"ORA-01036: illegal variable name/number\n" for oracle clob in C#

Question

When I try to create an oracle stored procedure call with clob input and output in C#, I get the following error:

ORA-01036: illegal variable name/number\n

Here's the code itself:

OracleTransaction transaction = connection.BeginTransaction();
OracleCommand command = connection.CreateCommand();
command.Transaction = transaction;
command.CommandText = 
      @"declare xx clob; 
      begin dbms_lob.createtemporary(xx, false, 0); 
      :tempclob := xx; end;";

command.Parameters.Add(new OracleParameter("tempclob", OracleType.Clob))
    .Direction = ParameterDirection.Output;

command.ExecuteNonQuery();

OracleLob tempLob = (OracleLob)command.Parameters[0].Value;
//byte[] tempbuff = new byte[10000];
byte[] tempbuff = System.Text.Encoding.Unicode.GetBytes(generateXMLMessage());

tempLob.BeginBatch(OracleLobOpenMode.ReadWrite);
tempLob.Write(tempbuff, 0, tempbuff.Length);
tempLob.EndBatch();
command.Parameters.Clear();
command.CommandText = "InsertMessageAndGetResponseWRP";
command.CommandType = CommandType.StoredProcedure;
//command.Parameters
//.Add(new OracleParameter("ImportDoc", OracleType.Blob)).Value = tempLob;
command.Parameters.Add(new OracleParameter("iSourceSystem", OracleType.VarChar))
       .Value = "XXX";

command.Parameters.Add(new OracleParameter("iMessage", OracleType.Clob))
       .Value = tempLob;


command.Parameters.Add(new OracleParameter("iResponseMessage", OracleType.Clob)).Direction = ParameterDirection.Output;
command.Parameters.Add(new OracleParameter("retVar ", OracleType.Int32)).Direction = ParameterDirection.Output;

command.ExecuteNonQuery();
transaction.Commit();

Answer 1

Just try

command.CommandText = 
      @"declare xx clob; 
      begin dbms_lob.createtemporary(xx, false, 0); 
      tempclob := xx; end;";

Replace :tempclob with tempclob.

Answer 2

Which of the two calls to ExecuteNonQuery() is generating the error? I'm guessing it's the second one.

I don't do C#, but from several examples I found online, it looks like when you are using the StoredProcedure command type, you don't want to create actual OracleParameter objects. Instead, you initialize the parameters like this:

command.Parameters.Add("iSourceSystem", OracleType.VarChar).Value = "XXX";

Answer 3

command.Parameters.Add("iSourceSystem", OracleType.VarChar).Value = "XXX";

same error is coming.

Replace :tempclob with tempclob.

error at first ExecuteNonQuery()