Check if instance is of a type

Question

Using this to check if c is an instance of TForm    c GetType   Name CompareTo  TForm      0   Is there a more type safe way to do it besides using a string as a param to CompareTo

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Or   c getType      typeOf TForm

User · Answer

As others have mentioned  the  is  keyword   However  if you re going to later cast it to that type  eg   TForm t    TForm c    Then you should use the  as  keyword   e g   TForm t   c as TForm   Then you can check   if t    null        put TForm specific stuff here     Don t combine as with is because it s a duplicate check

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A little more compact than the other answers if you want to use c as a TForm   if c is TForm form       form DoStuff

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bool isValid   c GetType      typeof TForm    true   false    or simpler  bool isValid   c GetType      typeof TForm

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The different answers here have two different meanings   If you want to check whether an instance is of an exact type then  if  c GetType      typeof TForm     is the way to go   If you want to know whether c is an instance of TForm or a subclass then use is as   if  c is TForm    or  TForm form   c as TForm  if  form    null    It s worth being clear in your mind about which of these behaviour you actually want

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Try the following  if  c is TForm

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if c is TFrom          Do Stuff     or if you plan on using c as a TForm  use the following example   var tForm   c as TForm  if tForm    null          c is of type TForm     The second example only needs to check to see if c is of type TForm once  Whereis if you check if see if c is of type TForm then cast it  the CLR undergoes an extra check  Here is a reference   Edit  Stolen from Jon Skeet  If you want to make sure c is of TForm and not any class inheriting from TForm  then use   if c GetType      typeof TForm           Do stuff cause c is of type TForm and nothing else

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Yes  the  is  keyword   if  c is TForm                See details on MSDN  http   msdn microsoft com en-us library scekt9xw VS 80  aspx     Checks if an object is compatible with a given type  For example  it can be determined if an object is compatible with the string type like this

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Also  somewhat in the same vein  Type IsAssignableFrom Type c        True if c and the current Type represent the same type  or if the   current Type is in the inheritance hierarchy of c  or if the current   Type is an interface that c implements  or if c is a generic type   parameter and the current Type represents one of the constraints of c     From here  http   msdn microsoft com en-us library system type isassignablefrom aspx

[c#] Check if instance is of a type

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