End Google Ads 201810 - BS.net 01 --> Hi

I have an excel project with two columns Number and name, where Number contains ('4114','8900','3311-123-2').

I read it in c# using:

string connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\\temp\\test.xls;Extended Properties=""Excel 8.0;HDR=YES;""";
command.CommandText = "SELECT Number, Name FROM [Projekter$]";
string nummer = dr["Number"].ToString();

The problem is that '4114','8900' are displayed correct, while '3311-123-2' is empty.

Can anybody please help me?