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collection object not showing properties of stored object?properties of that textbox from the collection object: Dim col as collection set col = new collection col.Add(txt1) col(0).Text = "test" This is not happening in VB.Net. Is there a way to use a collection object in VB2005 this way? Or is there another object I should use that can do this? Actaully, what I am storing in the collection object is a DataTable. I want to do something like this: tblColl.Add(dataset1.tbl1) tblColl.Add(dataset1.tbl2) .... For i As Integer = 0 to tblcoll(j).Rows.Count - 1 .... But I don't Rows after tblColl(0). What should I do to perform this kind of operation with my datatables? Thanks, Rich Nevermind. I forgot:
dim tblColl() As DataTable tblColl = New DataTbl(){ds.tbl1, ds.tbl2, ds.tbl3} Now I have my dropdpwns. Show quoteHide quote "Rich" wrote: > In VB6 I used to be able to add an object like a textbox and see the dropdown > properties of that textbox from the collection object: > > Dim col as collection > set col = new collection > col.Add(txt1) > > col(0).Text = "test" > > This is not happening in VB.Net. Is there a way to use a collection object > in VB2005 this way? Or is there another object I should use that can do > this? Actaully, what I am storing in the collection object is a DataTable. > I want to do something like this: > > tblColl.Add(dataset1.tbl1) > tblColl.Add(dataset1.tbl2) > ... > For i As Integer = 0 to tblcoll(j).Rows.Count - 1 > ... > > But I don't Rows after tblColl(0). What should I do to perform this kind > of operation with my datatables? > > Thanks, > Rich
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"Rich" <R***@discussions.microsoft.com> wrote in message Not sure if you know this, but the DataSet class has a Tables collection news:C96DE849-76E2-4605-BB86-A9129857A9A5@microsoft.com... > Nevermind. I forgot: > > dim tblColl() As DataTable > tblColl = New DataTbl(){ds.tbl1, ds.tbl2, ds.tbl3} > > Now I have my dropdpwns. > > "Rich" wrote: > >> In VB6 I used to be able to add an object like a textbox and see the >> dropdown >> properties of that textbox from the collection object: >> >> Dim col as collection >> set col = new collection >> col.Add(txt1) >> >> col(0).Text = "test" >> >> This is not happening in VB.Net. Is there a way to use a collection >> object >> in VB2005 this way? Or is there another object I should use that can do >> this? Actaully, what I am storing in the collection object is a >> DataTable. >> I want to do something like this: >> >> tblColl.Add(dataset1.tbl1) >> tblColl.Add(dataset1.tbl2) >> ... >> For i As Integer = 0 to tblcoll(j).Rows.Count - 1 >> ... >> >> But I don't Rows after tblColl(0). What should I do to perform this >> kind >> of operation with my datatables? >> >> Thanks, >> Rich already built in. So, try: .... For i As Integer = 0 To dataset1.Tables(j).Rows.Count - 1 ... Next i .... HTH, Mythran Rich,
There is one thing that every regular in this newsgroup tels about the microsoft.visualbasic.namespace they should in that not have included the collection, that one is weird working. Try the arraylist or any other collection or list from system. For the rest, I don't understand your problem (probably it is a cast problem), if nobody else answers, than please rephrase. And than not with the collection but with by instance the arraylist (the most basic one). http://msdn2.microsoft.com/en-us/library/system.collections.aspx I hope this helps, Cor Show quoteHide quote "Rich" <R***@discussions.microsoft.com> schreef in bericht news:740682E3-F13D-4D85-B18B-730D68092E4D@microsoft.com... > In VB6 I used to be able to add an object like a textbox and see the > dropdown > properties of that textbox from the collection object: > > Dim col as collection > set col = new collection > col.Add(txt1) > > col(0).Text = "test" > > This is not happening in VB.Net. Is there a way to use a collection > object > in VB2005 this way? Or is there another object I should use that can do > this? Actaully, what I am storing in the collection object is a > DataTable. > I want to do something like this: > > tblColl.Add(dataset1.tbl1) > tblColl.Add(dataset1.tbl2) > ... > For i As Integer = 0 to tblcoll(j).Rows.Count - 1 > ... > > But I don't Rows after tblColl(0). What should I do to perform this kind > of operation with my datatables? > > Thanks, > Rich Rich wrote:
> In VB6 I used to be able to add an object like a textbox and see the dropdown Sort of, but VB.Net does things a little differently.> properties of that textbox from the collection object: > > Dim col as collection > set col = new collection > col.Add(txt1) > > col(0).Text = "test" > > This is not happening in VB.Net. Is there a way to use a collection object > in VB2005 this way? In VB6, Collections contained Variants so, once you typed as far as a Variant in the your code, the IDE /gave up/ trying to work out what it could give you next but let you type it anyway. Only at /run-time/ did it worry about whether it was valid or not to access, say, a .Text property on whatever object it happened to have at the time. In VB.Net, Variants are dead and buried (and good riddance), being replaced by far tighter variable Type'ing rules at compile time and the [almost complete] removal of this run-time "guesswork" about whether method calls are valid or not. Collections contain Objects (most other types are derived from Object, so they will all "fit" into an Object variable). To be able to do, say, TextBox-y things to an item in a Collection, you have to convince the /compiler/ that it's a valid thing to do. You do this by first ensuring that the thing you've got from the Collection really /is/ the Type you want it to be, then tell the compiler to treat it as such, as in Dim txt1 as New TextBox Dim col as New Collection ' There are better classes for this, ArrayList being the easiest, ' and "Dim .. As New .." is perfectly correct now. col.Add(txt1) ' First check the Type of the item ... If TypeOf col.Item(0) Is TextBox Then ' ... then use it as a TextBox DirectCast( col.Item(0), TextBox ).Text = "test" End If (Some people use CType instead of DirectCast. I prefer this because it only does Type casting and won't try to do anything "clever" (like converting between different data types) for you - CType will. > Or is there another object I should use that can do this? Look in the System.Collections Namespace.> Actaully, what I am storing in the collection object is a DataTable. Odd thing to do - why not leave them in their more normal setting - a DataSet? > I want to do something like this: Same problem. The collection item is of Type Object, and the Object > > tblColl.Add(dataset1.tbl1) > tblColl.Add(dataset1.tbl2) > ... > For i As Integer = 0 to tblcoll(j).Rows.Count - 1 > ... > > But I don't [see?] Rows after tblColl(0). Type doesn't have a "Rows" property (it doesn't have much of anything). To use it /as/ a DataTable, you have to convince the compiler that it is OK to do so, as in For i As Integer = 0 _ To DirectCast( tblcoll(j), DataTable ).Rows.Count - 1 HTH, Phill W. Phill,
I will not say that my answers are always excellent readable (I wished they were). I had to read one sentence of you in this message 5 times, because I thought that you were writing it wrong but could not believe it because of the rest of the answer. Therefore for others, the "this" in the message about the DirectCast and the CType is the DirectCast, than the explanation is completely correct. Don't see this as comment, it was an excellent answer, Cor Show quoteHide quote "Phill W." <p-.-a-.-w-a-r-d@o-p-e-n-.-a-c-.-u-k> schreef in bericht news:eisecg$rfj$1@south.jnrs.ja.net... > Rich wrote: > >> In VB6 I used to be able to add an object like a textbox and see the >> dropdown properties of that textbox from the collection object: >> >> Dim col as collection >> set col = new collection >> col.Add(txt1) >> >> col(0).Text = "test" >> >> This is not happening in VB.Net. Is there a way to use a collection >> object in VB2005 this way? > > Sort of, but VB.Net does things a little differently. > > In VB6, Collections contained Variants so, once you typed as far as a > Variant in the your code, the IDE /gave up/ trying to work out what it > could give you next but let you type it anyway. Only at /run-time/ did it > worry about whether it was valid or not to access, say, a .Text property > on whatever object it happened to have at the time. > > In VB.Net, Variants are dead and buried (and good riddance), being > replaced by far tighter variable Type'ing rules at compile time and the > [almost complete] removal of this run-time "guesswork" about whether > method calls are valid or not. > Collections contain Objects (most other types are derived from Object, so > they will all "fit" into an Object variable). To be able to do, say, > TextBox-y things to an item in a Collection, you have to convince the > /compiler/ that it's a valid thing to do. You do this by first ensuring > that the thing you've got from the Collection really /is/ the Type you > want it to be, then tell the compiler to treat it as such, as in > > Dim txt1 as New TextBox > > Dim col as New Collection > ' There are better classes for this, ArrayList being the easiest, > ' and "Dim .. As New .." is perfectly correct now. > > col.Add(txt1) > > ' First check the Type of the item ... > If TypeOf col.Item(0) Is TextBox Then > ' ... then use it as a TextBox > DirectCast( col.Item(0), TextBox ).Text = "test" > End If > > (Some people use CType instead of DirectCast. I prefer this because it > only does Type casting and won't try to do anything "clever" (like > converting between different data types) for you - CType will. > >> Or is there another object I should use that can do this? > > Look in the System.Collections Namespace. > >> Actaully, what I am storing in the collection object is a DataTable. > > Odd thing to do - why not leave them in their more normal setting - a > DataSet? > >> I want to do something like this: >> >> tblColl.Add(dataset1.tbl1) >> tblColl.Add(dataset1.tbl2) >> ... >> For i As Integer = 0 to tblcoll(j).Rows.Count - 1 >> ... >> >> But I don't [see?] Rows after tblColl(0). > > Same problem. The collection item is of Type Object, and the Object Type > doesn't have a "Rows" property (it doesn't have much of anything). To use > it /as/ a DataTable, you have to convince the compiler that it is OK to do > so, as in > > For i As Integer = 0 _ > To DirectCast( tblcoll(j), DataTable ).Rows.Count - 1 > > HTH, > Phill W. |
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