hey all,

this is what i thought would make sense to me but got the infamous "Object
not instantiated" error:

DataTable dt;
dt = mySprocDt;
DataTableCollection dtColl = null;
dtColl.Add(dt);

instead i had to do this to make it work:


DataSet ds = new DataSet( );
DataTableCollection dtColl = null;
DataTable dt = null;
dt = mySprocDt;
ds.Tables.Add(dt);
dtColl = ds.Tables;

can someone please explain why the first one didn't work?

thanks,
rodchar

rodchar,

Well, your dtColl variable is null, and you tried to call a method on
it. You have to assign to the variable if you are going to call a method on
it.

Also, the first section of code shouldn't compile, as you should need to
have assigned something to dt in the declaration. I assumed you had
something like:

DataTable dt = null;

Or:

DataTable dt = mySprocDt;

--
- Nicholas Paldino [.NET/C# MVP]
- (E-Mail Removed)


"rodchar" <(E-Mail Removed)> wrote in message
news:6EC4230B-C706-4552-8E7D-(E-Mail Removed)...
> hey all,
>
> this is what i thought would make sense to me but got the infamous "Object
> not instantiated" error:
>
> DataTable dt;
> dt = mySprocDt;
> DataTableCollection dtColl = null;
> dtColl.Add(dt);
>
> instead i had to do this to make it work:
>
>
> DataSet ds = new DataSet( );
> DataTableCollection dtColl = null;
> DataTable dt = null;
> dt = mySprocDt;
> ds.Tables.Add(dt);
> dtColl = ds.Tables;
>
> can someone please explain why the first one didn't work?
>
> thanks,
> rodchar

i tried:
DataTableCollection dtColl = new DataTableCollection( )
but that didn't work, how would i instantiate it?

"Nicholas Paldino [.NET/C# MVP]" wrote:

> rodchar,
>
> Well, your dtColl variable is null, and you tried to call a method on
> it. You have to assign to the variable if you are going to call a method on
> it.
>
> Also, the first section of code shouldn't compile, as you should need to
> have assigned something to dt in the declaration. I assumed you had
> something like:
>
> DataTable dt = null;
>
> Or:
>
> DataTable dt = mySprocDt;
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - (E-Mail Removed)
>
>
> "rodchar" <(E-Mail Removed)> wrote in message
> news:6EC4230B-C706-4552-8E7D-(E-Mail Removed)...
> > hey all,
> >
> > this is what i thought would make sense to me but got the infamous "Object
> > not instantiated" error:
> >
> > DataTable dt;
> > dt = mySprocDt;
> > DataTableCollection dtColl = null;
> > dtColl.Add(dt);
> >
> > instead i had to do this to make it work:
> >
> >
> > DataSet ds = new DataSet( );
> > DataTableCollection dtColl = null;
> > DataTable dt = null;
> > dt = mySprocDt;
> > ds.Tables.Add(dt);
> > dtColl = ds.Tables;
> >
> > can someone please explain why the first one didn't work?
> >
> > thanks,
> > rodchar
>
>
>

Well, what are you trying to create this list for? If you just want a
list of DataTable instances, then why not use List<DataTable>? The
DataTableCollection is tied to the DataSet and it's constructor is
internal/private to System.Data, so you won't be able to instantiate it
directly.

--
- Nicholas Paldino [.NET/C# MVP]
- (E-Mail Removed)

"rodchar" <(E-Mail Removed)> wrote in message
news643AB46-7786-4002-B0CB-(E-Mail Removed)...
>i tried:
> DataTableCollection dtColl = new DataTableCollection( )
> but that didn't work, how would i instantiate it?
>
> "Nicholas Paldino [.NET/C# MVP]" wrote:
>
>> rodchar,
>>
>> Well, your dtColl variable is null, and you tried to call a method on
>> it. You have to assign to the variable if you are going to call a method
>> on
>> it.
>>
>> Also, the first section of code shouldn't compile, as you should need
>> to
>> have assigned something to dt in the declaration. I assumed you had
>> something like:
>>
>> DataTable dt = null;
>>
>> Or:
>>
>> DataTable dt = mySprocDt;
>>
>> --
>> - Nicholas Paldino [.NET/C# MVP]
>> - (E-Mail Removed)
>>
>>
>> "rodchar" <(E-Mail Removed)> wrote in message
>> news:6EC4230B-C706-4552-8E7D-(E-Mail Removed)...
>> > hey all,
>> >
>> > this is what i thought would make sense to me but got the infamous
>> > "Object
>> > not instantiated" error:
>> >
>> > DataTable dt;
>> > dt = mySprocDt;
>> > DataTableCollection dtColl = null;
>> > dtColl.Add(dt);
>> >
>> > instead i had to do this to make it work:
>> >
>> >
>> > DataSet ds = new DataSet( );
>> > DataTableCollection dtColl = null;
>> > DataTable dt = null;
>> > dt = mySprocDt;
>> > ds.Tables.Add(dt);
>> > dtColl = ds.Tables;
>> >
>> > can someone please explain why the first one didn't work?
>> >
>> > thanks,
>> > rodchar
>>
>>
>>

Thanks Nicholas this last reply gave me insight. i didn't know that the
DataTableCollection was tied to the DataSet. I also haven't worked with
generics before so I don't know what List<DataTable> but I'll definitely try
to do some reading up it.
thanks again,
rod.

"Nicholas Paldino [.NET/C# MVP]" wrote:

> Well, what are you trying to create this list for? If you just want a
> list of DataTable instances, then why not use List<DataTable>? The
> DataTableCollection is tied to the DataSet and it's constructor is
> internal/private to System.Data, so you won't be able to instantiate it
> directly.
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - (E-Mail Removed)
>
> "rodchar" <(E-Mail Removed)> wrote in message
> news643AB46-7786-4002-B0CB-(E-Mail Removed)...
> >i tried:
> > DataTableCollection dtColl = new DataTableCollection( )
> > but that didn't work, how would i instantiate it?
> >
> > "Nicholas Paldino [.NET/C# MVP]" wrote:
> >
> >> rodchar,
> >>
> >> Well, your dtColl variable is null, and you tried to call a method on
> >> it. You have to assign to the variable if you are going to call a method
> >> on
> >> it.
> >>
> >> Also, the first section of code shouldn't compile, as you should need
> >> to
> >> have assigned something to dt in the declaration. I assumed you had
> >> something like:
> >>
> >> DataTable dt = null;
> >>
> >> Or:
> >>
> >> DataTable dt = mySprocDt;
> >>
> >> --
> >> - Nicholas Paldino [.NET/C# MVP]
> >> - (E-Mail Removed)
> >>
> >>
> >> "rodchar" <(E-Mail Removed)> wrote in message
> >> news:6EC4230B-C706-4552-8E7D-(E-Mail Removed)...
> >> > hey all,
> >> >
> >> > this is what i thought would make sense to me but got the infamous
> >> > "Object
> >> > not instantiated" error:
> >> >
> >> > DataTable dt;
> >> > dt = mySprocDt;
> >> > DataTableCollection dtColl = null;
> >> > dtColl.Add(dt);
> >> >
> >> > instead i had to do this to make it work:
> >> >
> >> >
> >> > DataSet ds = new DataSet( );
> >> > DataTableCollection dtColl = null;
> >> > DataTable dt = null;
> >> > dt = mySprocDt;
> >> > ds.Tables.Add(dt);
> >> > dtColl = ds.Tables;
> >> >
> >> > can someone please explain why the first one didn't work?
> >> >
> >> > thanks,
> >> > rodchar
> >>
> >>
> >>
>
>
>