row in csvRows)
    {
        id.Value = row.Id;
        a.Value = row.a;
        b.Value = row.b;
        c.Value = row.c;
        d.Value = row.d;
        cmd.ExecuteNonQuery();
    }
}