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Typed Dataset event handling problemfile to handle the RowChanging event. The dataset name is dalCadastro and the datatable is pessoa. The code I wrote to extend the dataset and handle the event is as follows: public partial class dalCadastro { public partial class pessoaDataTable { public override void BeginInit() { base.BeginInit(); this.RowChanging += new DataRowChangeEventHandler(Validate); } void Validate(object sender, DataRowChangeEventArgs e) { throw new Exception("Can not change!"); } } } It compiles OK. But when the page is loaded, the exception I created was thrown. Why if the event is only when a column is changing ? I tried to test if( e.Row.RowState == DataRowState.Modified ), but not works. The state is allways Detached ... Even if I issued the update. I tried test if (e.Action == DataRowAction.Change), but do not work too. I'm using a form view and a object datasource configured to use this typed dataset. All select, insert, delete and update works fine, but the Event handling not. What is the correct form for this type of event handling or what verifications I need to do in the event handler code ? I tried several internet samples, but none work, even compile. An observation, the code was writen with the help of the VS 2005 IDE when i'm was typing the code. What is the solution please ? --- I tried a more strongly typed handling (that is possible in VS 2005) ... but the same behavior continues: public partial class dalCadastro { public partial class pessoaDataTable { public override void BeginInit() { base.BeginInit(); Here-->> this.pessoaRowChanging += new pessoaRowChangeEventHandler(Validate); } void Validate(object sender, -->> Here pessoaRowChangeEvent e) { throw new Exception("Cannot change"); } } } -- Lucas Ponzo Software Engineering Override Software I tried follow a sample in
http://msdn2.microsoft.com/en-us/library/1120xds5.aspx The code was modied as follows: public partial class dalCadastro { public partial class pessoaDataTable { public override void EndInit() { base.EndInit(); pessoaRowChanging += Validate; } void Validate(object sender, pessoaRowChangeEvent e) { throw new Exception("Cannot change"); } } } But the same behavior occurs. On the page load, the exception (coded in the event handler) was thrown !!!! -- Show quoteLucas Ponzo Software Engineering Override Software "Lucas Ponzo" wrote: > > I have a standard typed dataset (.net 2005). And created a separete class > file to handle the RowChanging event. The dataset name is dalCadastro and the > datatable is pessoa. The code I wrote to extend the dataset and handle the > event is as follows: > > public partial class dalCadastro > { > public partial class pessoaDataTable > { > public override void BeginInit() > { > base.BeginInit(); > this.RowChanging += > new DataRowChangeEventHandler(Validate); > } > > void Validate(object sender, DataRowChangeEventArgs e) > { > throw new Exception("Can not change!"); > } > } > } > > It compiles OK. But when the page is loaded, the exception I created was > thrown. Why if the event is only when a column is changing ? > > I tried to test if( e.Row.RowState == DataRowState.Modified ), but not > works. The state is allways Detached ... Even if I issued the update. > > I tried test if (e.Action == DataRowAction.Change), but do not work too. > > I'm using a form view and a object datasource configured to use this typed > dataset. All select, insert, delete and update works fine, but the Event > handling not. > > What is the correct form for this type of event handling or what > verifications I need to do in the event handler code ? > > I tried several internet samples, but none work, even compile. > > An observation, the code was writen with the help of the VS 2005 IDE when > i'm was typing the code. > > What is the solution please ? > > --- I tried a more strongly typed handling (that is possible in VS 2005) ... > but the same behavior continues: > > public partial class dalCadastro > { > public partial class pessoaDataTable > { > public override void BeginInit() > { > base.BeginInit(); > Here-->> this.pessoaRowChanging += new > pessoaRowChangeEventHandler(Validate); > } > > void Validate(object sender, -->> Here pessoaRowChangeEvent e) > { > throw new Exception("Cannot change"); > } > } > } > > -- > Lucas Ponzo > Software Engineering > Override Software I discover the reason, but not the solution. Examining the stack trace I
discovered that the object datasource when call the Select method, the typed dataset class issues AcceptChanges() and CommitRow() ... this fires my event handler. How to handle solve this ? Appears to be a room with no exit. Follow the relevant stack trace : pessoaDataTable.Validate(Object sender, pessoaRowChangeEvent e) in c:\dotNet\SMS\App_Code\Business\bllCadastro.cs:19 pessoaDataTable.OnRowChanged(DataRowChangeEventArgs e) in c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\sms\61162d46\e25f7ec2\App_Code.4-hlcjqb.1.cs:466 System.Data.DataTable.OnRowChanged(DataRowChangeEventArgs args, DataRow eRow, DataRowAction eAction) +87 System.Data.DataTable.CommitRow(DataRow row) +86 System.Data.DataRow.AcceptChanges() +310 System.Data.DataTable.LoadDataRow(Object[] values, Boolean fAcceptChanges) +397 System.Data.ProviderBase.SchemaMapping.LoadDataRow() +167 -- Show quoteLucas Ponzo Software Engineering Override Software "Lucas Ponzo" wrote: > > I tried follow a sample in > http://msdn2.microsoft.com/en-us/library/1120xds5.aspx > > The code was modied as follows: > > public partial class dalCadastro > { > public partial class pessoaDataTable > { > public override void EndInit() > { > base.EndInit(); > pessoaRowChanging += Validate; > } > > void Validate(object sender, pessoaRowChangeEvent e) > { > throw new Exception("Cannot change"); > } > } > } > > But the same behavior occurs. On the page load, the exception (coded in the > event handler) was thrown !!!! > > -- > Lucas Ponzo > Software Engineering > Override Software > > > "Lucas Ponzo" wrote: > > > > > I have a standard typed dataset (.net 2005). And created a separete class > > file to handle the RowChanging event. The dataset name is dalCadastro and the > > datatable is pessoa. The code I wrote to extend the dataset and handle the > > event is as follows: > > > > public partial class dalCadastro > > { > > public partial class pessoaDataTable > > { > > public override void BeginInit() > > { > > base.BeginInit(); > > this.RowChanging += > > new DataRowChangeEventHandler(Validate); > > } > > > > void Validate(object sender, DataRowChangeEventArgs e) > > { > > throw new Exception("Can not change!"); > > } > > } > > } > > > > It compiles OK. But when the page is loaded, the exception I created was > > thrown. Why if the event is only when a column is changing ? > > > > I tried to test if( e.Row.RowState == DataRowState.Modified ), but not > > works. The state is allways Detached ... Even if I issued the update. > > > > I tried test if (e.Action == DataRowAction.Change), but do not work too. > > > > I'm using a form view and a object datasource configured to use this typed > > dataset. All select, insert, delete and update works fine, but the Event > > handling not. > > > > What is the correct form for this type of event handling or what > > verifications I need to do in the event handler code ? > > > > I tried several internet samples, but none work, even compile. > > > > An observation, the code was writen with the help of the VS 2005 IDE when > > i'm was typing the code. > > > > What is the solution please ? > > > > --- I tried a more strongly typed handling (that is possible in VS 2005) ... > > but the same behavior continues: > > > > public partial class dalCadastro > > { > > public partial class pessoaDataTable > > { > > public override void BeginInit() > > { > > base.BeginInit(); > > Here-->> this.pessoaRowChanging += new > > pessoaRowChangeEventHandler(Validate); > > } > > > > void Validate(object sender, -->> Here pessoaRowChangeEvent e) > > { > > throw new Exception("Cannot change"); > > } > > } > > } > > > > -- > > Lucas Ponzo > > Software Engineering > > Override Software I have the same issue. I want to detect row changes in a typed dataset. Everytime the page loads, I get an add and a commit event for every row as it gets loaded. Did you ever find the solution?
EggHeadCafe.com - .NET Developer Portal of Choice http://www.eggheadcafe.com Joel,
Attach event handlers only after dataset/datatable is loaded. -- Show quoteMiha Markic [MVP C#, INETA Country Leader for Slovenia] RightHand .NET consulting & development www.rthand.com Blog: http://cs.rthand.com/blogs/blog_with_righthand/ "Joel Holder" wrote in message news:2006111235759jholder@networklogistic.com... >I have the same issue. I want to detect row changes in a typed dataset. >Everytime the page loads, I get an add and a commit event for every row as >it gets loaded. Did you ever find the solution? > > EggHeadCafe.com - .NET Developer Portal of Choice > http://www.eggheadcafe.com On Sun, 12 Nov 2006 14:46:41 +0100, "Miha Markic [MVP C#]" <miha at rthand com> I hadn't thought of that, Miha. It's a good solution.wrote: >Joel, > >Attach event handlers only after dataset/datatable is loaded. Usually when I don't want things to happen during loads I will declare a private bool named loading in the class and set it to true at the beginning of the form's Load event and then set it to false at the end of the event. Then any vents I don't want to process will have: if(loading) { return; } at the beginning. Good luck with your project, Otis Mukinfus http://www.arltex.com http://www.tomchilders.com Hi Otis,
Show quote "Otis Mukinfus" <ph***@emailaddress.com> wrote in message This is a solution however much slower becuase the event is still handled..news:0ebel2to4ov2b8jqumsscehpqvl8250c3s@4ax.com... > On Sun, 12 Nov 2006 14:46:41 +0100, "Miha Markic [MVP C#]" <miha at rthand > com> > wrote: > >>Joel, >> >>Attach event handlers only after dataset/datatable is loaded. > > I hadn't thought of that, Miha. It's a good solution. > > Usually when I don't want things to happen during loads I will declare a > private > bool named loading in the class and set it to true at the beginning of the > form's Load event and then set it to false at the end of the event. Then > any > vents I don't want to process will have: > > if(loading) > { > return; > } > > at the beginning. -- Miha Markic [MVP C#, INETA Country Leader for Slovenia] RightHand .NET consulting & development www.rthand.com Blog: http://cs.rthand.com/blogs/blog_with_righthand/
Show quote
On Sun, 12 Nov 2006 16:01:11 +0100, "Miha Markic [MVP C#]" <miha at rthand com> You're right, Miha. That's why my next adventure will probably include yourwrote: >Hi Otis, > >"Otis Mukinfus" <ph***@emailaddress.com> wrote in message >news:0ebel2to4ov2b8jqumsscehpqvl8250c3s@4ax.com... >> On Sun, 12 Nov 2006 14:46:41 +0100, "Miha Markic [MVP C#]" <miha at rthand >> com> >> wrote: >> >>>Joel, >>> >>>Attach event handlers only after dataset/datatable is loaded. >> >> I hadn't thought of that, Miha. It's a good solution. >> >> Usually when I don't want things to happen during loads I will declare a >> private >> bool named loading in the class and set it to true at the beginning of the >> form's Load event and then set it to false at the end of the event. Then >> any >> vents I don't want to process will have: >> >> if(loading) >> { >> return; >> } >> >> at the beginning. > >This is a solution however much slower becuase the event is still handled.. solution. Thanks for the tip! Good luck with your project, Otis Mukinfus http://www.arltex.com http://www.tomchilders.com Hi Othis,
But how to do it when the event handler is on another layer of the application ? In this case, in a event handler to being registered in an extended TypedDataSet Class ? -- Show quoteLucas Ponzo ..NET Solutions Architect/Engineer Override Software "Otis Mukinfus" wrote: > On Sun, 12 Nov 2006 14:46:41 +0100, "Miha Markic [MVP C#]" <miha at rthand com> > wrote: > > >Joel, > > > >Attach event handlers only after dataset/datatable is loaded. > > I hadn't thought of that, Miha. It's a good solution. > > Usually when I don't want things to happen during loads I will declare a private > bool named loading in the class and set it to true at the beginning of the > form's Load event and then set it to false at the end of the event. Then any > vents I don't want to process will have: > > if(loading) > { > return; > } > > at the beginning. > > > Good luck with your project, > > Otis Mukinfus > http://www.arltex.com > http://www.tomchilders.com > Hi Miha,
Yes, but in a case that I have the Typed DataSet and I bound it to a ObjectDataSource, and a FormView bouded to this ObjectDataSource in a ASP.NET 2.0 Page ? When the page loads, the fill is called automatically. The corret way (I thynk, and many articles, including Microsoft articles) orient you to do some like this following code, but the e.Action and e.Row.RowState remains the same booth when the page loads and when a Update operation occurs in the FormView. I thynk its a bug, and the workarroud to avoid this are very non-elegant and needs rewok every time I reconfigure the Typed DataSet. public partial class TesteTD { public partial class tab_smsDataTable { public override void EndInit() { base.EndInit(); this.tab_smsRowChanging += new tab_smsRowChangeEventHandler(Validate); } void Validate(object sender, tab_smsRowChangeEvent e) { if (e.Action != DataRowAction.Add && e.Row.RowState != DataRowState.Added) { throw new Exception("Não pode alerar!"); } } } } -- Show quoteLucas Ponzo ..NET Solutions Architect/Engineer Override Software "Miha Markic [MVP C#]" wrote: > Joel, > > Attach event handlers only after dataset/datatable is loaded. > > -- > Miha Markic [MVP C#, INETA Country Leader for Slovenia] > RightHand .NET consulting & development www.rthand.com > Blog: http://cs.rthand.com/blogs/blog_with_righthand/ > > "Joel Holder" wrote in message > news:2006111235759jholder@networklogistic.com... > >I have the same issue. I want to detect row changes in a typed dataset. > >Everytime the page loads, I get an add and a commit event for every row as > >it gets loaded. Did you ever find the solution? > > > > EggHeadCafe.com - .NET Developer Portal of Choice > > http://www.eggheadcafe.com > A friend tell me that it happens because when the page loads, the internal
code for the Typed DataSet calls the Fill method for the datatable, and consequently this makes the rows to be changed. He sugested that I copy DataSet.Designer.cs to another file. Delete the Fill method in the original DataSet.Designer.cs and in the new dataset.cs file, re-write the Fill method and register the event after the adapter's Fill method call. This will avoid the event to be fired when the page lods, because in the normal situation the event is already registered, and when the page loads it is fired. The boring thing about this solution is when you reconfigure you Typed Dataset, you must delete de fill method in the original DatasetDesigner.cs ... you must delete because if not, you will have two Fill methods for the datatable. Deleting, the compiler will consider you version on the other .cs file, that implement the datatable's Fill method diferently. I thynked that the correct thing was only create a separate file and write code to register for the event using the "partial" keyword. The only work more where to test the e.Action and e.Row.State ... I thinked that the following code resolved my problem, but not. Both in the page load, as in the Update action in my form view, these values are the same. Look ... its a standard code (TesteTD is the name of the typed dataset and tab_smsDataTable is the name of the datatable i'm subscribing to the event. The result of this code was: the page loads OK, but when I update, the test exception is not thrown ... because the event argument values are allways the same. public partial class TesteTD { public partial class tab_smsDataTable { public override void EndInit() { base.EndInit(); this.tab_smsRowChanging += new tab_smsRowChangeEventHandler(Validate); } void Validate(object sender, tab_smsRowChangeEvent e) { if (e.Action != DataRowAction.Add && e.Row.RowState != DataRowState.Added) { throw new Exception("Cannot Change!"); } } } } I'm yet investigating a more elegant solution ... I'm doing somes tests and working with this guy from Microsoft. And any good news be sure I'll reply to you. Best Regards, -- Show quoteLucas Ponzo ..NET Solutions Architect/Engineer Override Software "Joel Holder" wrote: > I have the same issue. I want to detect row changes in a typed dataset. Everytime the page loads, I get an add and a commit event for every row as it gets loaded. Did you ever find the solution? > > EggHeadCafe.com - .NET Developer Portal of Choice > http://www.eggheadcafe.com > Hi Joel,
Why we cannot control when the Row is really Changing or Changed, (or in other states) using the event handler argument. The reason is that it is ASP.net Project. In Winform, the DataTable will be stored in memory after we create it. When DataTable has been changed, Winform can compare it with the DataTable in memory. So we can know which row has been changed. But in ASP.net, there is no memory to store this DataTable. The DataTable will be generated everytime if there is a http request. In our case, the OjectDataSource will create the table when there is a Http Request, then bind it to FormView. The most important thing is that the behavior after we click "Update" in "Edit Mode". It is something different as we think before: The OjectDataSource create a table and change the row then update to Database. But the actual behavior is that ObjectDataSource will update the row directly to Database and then create a new DataTable from the database. There is no DataTable in memory when we click "Update" button, so we cannot catch the DataTable's "RowChanging" event. There is always a new DataTable created by ObjectDataSource. There are always the "add" and "Commit" Event. For these reasons, I'm afraid we cannot use "RowChanging" event. It will not work as we expect in ASP.net, even through it work fine in WinForm Project. We should have to do some code in FormViewe rather than in Typed Dataset. For example: Add follow code in Form Viewe Item Updating Event. protected void FormView1_ItemUpdating1(object sender, FormViewUpdateEventArgs e) { Response.Write("can not be edit"); e.Cancel = true; } It is some restriction from ASP.net not ADO.net. But I have some ideas: 1) Create a wrapper bussiness class to use in the object datasource and in the update method do the validations. 2) Create a derived class that caches the datatable and work like in WinForms ... it's a more complex task. Best Regards, -- Show quoteLucas Ponzo ..NET Solutions Architect/Engineer Override Software "Joel Holder" wrote: > I have the same issue. I want to detect row changes in a typed dataset. Everytime the page loads, I get an add and a commit event for every row as it gets loaded. Did you ever find the solution? > > EggHeadCafe.com - .NET Developer Portal of Choice > http://www.eggheadcafe.com >  |
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