Type Checking

is Operator

The is operator checks if the run-time type of an expression result is compatible with a given type.
The is operator doesn't consider user-defined conversions.
The Is Operator only returns a boolean value
It can be useful when you want to determine the type but not necessarily cast
Beginning with C# 7.0, the is operator also tests an expression result against a pattern.

Checks if an object is compatible with a given type and always returns a boolean value
An is expression evaluates to true if the provided expression is non-null, and the provided object can be cast to the provided type without causing an exception to be thrown.
You can use the Is operator to test whether a cast can be made successfully
The is operator cannot be overloaded.
If you know the specific base class, then just use the is keyword:
This is a cast parameter ?

string myobject = ""; 

if (myobject is string) 
{ 
} 
if (myobject is int) 
{ 
} 
if (myobject is class1) 
{ 
} 

Note that the is operator only considers reference conversions, boxing conversions, and unboxing conversions. Other conversions, such as user-defined conversions, are not considered.
You can use the Is and As operators to test whether a cast can be made successfully.

class Dog : Animal {} 

void UseIsOperator(Animal a) 
if (a is Dog) 
{ 
} 

The equivalent in VB.Net is the Is Operator.

typeof Operator

The typeof operator in C# on the other hand returns an instance of the System.Type class containing type declarations of the type you pass to it.

Type t = typeof(string); 

This operator returns an instance of the System.Type class containing type declarations of the type you pass to it.

System.Type type = typeof(int); 

The typeof operator cannot be overloaded.
The equivalent in VB.Net is the GetType Operator
There is a TypeOf Operator in VB.Net but it has a different meaning - which is extremely confusing.

object.GetType()

Also called GetType Method
Also called the GetType Method
This method operators on an object instance.
System.Type.GetType("System.Int32")

if (control.GetType().Name.Equals("TreeView")) 
{ } 

switch (myobject.GetType().ToString()) 
{ 
   case "" : break; 

} 

object.GetType()            // System.Int32 
object.GetType().Name       // Int32 

GetType().Name()
GetType().FullName
The object must be instantiated

This method is also available in VB.Net

Dim sVariable As String 
Dim oType As Type = sVariable.GetType() 

The equivalent in VB.Net is the TypeName function.