为什么 protected SqlDataReader RunProcedure(..)这段还要写Command.CommandType=CommandType.StoredProcedure;

using System;
using System.Data;
using System.Data.SqlClient;


namespace Wrox.WebModules.Data
{
/// <summary>
/// DbObject 的摘要说明。
/// </summary>
public abstract class DbObject
{
protected SqlConnection Connection;
private string connectionString;

public DbObject(string newConnectionString)
{
connectionString=newConnectionString;
Connection=new SqlConnection(connectionString);

//
// TODO: 在此处添加构造函数逻辑
//
}
protected string ConnectionString
{
get
{
return connectionString;
}
}
private SqlCommand BuildQueryCommand(string storedProcName,IDataParameter[] parameters)
{
SqlCommand command=new SqlCommand(storedProcName,Connection);
command.CommandType=CommandType.StoredProcedure;
foreach(SqlParameter parameter in parameters)
{
command.Parameters.Add(parameter);
}
return command;
}
private SqlCommand BuildIntCommand(string storedProcName,IDataParameter[] parameters)
{
SqlCommand command=BuildQueryCommand(storedProcName,parameters);
command.Parameters.Add(new SqlParameter("ReturnValue",SqlDbType.Int,4,ParameterDirection.ReturnValue,false,0,0,string.Empty,DataRowVersion.Default,null));
return command;
}
protected int RunProcedure(string storedProcName,IDataParameter[] parameters,out int rowsAffected)
{
int result;
Connection.Open();
SqlCommand command=BuildIntCommand(storedProcName,parameters);
rowsAffected=command.ExecuteNonQuery();
result=(int)command.Parameters["ReturnValue"].Value;
Connection.Close();

return result;
}
protected SqlDataReader RunProcedure(string storedProcName,IDataParameter[] parameters)
{
SqlDataReader returnReader;
Connection.Open();
SqlCommand command=BuildQueryCommand(storedProcName,parameters);
command.CommandType=CommandType.StoredProcedure;
returnReader=command.ExecuteReader(CommandBehavior.CloseConnection);
return returnReader;
}
protected DataSet RunProcedure(string storedProcName,IDataParameter[] parameters,string tableName)
{
DataSet dataSet=new DataSet();
Connection.Open();
SqlDataAdapter sqlDA=new SqlDataAdapter();
sqlDA.SelectCommand=BuildQueryCommand(storedProcName,parameters);
sqlDA.Fill(dataSet,tableName);
Connection.Close();
return dataSet;
}
protected void RunProcedure(string storedProcName,IDataParameter[] parameters,DataSet dataSet,string tableName)
{
Connection.Open();
SqlDataAdapter sqlDA=new SqlDataAdapter();
sqlDA.SelectCommand=BuildIntCommand(storedProcName,parameters);
sqlDA.Fill(dataSet,tableName);
Connection.Close();
}


}
}