vb.net 调用oracle中存储过程

存储过程的实例:
PROCEDURE TEST_C(temp out varchar2,a INvarchar2, b in varchar2)
IS
BEGIN
temp:=a || b;
END;

调用方法:
说明:要在程序开头加入Imports System.Data.OleDb

Dim dbConn As New OleDbConnection
Dim dbComm As OleDbCommand

dbConn.ConnectionString = "Provider=MSDAORA.1;User ID=xxx;Password=xxx;Data Source=xxx;"
dbConn.Open()
dbComm = dbConn.CreateCommand

dbComm.Parameters.Add("temp", OleDbType.VarChar, 30).Direction = ParameterDirection.Output
dbComm.Parameters.Add("a", OleDbType.VarChar, 30).Direction = ParameterDirection.Input
dbComm.Parameters("a").Value = "test "
dbComm.Parameters.Add("b", OleDbType.VarChar, 30).Direction = ParameterDirection.Input
dbComm.Parameters("b").Value = "OK"

dbComm.CommandText = "{CALL TEST_C(?,?,?)}" '这里就是使用"？"来代替参数
dbComm.CommandType = CommandType.Text
dbComm.ExecuteNonQuery()
dbConn.Close()

MessageBox.Show(dbComm.Parameters("temp").Value)