Table of difference
var | dynamic |
Introduced in C# 3.0
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Introduced in C# 4.0
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Statically typed – This means the type of variable declared is decided by the compiler at compile time.
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Dynamically typed - This means the type of variable declared is decided by the compiler at runtime time.
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Need to initialize at the time of declaration.
e.g.,
var str=”I am a string”;
Looking at the value assigned to the variable
str , the compiler will treat the variable str as string. |
No need to initialize at the time of declaration.
e.g.,
dynamic str; str=”I am a string”; //Works fine and compilesstr=2; //Works fine and compiles |
Errors are caught at compile time.
Since the compiler knows about the type and the methods and properties of the type at the compile time itself
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Errors are caught at runtime
Since the compiler comes to about the type and the methods and properties of the type at the run time.
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Visual Studio shows intellisense since the type of variable assigned is known to compiler.
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Intellisense is not available since the type and its related methods and properties can be known at run time only
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e.g.,
var obj1;
will throw a compile error since the variable is not initialized. The compiler needs that this variable should be initialized so that it can infer a type from the value.
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e.g.,
dynamic obj1;
will compile;
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e.g.
var obj1=1;
will compile
var obj1=” I am a string”; will throw error since the compiler has already decided that the type of obj1 is System.Int32 when the value 1 was assigned to it. Now assigning a string value to it violates the type safety. |
e.g.
dynamic obj1=1;
will compile and run
dynamic obj1=” I am a string”;
will compile and run since the compiler creates the type for obj1 as System.Int32 and then recreates the type as string when the value “I am a string” was assigned to it.
This code will work fine.
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