what is this c# syntax?

[Davíð Þórisson]

hi
I'm new to c# and although having read 2 tutorials I cannot find what the
parenthesis in these 2 example situations mean;

1) string strKeyValue = (string)sampleC onfig["Title"];
2) class myParentPage = (default_aspx) this.Page;

(default_aspx is the class name for my parent Page)

[Bob Grommes]

Roy,

Well then perhaps I should rephrase it this way:

"To successfully cast any reference type A to B, A and B must either have an
inheritance relationship with one another, or A must have an appropriate
user-defined type conversion operator defined for type B."

Thanks for the nice refinement.

--Bob

"Roy Fine" <rl****@twt.obf uscate.net> wrote in message
news:ea******** ******@TK2MSFTN GP11.phx.gbl...

"Bob Grommes" <bo*@bobgrommes .com> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. ..

Simple value types have conversion rules that are defined by the C#

language

specification.

To successfully cast any reference type A to B, A and B must have an
inheritance relationship with one another.

not exactly true - what about the implicit conversion operator.

Consider the following in which there is absolutely no inheritance
relationship between MyString and YourString - yet the cast works as
defined
:

regards
roy fine
/* *************** *** */
public void Test(){
YourString a = new YourString("goo dbye");
MyString b = (MyString)a;
}

/* *************** *** */
class MyString{
string val;
public MyString(string t){val=t;}
}

/* *************** *** */
class YourString{
string val;
public YourString(stri ng t){val=t;}
public static implicit operator MyString (YourString t){
return new MyString("Hello ");
}
}

[Roy Fine]

bob, well done.

rlf

"Bob Grommes" <bo*@bobgrommes .com> wrote in message
news:%2******** **********@TK2M SFTNGP11.phx.gb l...

Roy,

Well then perhaps I should rephrase it this way:

"To successfully cast any reference type A to B, A and B must either have an inheritance relationship with one another, or A must have an appropriate
user-defined type conversion operator defined for type B."

Thanks for the nice refinement.

--Bob

"Roy Fine" <rl****@twt.obf uscate.net> wrote in message
news:ea******** ******@TK2MSFTN GP11.phx.gbl...

"Bob Grommes" <bo*@bobgrommes .com> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. ..

Simple value types have conversion rules that are defined by the C#

language

specification.

To successfully cast any reference type A to B, A and B must have an
inheritance relationship with one another.

not exactly true - what about the implicit conversion operator.

Consider the following in which there is absolutely no inheritance
relationship between MyString and YourString - yet the cast works as
defined
:

regards
roy fine
/* *************** *** */
public void Test(){
YourString a = new YourString("goo dbye");
MyString b = (MyString)a;
}

/* *************** *** */
class MyString{
string val;
public MyString(string t){val=t;}
}

/* *************** *** */
class YourString{
string val;
public YourString(stri ng t){val=t;}
public static implicit operator MyString (YourString t){
return new MyString("Hello ");
}
}