指定的转换无效-例外

Question

I have following situation. I have PL/SQL - where I clicked "Describe" button on table and it told me type of one column is "INTEGER". On the C# side I have this code to read that value:

    // GET ID
   if (!rdr.IsDBNull(rdr.GetOrdinal("ID")))
   {
      int ID =  rdr.GetInt32(rdr.GetOrdinal("ID")); // Here I get exception
   }

But I get this exception:

Specified cast is not valid.

Can anyone help?

Stack trace:

StackTrace " at Oracle.DataAccess.Client.OracleDataReader.GetInt32(Int32 i)\\r\\n at GatewayFileImporter.Form1.button1_Click(Object sender, EventArgs e) in c:\\Users\\g\\Documents\\Visual Studio 2012\\Projects\\FileImpo\\FileImpo\\Form1.cs:line 86" string

Answer 1

From Oracle Data Type Mappings

This data type is an alias for the NUMBER(38) data type, and is designed so that the OracleDataReader returns a System.Decimal or OracleNumber instead of an integer value. Using the .NET Framework data type can cause an overflow.

Looks like this mapped to decimal in .NET side and you need to use GetDecimal method instead;

decimal ID =  rdr.GetDecimal(rdr.GetOrdinal("ID"));