如何从服务端下载到本地图片并在Image控件中显示

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根据图片名查询服务端的三种图片，再依次显示在对应的Image控件上。 

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using DevExpress.XtraReports.UI;
using System.Data;
using TRSCore;
using System.Text;
using MESCore;
using DevExpress.DataAccess.EntityFramework;
using System.Collections.Generic;
using System.Windows.Forms;
using System.IO;
using Neodynamic.SDK.Printing;

namespace QCMCore.Reports
{
    public partial class rptQCMCOACard : DevExpress.XtraReports.UI.XtraReport
    {
        public rptQCMCOACard()
        {
            InitializeComponent();
        }
        public rptQCMCOACard(DataTable dt,string sBatchID,string sModelID)
        {
            InitializeComponent();
            this.dtOrd = dt;
            this.sBatchID = sBatchID;
            this.sModelID = sModelID;

            
        }
        DataTable dtOrd = new DataTable();
        DataSet ds = new DataSet();

        string sBatchID = "";
        string sModelID = "";
        string sImage1 = "";
        string sImage2 = "";
        string sImage3 = "";
        private bool View_Iamges()
        {
            TRSNode in_node = new TRSNode("View_Label_In");
            TRSNode out_node = new TRSNode("View_Label_Out");

            try
            {

                sImage1 = "图片1-1.png";
                sImage2 = "图片3-1.png";
                sImage3 = "图片2.png";
                List Imagelist = new List();
                List xrImagelist = new List();
                xrImagelist.Add(xrPictureBox1);
                xrImagelist.Add(xrPictureBox2);
                xrImagelist.Add(xrPictureBox3);
                Imagelist.Add(sImage1);
                Imagelist.Add(sImage2);
                Imagelist.Add(sImage3);
                if (Imagelist != null && Imagelist.Count > 0)
                {
                    for (int i = 0; i < Imagelist.Count; i++)
                    {
                        if (Imagelist[i] != "")
                        {
                            //open a thermal label template
                            // string filePath = Application.StartupPath + "\\UserFile\\Label\\" + sLastSaveFile;

                            #region 服务器文件下载
                            in_node = new TRSNode("View_File_In");
                            out_node = new TRSNode("Cmn_Out");

                            CommonRoutine.SetInMsg(in_node);
                            in_node.ProcStep = '2';
                            in_node.AddString("FILENAME", CommonFunction.Trim(Imagelist[i]));


                            if (CommonRoutine.CallService("BAS", "BAS_View_File", in_node, ref out_node) == false)
                            {
                                return false;
                            }
                            #endregion
                            byte[] bytearay = CommonFunction.RemoveByteOrderMark(out_node.GetBlob("FILEDATA"));
                            if (bytearay != null)
                            {
                                MemoryStream ms_buffer;
                                try
                                {
                                    ms_buffer = new MemoryStream(); //对于要重复使用缓存而不是保存到本地再引用，避免报错：图片已被另一进程中使用
                                    ms_buffer.Write(bytearay, 0, bytearay.Length);
                                    ms_buffer.Position = 0;
                                    xrImagelist[i].Image = null;        //
                                    xrImagelist[i].Image = Image.FromStream(ms_buffer);
                                    string filedata = System.Text.Encoding.Default.GetString(bytearay);
                                }
                                catch (Exception ex)
                                {
                                    CommonFunction.ShowMsgBox(ex.Message);
                                }
                            }
                        }
                    }
                    return true;
                }
                else
                {
                    return false;
                }
            }
            catch (Exception ex)
            {
                CommonFunction.ShowMsgBox(ex.Message);
                return false;
            }
        }
        private bool FillHeader()
        {
            try
            {
                if (dtOrd == null)
                {
                    CommonFunction.ShowMsgBox("请先选择需要打印的ITEM！");
                    return false;
                }
                this.xrtBatchID.Text = sBatchID;
                this.xrtModel.Text = sModelID;
                if (View_Iamges()==false )
                {
                    CommonFunction.ShowMsgBox("图片找不到！");
                    return false;
                }
                //this.xrPictureBox1.ImageUrl = Application.StartupPath + "\\UserFile\\Images\\图片1-1.png";
                //this.xrPictureBox2.ImageUrl = Application.StartupPath + "\\UserFile\\Images\\图片3-1.png";
                //this.xrPictureBox3.ImageUrl = Application.StartupPath + "\\UserFile\\Images\\图片2.png";
                this.xrtDateTime.Text = DateTime.Now.ToShortDateString().ToString();    // 20018-9-4
                if (dtOrd.Rows.Count > 0)
                {
                    ds.Clear(); 
                    ds.Tables.Add(dtOrd.Copy());    //使用Copy的Table，以免报错：DataTable已存在另一个DataSet
                    XtraReport report = new XtraReport();
                    report.DataSource = ds;
                    report.DataMember = "queryProducts";
                    List list = new List();
                    for (int i = 0; i < dtOrd.Rows.Count;i++) {

                        DataTable dt = new DataTable();
                        dt.Columns.Add("ITEM_SEQ");
                        dt.Columns.Add("TESTING_ITEM");
                        dt.Columns.Add("TESTING_RESULT");
                        dt.Columns.Add("TESTING_SPECIFICATION");
                        dt.Columns.Add("DIMENS");
                        dt.Columns.Add("TESTING_METHOD");

                        dt.Rows.Add(dtOrd.Rows[i].ItemArray);
                        list.Add(dt);
                    }

                    XRTable table = new XRTable();
                    
                    for (int i = 0; i < dtOrd.Rows.Count; i++)
                    {
                        if (list[i]!=null) {
                        XRTableRow row = new XRTableRow();
                        XRTableCell TESTING_ITEM = new XRTableCell();
                        XRTableCell TESTING_RESULT = new XRTableCell();
                        XRTableCell TESTING_SPECIFICATION = new XRTableCell();
                        XRTableCell DIMENS = new XRTableCell();
                        XRTableCell TESTING_METHOD = new XRTableCell();

                        row.Cells.Add(TESTING_ITEM);
                        row.Cells.Add(TESTING_RESULT);
                        row.Cells.Add(TESTING_SPECIFICATION);
                        row.Cells.Add(DIMENS);
                        row.Cells.Add(TESTING_METHOD);
                        //TESTING_ITEM.WidthF = 140.14f;
                        //TESTING_RESULT.WidthF = 140.14f;
                        //TESTING_SPECIFICATION.WidthF = 140.14f;
                        //DIMENS.WidthF = 140.14f;
                        //TESTING_METHOD.WidthF = 140.14f;
                        TESTING_ITEM.DataBindings.Add("Text", list[i], "TESTING_ITEM");
                        TESTING_RESULT.DataBindings.Add("Text", list[i], "TESTING_RESULT");
                        TESTING_SPECIFICATION.DataBindings.Add("Text", list[i], "TESTING_SPECIFICATION");
                        DIMENS.DataBindings.Add("Text", list[i], "DIMENS");
                        TESTING_METHOD.DataBindings.Add("Text", list[i], "TESTING_METHOD");
                        xrTable7.Rows.Add(row);
                            //xrTable7.InsertRowBelow(xrTable7.Rows[i]);
                        }
                    }
                    
                    DetailBand detailBand = new DetailBand();
                    detailBand.Controls.Add(table);
                    report.Bands.Add(detailBand);
                   

                }

                return true;
            }
            catch (Exception ex)
            {
                CommonFunction.ShowMsgBox(ex.Message);
                return false;
            }
        }

        private void ReportHeader_BeforePrint(object sender, System.Drawing.Printing.PrintEventArgs e)
        {
            FillHeader();
        }


    
    }
}

 =========初试代码有bug

   private bool View_Iamges()
        {
            TRSNode in_node = new TRSNode("View_Label_In");
            TRSNode out_node = new TRSNode("View_Label_Out");

            try
            {

                sImage1 = "图片1-1.png";
                sImage2 = "图片3-1.png";
                sImage3 = "图片2.png";
                List Imagelist = new List();
                Imagelist.Add(sImage1);
                Imagelist.Add(sImage2);
                Imagelist.Add(sImage3);
                if (Imagelist != null && Imagelist.Count > 0)
                {
                    for (int i = 0; i < Imagelist.Count; i++)
                    {
                        if (Imagelist[i] != "")
                        {
                            //open a thermal label template
                            // string filePath = Application.StartupPath + "\\UserFile\\Label\\" + sLastSaveFile;

                            #region 服务器文件下载
                            in_node = new TRSNode("View_File_In");
                            out_node = new TRSNode("Cmn_Out");

                            CommonRoutine.SetInMsg(in_node);
                            in_node.ProcStep = '2';  //查询对应的文件夹
                            in_node.AddString("FILENAME", CommonFunction.Trim(Imagelist[i]));


                            if (CommonRoutine.CallService("BAS", "BAS_View_File", in_node, ref out_node) == false)
                            {
                                return false;
                            }
                            #endregion
                            byte[] bytearay = CommonFunction.RemoveByteOrderMark(out_node.GetBlob("FILEDATA"));
                            if (bytearay != null)
                            {
                                string filedata = System.Text.Encoding.Default.GetString(bytearay);
                                //保存Label文件到本地，进行编辑
                                string filePath = Application.StartupPath + "\\UserFile\\Images\\" + Imagelist[i];
                                File.WriteAllBytes(filePath, bytearay);
                                string picPath = filePath.Substring(0, filePath.Length - 4) + ".png";//本地Label图片路径


                                if (!File.Exists(picPath))//如果图片不存在，生成
                                {
                                    ThermalLabel tl = ThermalLabel.CreateFromXmlTemplate(filedata);

                                    //Display ThermalLabel as a TIFF image
                                    if (tl != null)
                                    {
                                        //替换DataField，使其显示
                                        foreach (Item item in tl.Items)
                                        {
                                            if (item.DataField != "")
                                            {
                                                item.DataField = "";//必须置为空，否则无法显示
                                            }
                                        }

                                        using (PrintJob pj = new PrintJob())
                                        {
                                            pj.ThermalLabel = tl;
                                            pj.Copies = 1;
                                            MemoryStream ms = new MemoryStream();

                                            ImageSettings imgSett = new ImageSettings();
                                            imgSett.ImageFormat = Neodynamic.SDK.Printing.ImageFormat.Png;
                                            //imgSett.PixelFormat = PixelFormat.BGRA32;
                                            imgSett.AntiAlias = true;
                                            //imgSett.TransparentBackground = true;

                                            pj.ExportToImage(picPath, imgSett, 300);
                                        }
                                    }
                                }
                                //在对应的控件中显示
                                if (i == 0)
                                    xrPictureBox1.Image = Image.FromFile(picPath);
                                if (i == 1)
                                    xrPictureBox2.Image = Image.FromFile(picPath);
                                if (i == 2)
                                    xrPictureBox3.Image = Image.FromFile(picPath);

                            }
                        }
                    }
                    return true;
                }
                return false;
            }
            catch (Exception ex)
            {
                CommonFunction.ShowMsgBox(ex.Message);
                return false;
            }
        }

注：

1、当所用的图片需要被重复引用时，将图片从服务端下载至本地再引用的做法容易报错：图片正由另一个进程使用。

解决方法，一是使用File.WriteAllBytes()方法时，记得释放资源。

二是使用内存的方式直接将图片填充至控件上，而不是将图片下载至客户端，再填充。

  MemoryStream ms_buffer;
                                try
                                {
                                    ms_buffer = new MemoryStream(); //对于要重复使用缓存而不是保存到本地再引用，避免报错：图片已被另一进程中使用
                                    ms_buffer.Write(bytearay, 0, bytearay.Length);
                                    ms_buffer.Position = 0;
                                    xrImagelist[i].Image = null;        //
                                    xrImagelist[i].Image = Image.FromStream(ms_buffer);
                                    string filedata = System.Text.Encoding.Default.GetString(bytearay);
                                }
                                catch (Exception ex)
                                {
                                    CommonFunction.ShowMsgBox(ex.Message);
                                }

2、当传入的DataTable被重复使用时，容易报错：DataTable已属于另一个DataSet。

解决方法就是添加克隆表或复制的表到DataSet中。

 ds.Tables.Add(dtOrd.Copy());

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