Dynamic Web TWAIN是一个专为Web应用程序设计的TWAIN扫描识别控件，允许用户从扫描仪扫描文档或从数码相机/采集卡中获取图像，并支持上传和处理本地图像。本文将介绍如何通过TWAIN扫描识别工具Dynamic Web TWAIN实现在Web应用程序中扫描和上传文件。

下载并安装Dynamic Web TWAIN后， 在 "\Dynamsoft\Dynamic Web TWAIN 9.0 Trial\Resources."目录下找到下列文件：

DynamicWebTWAIN.cab/ DynamicWebTWAINx64.cab – the ActiveX control edition for Internet Explorer (IE) 32 bit and 64 bit

DynamicWebTWAINPlugIn.msi - the Plugin Edition for Chrome, Firefox, Safari on Windows

DynamicWebTWAINMacEditionTrial.pkg – the Mac Edition for Chrome, Firefox, Safari on Mac OS X

将上述提到4个Dynamic Web TWAIN 插件文件复制并粘贴到MVC应用程序的Content文件夹中，从而将TWAIN扫描识别控件Dynamic Web TWAIN 嵌入到MVC应用程序。

Dynamic Web TWAIN文档扫描视图

如下面的截图所示，索引页上已添加了一个"Scan" 选项卡。点击 "Scan"，用户将看到使用了Dynamic Web TWAIN插件的Scan.aspx页面。

启动Dynamic Web TWAIN

function DW_CreateControl(bNeebBack) {

var objString = "";

var DWTContainer;

// For IE, render the ActiveX Object

if (DW_InIE) {

objString = "

if (DW_InWindowsX86)

objString += "codebase='" + DW_CABX86Path + "#version=" + DW_VersionCode + "' "; //load 32 bit CAB file for 32 bit Windows

else

objString += "codebase='" + DW_CABX64Path + "#version=" + DW_VersionCode + "' "; //load 64 bit CAB file for 64 bit Windows

var temp = DW_IsTrial ? DW_TRAILCLASSID : DW_FULLCLASSID;

objString += " classid='clsid:" + temp + "' viewastext>";

objString += " ";

objString += " ";

objString += " ";

//objString += " ";

objString += "

";

}

// For non-IE browsers, render the embed object

else {

objString = "

objString += " OnPostTransfer='Dynamsoft_OnPostTransfer' OnPostAllTransfers='Dynamsoft_OnPostAllTransfers'";

objString += " OnMouseClick='Dynamsoft_OnMouseClick' OnPostLoad='Dynamsoft_OnPostLoadfunction'";

objString += " OnImageAreaSelected = 'Dynamsoft_OnImageAreaSelected'";

objString += " OnImageAreaDeSelected = 'Dynamsoft_OnImageAreaDeselected'";

objString += " OnMouseDoubleClick = 'Dynamsoft_OnMouseDoubleClick'";

objString += " OnMouseRightClick = 'Dynamsoft_OnMouseRightClick'";

objString += " OnTopImageInTheViewChanged = 'Dynamsoft_OnTopImageInTheViewChanged'";

if (DW_InWindows)

objString += " pluginspage='" +

else

objString += " pluginspage='" + DW_PKGPath + "'>

"; //load the Mac edition for Chrome, Firefox, Safari on Mac

}

DWTContainer = document.getElementById(DW_DWTContainerID);

DWTContainer.innerHTML = objString;

DWObject = document.getElementById(DW_ObjectName);

}

扫描文档

通过TWAIN扫描识别控件可以从扫描仪中轻松捕获图像。下列JavaScript代码设置了像素类型，分辨率，扫描类型等。

function AcquireImageInner() {

if (DW_DWTSourceContainerID == "")

DWObject.SelectSource();

else

DWObject.SelectSourceByIndex(document.getElementById(DW_DWTSourceContainerID).selectedIndex); //select from the available TWAIN devices

DWObject.CloseSource();

DWObject.OpenSource();

DWObject.IfShowUI = document.getElementById("ShowUI").checked;

var i;

for (i = 0; i < 3; i++) {

if (document.getElementsByName("PixelType").item(i).checked == true)

DWObject.PixelType = i;

} //set the pixel type of the image

DWObject.Resolution = Resolution.value;

DWObject.IfFeederEnabled = document.getElementById("ADF").checked; //whether scan from ADF or flatbed

DWObject.IfDuplexEnabled = document.getElementById("Duplex").checked; //whether do duplex scan

DWObject.IfDisableSourceAfterAcquire = true;

DWObject.AcquireImage(); //acquire images from the scanner

}

上传文档

将图像扫描至Dynamic Web TWAIN后，你可以通过HTTP Post方法，将扫描图像上传到Web服务器。

var DW_ActionPage = "SaveToFile"; //call SaveToFile controller

function btnUpload_onclick(){

var i, strHTTPServer, strActionPage, strImageType;

strHTTPServer = DW_ServerName;

DWObject.HTTPPort = DW_strPort;

var CurrentPathName = unescape(location.pathname); // get current PathName in plain ASCII

var CurrentPath = CurrentPathName.substring(0, CurrentPathName.lastIndexOf("/") + 1);

strActionPage = CurrentPath + DW_ActionPage; //the ActionPage's file path

for(i=0;i<4;i++){

if(document.getElementsByName("ImageType").item(i).checked == true){

strImageType = i + 1;

break;

}

} //choose the image type, JPEG, TIFF, PNG or PDF

var uploadfilename = txt_fileName.value + "." + document.getElementsByName("ImageType").item(i).value;

if (strImageType == 2 && document.getElementById("MultiPageTIFF").checked) {

if ((DWObject.SelectedImagesCount == 1) || (DWObject.SelectedImagesCount == DWObject.HowManyImagesInBuffer)) {

DWObject.HTTPUploadAllThroughPostAsMultiPageTIFF(

strHTTPServer,

strActionPage,

uploadfilename

);

{

DWObject.HTTPUploadThroughPostAsMultiPageTIFF(

strHTTPServer,

strActionPage,

uploadfilename

);

}

} //whether to upload the images as a multi-page TIFF file

else if (strImageType == 4 && document.getElementById("MultiPagePDF").checked) {

if ((DWObject.SelectedImagesCount == 1) || (DWObject.SelectedImagesCount == DWObject.HowManyImagesInBuffer)) {

DWObject.HTTPUploadAllThroughPostAsPDF(

strHTTPServer,

strActionPage,

uploadfilename

);

}

else {

DWObject.HTTPUploadThroughPostAsMultiPagePDF(

strHTTPServer,

strActionPage,

uploadfilename

);

}

} //whether to upload the images as a multi-page PDF file

else {

DWObject.HTTPUploadThroughPostEx(

strHTTPServer,

DWObject.CurrentImageIndexInBuffer,

strActionPage,

uploadfilename,

strImageType

);

}

Controller.cs

public String SaveToFile()

{

String strImageName;

HttpFileCollectionBase files = Request.Files;

HttpPostedFileBase uploadfile = files["RemoteFile"];

strImageName = uploadfile.FileName;

uploadfile.SaveAs(Server.MapPath("~") + "\\UploadedImages\\" + strImageName);

return "";

}