WCF中out,ref参数

IOutputStreamService.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.IO;
using System.Net;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Data;
using System.Drawing;

namespace WcfStream
{
    [ServiceContract]
    public interface IOutputStreamService
    {
        [OperationContract]
        Stream OutStream(Stream s);

        [OperationContract]
        string GetStr(string str);

        [OperationContract]
        void OutArgs(out string outstr1, out string outstr2, out string outstr3);

        [OperationContract]
        void InArgs(ref string refstr);

        [OperationContract]
        void RefOutArgs(ref string refstr, out string outstr);  //先有传入参数，后有传出参数

        [OperationContract]
        void OutRefArgs(out string outstr, ref string refstr);  //先有传入参数，后有传出参数

        [OperationContract]
        void GetDataTableByRefArgs(out DataTable datatable, ref string sql);

        //[OperationContract]
        //void GetImgFromClient(Bitmap img);  错误 Bitmap类型不能传递
    }


}

OutputStreamService.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.IO;
using System.Net;
using Microsoft.Win32;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Data;
using System.Drawing;

namespace WcfStream
{
    public class OutputStreamService : IOutputStreamService
    {
        public Stream OutStream(Stream s)
        {
            //IntPtr FileP = File.Open(@"C:\1.mp3", FileMode.OpenOrCreate, FileAccess.Read).Handle;
            //s = new FileStream(FileP, FileAccess.Read);
            return s;
        }

        public string GetStr(string str)
        {
            //Console.WriteLine(str);
            //str = "ABC";
            return str;
        }

        public void OutArgs(out string outstr1, out string outstr2, out string outstr3)
        {
            outstr1 = "第一个out参数.";
            outstr2 = "第二个out参数.";
            outstr3 = "第三个out参数.";
        }

        public void InArgs(ref string RefStr)
        {
            RefStr += "服务器端自己加点料.";  //ResStr 初始值是客户端赋予的,客户端可以进一步处理
            //MessageBox.Show(RefStr);
        }
        public void RefOutArgs(ref string refstr, out string outstr)
        {
            outstr = refstr;
            //MessageBox.Show(outstr);
        }

        public void OutRefArgs(out string outstr, ref string refstr)  //先有传入参数，后有传出参数
        {
            //outstr = "服务器给传出值";
            outstr = refstr;  //传出值由传入值赋值
            //MessageBox.Show(outstr);
        }

        public void GetDataTableByRefArgs(out DataTable datatable, ref string sql)
        {
            SqlConnection conn = new SqlConnection(@"Data Source=WIN-1DHKKCMTGTE\SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=True");
            conn.Open();
            SqlDataAdapter sda = new SqlDataAdapter(sql, conn);
            DataSet ds = new DataSet();
            sda.Fill(ds);
            datatable = ds.Tables[0];
        }

        public void GetImgFromClient(Bitmap img)   //没有ref和out修饰的参数,谁调用谁给值，这点要记清楚!
        {
            img.Save(@"C:\111.jpg");
        }

    }
}

调用代码Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.IO;
using System.Windows.Forms;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            ServiceReference1.OutputStreamServiceClient sc = new ConsoleApplication1.ServiceReference1.OutputStreamServiceClient();
            Console.WriteLine(sc.GetStr("客户端赋值的字符串！"));

            #region out 参数 begin 【out参数传递方向是从定义方法的地方开始传到调用方法的地方】
            string outstr1;
            string outstr2;
            string outstr3;
            outstr1 = sc.OutArgs(out outstr2, out outstr3);  //outstr1跑哪儿去了?第一个参数这边成了函数的执行返回值
            Console.WriteLine(outstr1 + ":" + outstr2 + ":" + outstr3);
            #endregion

            #region Ref 参数 begin   【ref参数叫传入参数，所以开始要有初始化，并且由被调用方给予初值】
            string instr1 = "Ref参数的值由客户端赋值";
            sc.InArgs(ref instr1);
            #endregion

            #region Ref-Out 参数  begin
            string refstr = "客户端是老大，老大给初值";
            string outstr;
            //Console.WriteLine(sc.OutInArgs(ref refstr,out outstr));  //看看输出结果是什么? 错误,函数返回值是第一个参数?
            sc.RefOutArgs(ref refstr, out outstr);
            #endregion

            #region Out-Ref 参数 begin
            //sc.OutRefArgs(ref refstr);
            Console.WriteLine(sc.OutRefArgs(ref refstr));  //out参数此时成了函数返回值
            #endregion Out-Ref 参数 end  //参数里只要有ref,函数里ref的值优先于out得到值

            #region 传入 sql 得到 查询结果
            string sql = "select top 10 * from orders";
            Console.WriteLine(sc.GetDataTableByRefArgs(ref sql).Rows[0][0]);
            #endregion

            Console.ReadLine();


        }
    }
}