Why var is used before linq query

Question

Afzaal Ahmad Zeeshan · Answer

Actually it is not user it used to simplify the pain of type matching. You can write the query as var rows = from obj in objCollection where obj.Member == condition select obj; But actually what you miss is that var is a call to compiler to identify the type of the rows object itself. You don't have to specify anything at all. It is actually an Anonymous object and is Enumerable type. var just tells the compiler to determine a type itself and assign it to rows; otherwise you would personally have to tell a type something like List or something similar to this one. This type check happens at compile-time and the object is assigned that type when compilation takes place.

Manoj Bhoir · Answer

Hi var is an implicitly typed local variable so the type is implied by the compiler based on the value it is assigned . LINQ is used on collection of item or records and while iterating on collection items each item datatype type might me different so to avoid datatype conversion issue var keyword is used to store result set.

Rajeesh Menoth · Answer

Hi It may be because LINQ is used on collection of item or records and while iterating on collection items each item datatype type might me different so avoid datatype conversion issue var keyword is used to store result set.

Govinda Rajulu Yemineni · Answer

Hi var keyword is an implicit way of defining Datatypes.Implicit means indirect way of defining variable types. why we use var keyword in linq query is some times we don't know what type of value we get as a result so to handle that we use var keyword. for more clarification refer the following URL http://www.dotnetfunda.com/articles/show/1567/what-is-the-use-of-var-keyword-in-csharp

Isha Malhotra · Answer

hi var is basically implicit type. we need not to perform type casting while using var. and there is no performance issues while working with var. this is the reason we use var in most of the queries in linq. apart from this sometimes we have situation in linq when we don't have any type to hold for example if we perform grouping or joining in linq then return type is anonymous then var is the best option.

Sakthikumar Thanavel · Answer

It is mainly used for avoiding the type casting problem.

Jignesh Trivedi · Answer

Hi This is not necessary..... The var keyword was introduced in C# 3.0. It is an implicit type and the type is determined by the C# compiler. There is no performance penalty when using var. The C# compiler assigns types to the variable when it assigns the value. It makes programs shorter and easier to read. In short the var keyword is an implicit way of defining data types. It is an indirect way of defining the variable type. The var keyword defines the data type statically (at compile time) and not at runtime. also some time we use it with LINQ and anonymous types that help us reduce the code (reduce effort to create a new class). hope this will help you.