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存储和检索数字化文档是任何文档管理工作流过程的一个重要特征。本文我们将介绍如何使用ASP.NET Web程序中的文档扫描功能将扫描文件保存为PDF文档，并保存至SQL Server数据库中。
在本文中我们将使用来加快文档扫描，上传和显示功能的开发进程。
文件扫描
由于Dynamic Web TWAIN是一个客户端SDK，我们将使用JavaScript来调用它的方法/属性。有了扫描识别工具Dynamic Web TWAIN，你可以自定义扫描设置，如分辨率，像素类型，亮度，对比度，页面大小等。本文，我们将重点介绍如何从SQL Server中储存和检索图像。为此，我们将只包括一个简单的扫描过程。
function acquireImage() {
if (_divDWTSourceContainerID == "") DWObject.SelectSource(); else DWObject.SelectSourceByIndex(document.getElementById(_divDWTSourceContainerID).selectedIndex); //select a TWAIN scanner DWObject.CloseSource(); //make sure the source is closed before using it DWObject.OpenSource(); DWObject.IfShowUI = document.getElementById("ShowUI").checked; //show or hide the user interface of the TWAIN scannervar i;
for (i = 0; i < 3; i++) { if (document.getElementsByName("PixelType").item(i).checked == true) DWObject.PixelType = i; } // set the pixel type of the acquired images, B/W, gray or color DWObject.Resolution = document.getElementById("Resolution").value; //set the resolution DWObject.IfFeederEnabled = document.getElementById("ADF").checked; //scan images from auto feeder DWObject.IfDuplexEnabled = document.getElementById("Duplex").checked; //enable duplex scanning appendMessage("Pixel Type: " + DWObject.PixelType + "<br />Resolution: " + DWObject.Resolution + "<br />");DWObject.IfDisableSourceAfterAcquire = true;
DWObject.AcquireImage(); //start document scanning }将扫描图像作为个多页PDF保存至SQL Server
扫描完成后，你可以将图像保存为多种格式：BMP、PNG、JPG、TIF、PDF、多页PDF或多页TIF。在这个例子中，我们将扫描图像保存为一个多页PDF文件。代码如下所示：
function btnUpload_onclick() {
if (!checkIfImagesInBuffer()) { return; } var i, strHTTPServer, strActionPage, strImageType; _txtFileName.className = ""; if (!strre.test(_txtFileName.value)) { _txtFileName.className += " invalid"; _txtFileName.focus(); appendMessage("Please input file name.<br />Currently only English names are allowed.<br />"); return; } //DWObject.MaxInternetTransferThreads = 5; strHTTPServer = _strServerName; DWObject.HTTPPort = _strPort; var CurrentPathName = unescape(location.pathname); // get current PathName in plain ASCII var CurrentPath = CurrentPathName.substring(0, CurrentPathName.lastIndexOf("/") + 1); strActionPage = CurrentPath + _strActionPage; // the aspx page for receiving image data on the server side var redirectURLifOK = CurrentPath + "online_demo_list.aspx"; var uploadfilename = _txtFileName.value + "." + document.getElementsByName("ImageType").item(i).value;DWObject.HTTPUploadAllThroughPostAsPDF(
strHTTPServer, strActionPage, uploadfilename ); //upload images as multi-page PDF file_strTempStr = _strTempStr + "Upload: ";
if (checkErrorString()) { if (strActionPage.indexOf("SaveToFile") != -1) alert(DWObject.ErrorString)//if save to file. else window.location = redirectURLifOK; } }Action Page- SaveToDB.aspx
动作页面用于接收来自扫描图像的图像数据。
<%@ Page Language="C#"%>
<% try { String strImageName; int iFileLength; HttpFileCollection files = HttpContext.Current.Request.Files; HttpPostedFile uploadfile = files["RemoteFile"]; strImageName = uploadfile.FileName; iFileLength = uploadfile.ContentLength;Byte[] inputBuffer = new Byte[iFileLength];
System.IO.Stream inputStream;inputStream = uploadfile.InputStream;
inputStream.Read(inputBuffer, 0, iFileLength);String strConnString;
strConnString = Common.DW_ConnString;
System.Data.SqlClient.SqlConnection sqlConnection = new System.Data.SqlClient.SqlConnection(strConnString);
String SqlCmdText = "INSERT INTO " + Common.DW_SaveTable + " (strImageName,imgImageData) VALUES (@ImageName,@Image)";
System.Data.SqlClient.SqlCommand sqlCmdObj = new System.Data.SqlClient.SqlCommand(SqlCmdText, sqlConnection);sqlCmdObj.Parameters.Add("@Image", System.Data.SqlDbType.Binary, iFileLength).Value = inputBuffer;
sqlCmdObj.Parameters.Add("@ImageName", System.Data.SqlDbType.VarChar, 255).Value = strImageName;sqlConnection.Open();
sqlCmdObj.ExecuteNonQuery(); sqlConnection.Close(); } catch { } %>从Web页面上显示数据库中检索PDF文件
Online_demo_view.aspx用于显示PDF文档
setTimeout(function () {
var CurrentPathName = unescape(location.pathname); // get current PathName in plain ASCII var CurrentPath = CurrentPathName.substring(0, CurrentPathName.lastIndexOf("/") + 1); var strActionPage = CurrentPath + "online_demo_download.aspx"; //the ActionPage's file path strHTTPServer = location.hostname; DWObject.HTTPPort = location.port==""?80:location.port; var downloadsource = strActionPage + "?iImageIndex=<%=strImageID%>&ImageName=<%=strImageName%>&ImageExtName=<%=strImageExtName%>"; DWObject.HTTPDownloadEx(strHTTPServer, downloadsource,<%=strImageFileType %>); }, 500);online_demo_download.aspx用于检索数据库中的图像
<%@ Page Language="C#"%>
<%
String strExc = ""; try { //Get the image data from the database HttpRequest request = HttpContext.Current.Request;String strImageName;
String strImageExtName; String strImageID;strImageName = request["ImageName"];
strImageExtName = request["ImageExtName"]; strImageID = request["iImageIndex"];String strConnString;
strConnString = Common.DW_ConnString;
System.Data.SqlClient.SqlConnection sqlConnection = new System.Data.SqlClient.SqlConnection(strConnString);
System.Data.SqlClient.SqlCommand sqlCmdObj = new System.Data.SqlClient.SqlCommand("SELECT imgImageData FROM " + Common.DW_SaveTable + " WHERE iImageID= " + strImageID, sqlConnection);sqlConnection.Open();
System.Data.SqlClient.SqlDataReader sdrRecordset = sqlCmdObj.ExecuteReader();
sdrRecordset.Read();
long iByteLength;
iByteLength = sdrRecordset.GetBytes(0, 0, null, 0, int.MaxValue);byte[] byFileData = new byte[iByteLength];
sdrRecordset.GetBytes(0, 0, byFileData, 0, Convert.ToInt32(iByteLength));
sdrRecordset.Close();
sqlConnection.Close();sdrRecordset = null;
sqlConnection = null;Response.Clear();
Response.Buffer = true;if (strImageExtName == "bmp")
{ Response.ContentType = "image/bmp"; } else if (strImageExtName == "jpg") { Response.ContentType = "image/jpg"; } else if (strImageExtName == "tif") { Response.ContentType = "image/tiff"; } else if (strImageExtName == "png") { Response.ContentType = "image/png"; } else if (strImageExtName == "pdf") { Response.ContentType = "application/pdf"; }try
{ String fileNameEncode; fileNameEncode = HttpUtility.UrlEncode(strImageName, System.Text.Encoding.UTF8); fileNameEncode = fileNameEncode.Replace("+", "%20"); String appendedheader = "attachment;filename=" + fileNameEncode; Response.AppendHeader("Content-Disposition", appendedheader);Response.OutputStream.Write(byFileData, 0, byFileData.Length);
} catch (Exception exc) { strExc = exc.ToString(); DateTime d1 = DateTime.Now; string logfilename = d1.Year.ToString() + d1.Month.ToString() + d1.Day.ToString() + d1.Hour.ToString() + d1.Minute.ToString() + d1.Second.ToString() + "log.txt"; String strField1Path = HttpContext.Current.Request.MapPath(".") + "/" + logfilename; if (strField1Path != null) { System.IO.StreamWriter sw1 = System.IO.File.CreateText(strField1Path); sw1.Write(strExc); sw1.Close(); } Response.Flush(); Response.Close(); } } catch (Exception ex) { strExc = ex.ToString(); DateTime d1 = DateTime.Now; string logfilename = d1.Year.ToString() + d1.Month.ToString() + d1.Day.ToString() + d1.Hour.ToString() + d1.Minute.ToString() + d1.Second.ToString() + "log.txt"; String strField1Path = HttpContext.Current.Request.MapPath(".") + "/" + logfilename; if (strField1Path != null) { System.IO.StreamWriter sw1 = System.IO.File.CreateText(strField1Path); sw1.Write(strExc); sw1.Close(); } Response.Write(strExc); } %>转载地址：http://dvqvb.baihongyu.com/