Delete from TABLE using Comma Separted Values + ORACLE

[sonia.sardana]

I have three records in table with roll numbers 1,2,3.

I want to delete the records from the table using C#.

protected void Button1_Click(object sender, EventArgs e)
    {
        string sRollNos="";
        for (int i = 1; i <= 3; i++)
        {
            if (sRollNos == "")
            {
                sRollNos = i.ToString ();
            }
            else
                sRollNos = sRollNos + "," + i;
        }

        OracleCommand cmd = new OracleCommand("USP_DEL_TBL_STUDENT_DATA", con);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.Add("@p_ROLL",sRollNos );

        if (con.State == ConnectionState.Closed)
        {
            con.Open();
        }
        cmd.ExecuteNonQuery();
    }

I am getting the error-
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 1.

Roll column datatype is Number.

Stored Procedure-

create or replace
PROCEDURE           "USP_DEL_TBL_STUDENT_DATA"
(
p_ROLL IN TBL_STUDENT.ROLL%TYPE
) AS
BEGIN
  DELETE FROM TBL_STUDENT where roll in (p_roll);
  end;

Can somebody help me out!!!