find out if an instance of type type (indirectly) derives from another type

[bonk]

When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstance == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFro mAnotherType" the above evaluates to false..

myTypeInstance. BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

Di dyou try Type.IsSubClass Of ()

--
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation
"bonk" <sc************ ******@gmx.dewr ote in message
news:11******** *************@m 7g2000cwm.googl egroups.com...

When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstance == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFro mAnotherType" the above evaluates to false..

myTypeInstance. BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

[David Anton]

Try:
myTypeInstance is AnotherType
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
Instant C++: C#/VB to C++ converter
C# Code Metrics: Quick metrics for C#
"bonk" wrote:

When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstance == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFro mAnotherType" the above evaluates to false..

myTypeInstance. BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

[Nicholas Paldino [.NET/C# MVP]]

The easiest way (although not the most correct way to do this) would be
to call IsAssignableFro m, like so:

typeof(AnotherT ype).IsAssignab leFrom(myTypeIn stance);

If AnotherType derives from myTypeInstance, then this will return true.
However, IsAssignableFro m does a lot more than just check the inheritance
chain, it checks interfaces, generic types, etc, etc.

A better solution is this:

static bool TypeDerivesFrom (Type base, Type derived)
{
// Removed checking against null for clarity.

// An easy assumption, not necessarily needed.
if (base == typeof(object))
{
// Return true.
return true;
}

// Compare while true.
do while (derived != null)
{
// If the base class is equal to the derived class, then
// return true.
if (base == derived)
{
// Get out.
return true;
}

// Set the derived class equal it's base type.
derived = derived.BaseTyp e;
}

// The type does not derive from another type.
return false;
}

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"bonk" <sc************ ******@gmx.dewr ote in message
news:11******** *************@m 7g2000cwm.googl egroups.com...

When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstance == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFro mAnotherType" the above evaluates to false..

myTypeInstance. BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

[David Anton]

Wow - are you sure you're not just rewriting the "is" operator?
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
Instant C++: C#/VB to C++ converter
C# Code Metrics: Quick metrics for C#
"Nicholas Paldino [.NET/C# MVP]" wrote:

The easiest way (although not the most correct way to do this) would be
to call IsAssignableFro m, like so:

typeof(AnotherT ype).IsAssignab leFrom(myTypeIn stance);

If AnotherType derives from myTypeInstance, then this will return true.
However, IsAssignableFro m does a lot more than just check the inheritance
chain, it checks interfaces, generic types, etc, etc.

A better solution is this:

static bool TypeDerivesFrom (Type base, Type derived)
{
// Removed checking against null for clarity.

// An easy assumption, not necessarily needed.
if (base == typeof(object))
{
// Return true.
return true;
}

// Compare while true.
do while (derived != null)
{
// If the base class is equal to the derived class, then
// return true.
if (base == derived)
{
// Get out.
return true;
}

// Set the derived class equal it's base type.
derived = derived.BaseTyp e;
}

// The type does not derive from another type.
return false;
}

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"bonk" <sc************ ******@gmx.dewr ote in message
news:11******** *************@m 7g2000cwm.googl egroups.com...

When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstance == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFro mAnotherType" the above evaluates to false..

myTypeInstance. BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

[Nicholas Paldino [.NET/C# MVP]]

David,

Yeah, I realized that was exactly what I was doing.

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"David Anton" <Da********@dis cussions.micros oft.comwrote in message
news:87******** *************** ***********@mic rosoft.com...

Wow - are you sure you're not just rewriting the "is" operator?
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
Instant C++: C#/VB to C++ converter
C# Code Metrics: Quick metrics for C#
"Nicholas Paldino [.NET/C# MVP]" wrote:

> The easiest way (although not the most correct way to do this) would
be
to call IsAssignableFro m, like so:

typeof(Another Type).IsAssigna bleFrom(myTypeI nstance);

If AnotherType derives from myTypeInstance, then this will return
true.
However, IsAssignableFro m does a lot more than just check the inheritance
chain, it checks interfaces, generic types, etc, etc.

A better solution is this:

static bool TypeDerivesFrom (Type base, Type derived)
{
// Removed checking against null for clarity.

// An easy assumption, not necessarily needed.
if (base == typeof(object))
{
// Return true.
return true;
}

// Compare while true.
do while (derived != null)
{
// If the base class is equal to the derived class, then
// return true.
if (base == derived)
{
// Get out.
return true;
}

// Set the derived class equal it's base type.
derived = derived.BaseTyp e;
}

// The type does not derive from another type.
return false;
}

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"bonk" <sc************ ******@gmx.dewr ote in message
news:11******* **************@ m7g2000cwm.goog legroups.com...

When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstance == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFro mAnotherType" the above evaluates to false..

myTypeInstance. BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

[Mythran]

"Nicholas Paldino [.NET/C# MVP]" <mv*@spam.guard .caspershouse.c omwrote in
message news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

David,

Yeah, I realized that was exactly what I was doing.

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"David Anton" <Da********@dis cussions.micros oft.comwrote in message
news:87******** *************** ***********@mic rosoft.com...

>Wow - are you sure you're not just rewriting the "is" operator?
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
Instant C++: C#/VB to C++ converter
C# Code Metrics: Quick metrics for C#
"Nicholas Paldino [.NET/C# MVP]" wrote:

>> The easiest way (although not the most correct way to do this) would
be
to call IsAssignableFro m, like so:

typeof(Anothe rType).IsAssign ableFrom(myType Instance);

If AnotherType derives from myTypeInstance, then this will return
true.
However, IsAssignableFro m does a lot more than just check the
inheritance
chain, it checks interfaces, generic types, etc, etc.

A better solution is this:

static bool TypeDerivesFrom (Type base, Type derived)
{
// Removed checking against null for clarity.

// An easy assumption, not necessarily needed.
if (base == typeof(object))
{
// Return true.
return true;
}

// Compare while true.
do while (derived != null)
{
// If the base class is equal to the derived class, then
// return true.
if (base == derived)
{
// Get out.
return true;
}

// Set the derived class equal it's base type.
derived = derived.BaseTyp e;
}

// The type does not derive from another type.
return false;
}

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"bonk" <sc************ ******@gmx.dewr ote in message
news:11****** *************** @m7g2000cwm.goo glegroups.com.. .
When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstan ce == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFr omAnotherType" the above evaluates to false..

myTypeInstance .BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

lol exactly what I was doing on another thread :P I was using reflection
instead of the "is" operator heh.

must be a virus floating around affecting us...

Mythran

[David Anton]

I'm a lazy programmer - sometimes that pays off, sometimes it doesn't ;)
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
Instant C++: C#/VB to C++ converter
C# Code Metrics: Quick metrics for C#
"Nicholas Paldino [.NET/C# MVP]" wrote:

David,

Yeah, I realized that was exactly what I was doing.

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"David Anton" <Da********@dis cussions.micros oft.comwrote in message
news:87******** *************** ***********@mic rosoft.com...

Wow - are you sure you're not just rewriting the "is" operator?
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
Instant C++: C#/VB to C++ converter
C# Code Metrics: Quick metrics for C#
"Nicholas Paldino [.NET/C# MVP]" wrote:

The easiest way (although not the most correct way to do this) would
be
to call IsAssignableFro m, like so:

typeof(AnotherT ype).IsAssignab leFrom(myTypeIn stance);

If AnotherType derives from myTypeInstance, then this will return
true.
However, IsAssignableFro m does a lot more than just check the inheritance
chain, it checks interfaces, generic types, etc, etc.

A better solution is this:

static bool TypeDerivesFrom (Type base, Type derived)
{
// Removed checking against null for clarity.

// An easy assumption, not necessarily needed.
if (base == typeof(object))
{
// Return true.
return true;
}

// Compare while true.
do while (derived != null)
{
// If the base class is equal to the derived class, then
// return true.
if (base == derived)
{
// Get out.
return true;
}

// Set the derived class equal it's base type.
derived = derived.BaseTyp e;
}

// The type does not derive from another type.
return false;
}

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"bonk" <sc************ ******@gmx.dewr ote in message
news:11******** *************@m 7g2000cwm.googl egroups.com...
When I have an instance of an object wich is of type System.Type, how
can I find out if it directly or indirecly derives from another type?

myTypeInstance == typeof(AnotherT ype)

only seems to check if they are ultimately the same type (at the very
bottom of the inheritance hirarchy) but in case myTypeInstance is
"TypeDerivedFro mAnotherType" the above evaluates to false..

myTypeInstance. BaseType == typeof(AnotherT ype)

does the same, only for the direct base class.

[bonk]

David Anton schrieb:

Try:
myTypeInstance is AnotherType
--

This will always evaluate to false since myTypeInstance is always of
type System.Type (see my original post) and AnotherType is not.