The following example shows the complete query operation. Before linq to xml we were used xmldocument for manipulations in xml like adding attributes, elements and so on. In order to demonstrate these type relationships, most of the examples that follow use explicit typing for all variables. Convert documents to pdf files from windows application mode 3. I figured i should put some example data in and explain better. Linq to xml is a linqenabled, inmemory xml programming interface that enables you to work with xml from within the. This is similar to the regular wa y of querying data in a relational model. Net that extends these languages with query operators and some other features that make it possible to integrate queries in the languages. Save as a linearized file which is most popular and effective format for quick pdf viewing. New suggestion html renderer for pdf using pdfsharp. Linq offers easy transformation for conversion of one data type to another like. Linq to xml is like the document object model dom in that it brings the xml document into memory. Net class library allowing applications to create pdf files.
How to group by and sum in linq solutions experts exchange. Linq to sql fully supports transactions, views, and stored procedures. Microsofts query language is fully integrated and offers easy data access from inmemory objects, databases, xml documents, and many more. With linq, a query is a firstclass language construct, just like classes, methods, events. Convert documents to pdf files from windows service mode 4. Net linq defines a set of query operators can be used to query, project, and filter data data can be in arrays, enumerables, xml, and databases querying handled by the linq engine results returned as a collection of inmemory objects that can be iterated on. For example, linq to objects works on ienumerable s and with delegates.
Traditionally, queries against data are expressed as simple strings without type checking at compile time or intellisense support. Linq offers common syntax for querying any type of data source. We have to references excel namespace to the project. The acronym linq stands for language integrated query. Language integrated query linq, pronounced link is a microsoft. Net languageintegrated query for relational data krzysztof mossakowski. Convert documents to pdf files from command line 2. Net language integrated query linq to objects datasets linq to sql linq to entities linq to xml objects relational xml figure 3. Net linq defines a set of query operators can be used to query, project, and filter data data can be in arrays, enumerables, xml, and databases querying handled by the linq engine results returned as a collection of in memory objects that can be iterated on. Your contribution will go a long way in helping us. An example of creating a new page and adding it to docs sequence of pages page newpg doc.
The following example shows how the three parts of a query operation are expressed in source code. One of the printing methods used are using printing via verbs. It is also possible with linq to entities to change queried data details and committing a batch update easily. Linq support is also provided by third parties for many web services and other database implementations.
In this tutorial, i am going to show how you can import pages from an existing pdf document to another pdf document. Please note that within the linq query and more specifically within the select clause you can create a collection of the same object that is being queried or a new class object or an anonymous type but you can not ask it to execute a method such as mytable. The name of the bookmark xml document that describes the bookmarks to add to the pdf document is bookmarks. Extensibility model supports addingreplacing them query expressionsquery expressions can operate on information sourcescan operate on information sources and apply query operators against them to return. Types of linq the types of linq are mentioned below in brief.
Language integrated query allows native data querying in. Here generally the query ends with group by or select. Type relationships in linq query operations describes how types are preserved andor transformed in the three parts of a linq query operation. Ive added some data for product groups g1 and g2 spread over january and february and ive also added a second output which does exactly the same in linq method syntax. The following code is from an example that shows a couple of different methods to print a microsoft word document to a pdf file. Stack overflow for teams is a private, secure spot for you and your coworkers to find and share information. She covers standard queriessuch as finding overlaps in two datasets and creating hierarchiesas well as complex chained queries. Ive found that it is possible to use dynamic linq using the system. Rights and contracts department 501 boylston street, suite 900 boston. Linq to entities has for these advantages become the standard mechanism for the usage of linq on databases nowadays. I am using a into keyword which is basically a range variable. Lets see an example of linq group by using comprehension query syntax.
Net framework orcas release, and which allows you to model a relational database using. Linq can be used to perform query operations on a variety of data sources such as databases, arrays, lists, xml files, etc. Query syntax and method syntax in linq compares method syntax and query syntax as two ways to express a linq query. In this article, i am showing the use of linq in displaying, sorting, grouping and filtering data. Pdf linq which is the abbreviation of language integrated query. Suppose that you want to read pages from an existing pdf document and display pages in the new pdf document in a table layout as shown below. Taking the boredom out of querying joseph albahari. So, you must know the concept of saving data in a file. Linq, the same data query can be written in a readable colorcoded form like the following one mentioned below that too in a very less time. Syntaxes are much easier than xmldocument and it requires a minimal amount of code. Linq to entities apart from the above, there is also a linq type named plinq which is microsofts parallel linq. Now linq to xml uses xdocument for the same kind of thing. In a hierarchical model, suppose that each customer has its own set of orders, and each order has its own list of products. Windows can go online to look it up automatically, or you can manually select from a list of programs that are installed on your computer.
You will not get database everywhere to save information and your project may require saving information in a txt file, doc file, xls file, pdf files or any other file types. This example is referred to throughout the rest of this topic. All examples are compiled and tested on visual studio. The example uses an integer array as a data source for convenience. Query expressions are written in a declarative query syntax. Linq is extensible that means it is possible to use knowledge of linq to querying new data source types. Linq basicslinq basics query operators can be used against any. A control called pdfrenderer will be available to add. By using query syntax, you can perform filtering, ordering, and grouping operations on data sources with a minimum of code. Dynamic namespace that it is mentioned in scott gus blog but im not sure if can be used for what i need it for. For example, sql is a structured query language used to save and retrieve data.
Linq cheat sheet query syntax lambda syntax filtering var col from o in orders. In this article, i am extracting the data stored in an array. For example, i want to check if any of the resulting objects contain a specific categoryid and if yes, i want to print it. A pdf rendering engine might output this as 2 separate calls, as shown in this pseudocode. Linq offers the facility of joining several data sources in a single query as well as breaking complex problems into a set of short queries easy to debug. If youre looking for a free download links of linq unleashed. You can then query the database using linq, as well as updateinsertdelete data from it. Programmers can easily process database systems, xml documents and programming objects by using linq technology component. Example this is the original script that was tested to convert the example patient record ms office files to pdf on a microsoft windows 10 env. I need to be able to return a list of files that meet some dynamic criteria. Net dataset, xml docs, web service and ms sql server and other databases. However, linq is not limited to a single data domain like the relational model is. Furthermore, you have to learn a different query language for each.
What is the most intriguing fact about linq to entities is that it. For a developer who writes queries, the most visible languageintegrated part of linq is the query expression. Linq to sql is an orm object relational mapping implementation that ships in the. All linq query operations consist of three distinct actions.
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