Enum Flags comparison

[Christian.Wall]

Hello,

I've got the following enum:

[Flags]
public enum MyStates
{
None = 0
Saved = 1
New = 2
Changed = 4
Deleted = 8
Moved = 16
}

....

Now I create two variables:

MyStates aValue = MyStates.Changed | MyStates.Moved | MyStates.New
MyStates bValue = MyStates.Changed | MyStates.New

Now i want to check if the values in bValue included in aValue (this
must be true)

But if i create a variable, let's call her cValue:
MyStates cValue = MyStates.Changed | MyStates.Saved

In this case cValue is not included in aValue... But my If statement
returns 1 when I compare aValue and cValue:

if ( (IstWert & SollWert) 0)
{
DoSomeThing();
}

Can somebody tell me, how to solve this problem?

Thanks, Chris

[Chris]

Oh, my mistake...
Solved it... It's tooearly ;-)
Ch************@gmx-topmail.de schrieb:

Hello,

I've got the following enum:

[Flags]
public enum MyStates
{
None = 0
Saved = 1
New = 2
Changed = 4
Deleted = 8
Moved = 16
}

...

Now I create two variables:

MyStates aValue = MyStates.Changed | MyStates.Moved | MyStates.New
MyStates bValue = MyStates.Changed | MyStates.New

Now i want to check if the values in bValue included in aValue (this
must be true)

But if i create a variable, let's call her cValue:
MyStates cValue = MyStates.Changed | MyStates.Saved

In this case cValue is not included in aValue... But my If statement
returns 1 when I compare aValue and cValue:

if ( (IstWert & SollWert) 0)
{
DoSomeThing();
}

Can somebody tell me, how to solve this problem?

Thanks, Chris

[Chris]

Oh, my mistake...
Solved it... It's too early ;-)
Ch************@gmx-topmail.de schrieb:

Hello,

I've got the following enum:

[Flags]
public enum MyStates
{
None = 0
Saved = 1
New = 2
Changed = 4
Deleted = 8
Moved = 16
}

...

Now I create two variables:

MyStates aValue = MyStates.Changed | MyStates.Moved | MyStates.New
MyStates bValue = MyStates.Changed | MyStates.New

Now i want to check if the values in bValue included in aValue (this
must be true)

But if i create a variable, let's call her cValue:
MyStates cValue = MyStates.Changed | MyStates.Saved

In this case cValue is not included in aValue... But my If statement
returns 1 when I compare aValue and cValue:

if ( (IstWert & SollWert) 0)
{
DoSomeThing();
}

Can somebody tell me, how to solve this problem?

Thanks, Chris

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

Hi,

You should not include a value for 0 , if you want to check for it , how do
you know if it was None ?
--
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

<Ch************@gmx-topmail.dewrote in message
news:11*********************@75g2000cwc.googlegrou ps.com...

Hello,

I've got the following enum:

[Flags]
public enum MyStates
{
None = 0
Saved = 1
New = 2
Changed = 4
Deleted = 8
Moved = 16
}

...

Now I create two variables:

MyStates aValue = MyStates.Changed | MyStates.Moved | MyStates.New
MyStates bValue = MyStates.Changed | MyStates.New

Now i want to check if the values in bValue included in aValue (this
must be true)

But if i create a variable, let's call her cValue:
MyStates cValue = MyStates.Changed | MyStates.Saved

In this case cValue is not included in aValue... But my If statement
returns 1 when I compare aValue and cValue:

if ( (IstWert & SollWert) 0)
{
DoSomeThing();
}

Can somebody tell me, how to solve this problem?

Thanks, Chris

[Michael Bray]

"Ignacio Machin \( .NET/ C# MVP \)" <ignacio.machin AT dot.state.fl.us>
wrote in news:OJ**************@TK2MSFTNGP04.phx.gbl:

You should not include a value for 0 , if you want to check for it ,
how do you know if it was None ?

I disagree... including a value for 0 is quite useful.

You can check for it very simply:

MyStates state = MyStates.None;
if (state == MyStates.None) { ... }

Now obviously, this isn't the general way you would check for the non-zero
flags, which I usually do like this (is there a better way??):

if ((state & MyStates.Saved) == MyStates.Saved) { ... }

As for the OP question, Chris, you shouldn't check if the result is 0,
you should check one of:

if (aValue & cValue == aValue) - then aValue is a subset of cValue
if (aValue & cValue == cValue) - then cValue is a subset of aValue

if either one doesn't evaluate, but the result 0, then it means that they
have some common elements, but some different elements as well (this is the
case you are seeing currently.)

-mdb