SharePoint Errors

  • The Web application at “[URL]” could not be found. Verify that you have typed the URL correctly. If the URL should be serving existing content, the system administrator may need to add a new request URL mapping to the intended application.
    (or)
    Retrieving the COM class factory for component with CLSID {BDEADF26-C265-11D0-BCED-00A0C90AB50F} failed due to the following error: 80040154.
    Solution:
    Change the debugging platform from X86 to Any CPU or X64 to Any CPU.
  • One or more field types are not installed properly. Go to the list settings page to delete these fields.
    Solution:
    Check the internal name of the field and use the same name for CAML query.
  • Error occurred in deployment step ‘Activate Features’: 0x80070002
    Solution:
    In my case, this was caused by an invalid ‘ListURL’ setting in my elements.xml file.Be sure the ‘Site URL’ property of your project points to the site that the List resides.If this is pointed to the level above, the list will not be found, and you will get the error above.
    ListURL needs to be ‘Lists/'{your list name} ex. List/Customers, thus you see why it is important for the Site URL to be set properly.
  • Failed to create receiver object from assembly “DLL Name, Version=1.0.0.0, Culture=neutral, PublicKeyToken=03bbc5f953b94a2b”, class “xxxxxxxxxxx.EventReceiver” for feature “FeatureName” (ID: 74C81B9A-D987-4bd1-9438-34E05D8C62BF).:  System.ArgumentNullException: Value cannot be null. Parameter name: type     at System.Activator.CreateInstance (Type type, Boolean nonPublic)    at Microsoft.SharePoint.Administration.SPFeatureDefinition.get_ReceiverObject () ServerX: Failed to create receiver object from assembly “DLL Name, Version=1.0.0.0, Culture=neutral, PublicKeyToken=03bbc5f953b94a2b”, class “xxxxxxxxxxx.EventReceiver” for feature “FeatureName” (ID: 74C81B9A-D987-4bd1-9438-34E05D8C62BF).: System.ArgumentNullException: Value cannot be null. Parameter name: type     at System.Activator.CreateInstance (Type type, Boolean nonPublic)    at Microsoft.SharePoint.Administration.SPFeatureDefinition.get_ReceiverObject ().
    Solution:
    The SharePoint 2010 Timer service cached the old DLL. To fix the issue restart the SharePoint 2010 Timer Service.
  • SharePoint Modal Dialog issue with anchor tag with image button
    Solution:
    Remove the “href: attribute” for anchor tag in SharePoint Modal Dialog.

OCR Using Microsoft Document Imaging API’s in C#.Net

 

OCR: Optical Character Recognition

OCR means extracting the content from images i.e. getting the text from an Image file or scanned PDF, Word and etc. Type of documents.

Steps to implement OCR using Microsoft Document Imaging 

  1. To use Microsoft Document Imaging API we need install any of these software’s Microsoft Office 2007 or SharePoint Designer 2007. In these two software’s SharePoint Designer 2007 is a free software.
  2. Create a console application using visual studio
  3. Add reference of a Microsoft Office Document Imaging 12.0 Type Library which is COM object
  4. Write the below code                                                                                                                                                    OCR1
  5. Execute the application, It will prompt for Image file path                                              OCR2
  6. Actual image                                                                                                                         OCR
  7. Type the Image file path and press Enter                                                                            OCR3
  8. You can see the output of the text from the image                                                            OCR4

Note: The data which has been extracted from images might not be accurate because if the character in the image is blur the MODI will be not able to recognize the exact character and it will consider it as any other default character. So it is completely dependent upon the quality of the image.

WebServices in .Net

Definition

It is a technology introduced by Microsoft in .NET to provide distributed services over network.
Web Service performs the distribution of the logic always in a xml standard.

History

To develop distributed services many technologies are available in the market like DCOM, CORBA, RMI etc. before .NETPicture4

Advantages

  • Easy to develop and use
  • Cross application communication
  • Cross platform Communication
  • Cross Language Communication
  • Supports Firewalls for Security reasons

Standards of Web Services

SOAP (Simple Object Access Protocol)

  • This standard is used for data transformation and data conversion.
  • It contains XML which is the universal understandable format which is used for transferring the request and response in XML format which is called as SOAP Envelope.
  • To take the SOAP Envelope b/w client and service universal communication protocol is used i.e. HTTP
  • Because its port number is configure on most of the firewalls and proxy.

WSDL (Web Service Description language)

  • This standard will describe a web service in an XML Schema.
  • It provides the description about the methods available, method parameters list, type and the return type of the method.
  • It also specifies how the request and responses are perform with the protocols along with the path of a web service.

DISCO (Discovery Standards)

  • This file will maintains the links of WSDL.

UDDI (Universal Discovery Description Integration)

  • It is a centralized repository where all the web services links are maintained in terms of discovery files. (www.UDDI.org)

Architecture

Local Architecture

Picture2

 

  1. When a Client app gives a request it will search the web service and the WSDL file of that web service and the WSDL file of that web service is return back to the client program.
  2. The client program give the WSDL file to proxy class which checks the your request in the description and generates the request object by binding, parameter list, Type and return type.
  3. Request object is converted to XML standard which is called SOAP request Envelope.
  4. SOAP request Envelope is transfer to server using http protocol
  5. The Soap server on the web server will accept the soap request envelope and converts it to an ordinary request object then forward into the web services.
  6. Web service will process the request and gives the response to the SOAP server.
  7. SOAP server will convert the response to SOAP response envelope send it back to the client using http protocol.
  8. The proxy class on the client machine converts the SOAP response object to display the output.

Global Architecture

Picture3

 

  1. When a client wants to search a web service or access a web service the request is first accepted by the UDDI server.
  2. UDDI contains that web service discovery files.
  3. UDDI server choose the discovery file according to the request and return the link of WSDL file to the client.
  4. The client program will give the request to the WSDL file. Then web service will returns the WSDL file to the client.
  5. Remaining steps are same as Local Architecture.

Developing Web Service in ASP.NET

  1. Web Services are stateless
  2. They should save with .asmx(Active Server Method extension) extension.
  3. The method which you want to provide for internet accessibility those should be declare with [WebMethod] attribute.
  4. To develop web service in ASP.NET, .NET framework has provided System.Web.Services namespace.

Developing a Web Service in Notepad

<%@ WebService Language=“C#” Class=“Sample”%>
using System;
using System.Web.Services;
public class Sample
{
[WebMethod]
public int Sum(int a, int b)
{
return a+b;
}
}

  • Save the file with .asmx extension and copy the file to the virtual directory.
  • To test the WebService and to view the description go to browser and type the url of the like ex: http://localhost/aspnet/first.asmx

State Management with Web Services

  • As Web Services are stateless technology whose memory will be allocated with every request and automatically destroys with every response.
  • So to maintain some information on the web service hosted system for a specific time interval we can use state management.
  • State management with web service always supports Server Side State management by using 3 concepts
    1. Sessions  2. Applications 3. Caching

    Sessions with Web Service:

  • Session is some information maintained on a server machine with a default life span of 20 minutes after sending the response.
  • It is local for every user.
  • Session along with Web Services are by default disable so to use the session we should enable it for every Web Method.

    Application object with Web Service:

  • It is similar like session maintaining information on server for life span of 5 minutes after sending the response.
  • It is sharable among more than one user.

    Caching with Web Service:

  • Caching is use to maintain some data, output of webpage in a fast accessing temporary memory i.e. caching memory.

Security with Web Services

  1. If the web service placed under UDDI server anybody can access your web services.
  2. So the UDDI server requires registration before access the web services from it. And to provide the communication between UDDI server and application we require passport services.
  3. In .NET 1.1 version the passport services need to install by downloading from http://www.hotmail.com or http://www.ms.com and then we need to specify authentication, authorization settings in application web.config file.
  4. In the Web.Config file
    <authentication mode = “Passport”>
    <Passport redirecturl = “ ”/>
    </authentication>
  5. From .NET 2.0 version onwards passport services are by default integrated and also they are configured on IIS.