Multiple data soruces

[Randy Kennison]

Using the grouping grid and CollectionBase datasources, is it possible to display a parent child type relationship as it is with DataSets? I''d be using a DataSet, except the performance is terrible at best. In any event, Class A has say 2 Col''s, A and B. Col B has 2 col''s, A and C. ( The A''s from each being the same data, Class A will hold a single record for each A, while class B will hold multiple records for each A value.

[Randy Kennison]

Excuse teh terrible syntax of the below, the default size of the Message input is about 20 characters and 3 lines on this PC for some unknown reason. Makes it very very difficult to type anything at all.
>Using the grouping grid and CollectionBase datasources, is it possible to display a parent child type relationship as it is with DataSets? I''d be using a DataSet, except the performance is terrible at best. In any event, Class A has say 2 Col''s, A and B. Col B has 2 col''s, A and C. ( The A''s from each being the same data, Class A will hold a single record for each A, while class B will hold multiple records for each A value.

[Administrator]

Yes, you can define relations between primary and foreign key columns with any IList derived classes. They don''t need to be datasets.

To do that, you have to manually add a GridRelationDescriptor to the groupingGrid.TableDescriptor.Relations collection.

Stefan

[Administrator]

I forgot: You need to register the different lists with Engine.SourceListSet.

Let me know if you need more help.

Thanks,
Stefan

[RKennison]

Actually yes.I''m having a hell of a time finding doc''s on this or samples.

Basicly i have 2 classes. A , B let''s say each have members a and b. Both classes are derived from collection base.

I am trying to set it so that class B''s data shows as a "sub" grid to the rows from class A.

Been looking at GridRelationDescriptor. But i fail to see how to set the datasource for the secondary. I did add both with the set function already though.

>I forgot: You need to register the different lists with Engine.SourceListSet.
>
>Let me know if you need more help.
>
>Thanks,
>Stefan
>

[Administrator]

Attached find a sample project that demonstrates how to manually specify master-details relations between three separate tables that primary keys and foreign key columns in common. ManualRelation_9189.zip Stefan

[RKennison]

You would think with an example.....

I have the following in my code now after looking though your example. Thank you very much. But I still can''t get it to work, as a matter of fact, my root level data doesn''t show but one record when in this condition. Here is what i have before i

[RKennison]

( limited msg length? )

GridRelationDescriptor parentToChildRelationDescriptor = new GridRelationDescriptor();
parentToChildRelationDescriptor.ChildTableName = "EQSE_Atkrs"; // same as SourceListSetEntry.Name for childTable (see below)
parentToChildRelationDescriptor.RelationKind = RelationKind.RelatedMasterDetails;
parentToChildRelationDescriptor.RelationKeys.Add("ID", "FightID");

this.eGrid.TableDescriptor.Relations.Add(parentToChildRelationDescriptor);

this.eGrid.Engine.SourceListSet.Add( "EQSE_Fights" , e.eData.eFights );
this.eGrid.Engine.SourceListSet.Add( "EQSE_Atkrs" , e.eData.eAtkrs );

this.eGrid.DataSource = e.eData.eFights;

[RKennison]

Class fights is of collectionbase, as is atkrs. Is there something i have to do inside the fight/atkr classes to make this work? As it is, I bomb out somwhere inside of is_expanded function ( stack trace ).

[RKennison]

This has to be something I''m missing in the "key" part. If i Comment out the 2 lines .. RelationKey.. and the next where it "adds" the key, it works until I click on the + button to expand. I crash there. So I''m assuming there is something in my collectionbase class . that i''m missing.

When the grouping engine is looking for data in the child / parent class based on the "key" fields specified.. how does it do this?
I have a feeling it''s looking for something my classes
that do not exist.

[Administrator]

Could it be you just have to switch the two?

parentToChildRelationDescriptor.RelationKeys.Add("ID", "FightID");

to

parentToChildRelationDescriptor.RelationKeys.Add("FightID", "ID");

The first parameter needs to be a valid field/column in the parent collection. The second paramter must be from the child table.

Stefan

[RKennison]

Wow.... ID is in the parent table, fights. FightID is in the atkr table. Add''s doc''s show parent , child order.

I switched them, and it no longer crashes, and actually opens a header line, no data is showing up though. I have manually verified it exists.. have to figure that one out. Is there anything special in my CollectionBase derived class that must be overridden to define a column?

public long ID
{
get{ return lFightID; }
set{ lFightID = value;}
}

[RKennison]

Darn.. Actually , it works now, but I have to comment out the relationkind setting, and my "sub" grid, shows every record. I tried the other Kind values, none worked. But not specifiying one at least no longer blows up ;)

[RKennison]

I will pull my hair out.... it only doesn''t crash if that view is active when it''s drawn. if it''s drawn in the background it still fries...

[RKennison]

Here is one for the books....

DevPartner Studio. This was the problem. I compleltly removed it, and all is well now. Go Figure. Anyway thanks for the help. Your sample still showed me many a few things I was missing. If only DataSet''s had some speed to them....