Many-to-Many DATARELATION :Couldnt' figure it at all
hi,,
I have 4 tables. t1, t2, t3, t4.
t2 and t4 are many to many.
DATAGRID 1:
t1 - parent table - Primarykey (t1-ID)
- t2 child table -Primary key (t2-id), Foreign Key (t1-ID), column (t3-ID)not unique, and more columns
DATAGRID 2:
t3 - parent table - Primarykey (t3-ID)
- t4 child table -Primary key (t4-id), Foreign Key (t3-ID) not unique, and more columns
DATAGRID 3 :
I need to display the corresponding records in t4 for selection of 't2' in datagrid 1..
As u can see the link for the two tables 't2' and 't4' is "t3-ID"...
How to do this?
I have 4 tables. t1, t2, t3, t4.
t2 and t4 are many to many.
DATAGRID 1:
t1 - parent table - Primarykey (t1-ID)
- t2 child table -Primary key (t2-id), Foreign Key (t1-ID), column (t3-ID)not unique, and more columns
DATAGRID 2:
t3 - parent table - Primarykey (t3-ID)
- t4 child table -Primary key (t4-id), Foreign Key (t3-ID) not unique, and more columns
DATAGRID 3 :
I need to display the corresponding records in t4 for selection of 't2' in datagrid 1..
As u can see the link for the two tables 't2' and 't4' is "t3-ID"...
How to do this?
One way to do this is to capture the CurrentCellChanged event on DataGrid1 if the CurrentRow is different then previously, then get the t3-id and loop through table 4 getting all records that have a mathcing t3-id and add those records to DataGrid3...
ASKER
pls can u show me in code...what will happen in
mydatagrid_currentcellchan
{
// ? mydatagrid.currenrowIndex ?
//how to check if current row is different
// how to get the column field i.e t3-ID
// how to loop through the table4
// mydatagrid3.bind();
}
mydatagrid_currentcellchan
{
// ? mydatagrid.currenrowIndex ?
//how to check if current row is different
// how to get the column field i.e t3-ID
// how to loop through the table4
// mydatagrid3.bind();
}
ASKER CERTIFIED SOLUTION
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ASKER
before the 'foreach' statement
i did this
DataTable dt_new = new DataTable();
dt_new = mydataSet1.t4 ;
and then used that in the 'foreach'
----- foreach ( DataRow dr in dt_new ) { createrows and bindgrid} ------
but its giving me this error
--------------------------
"foreach statement cannot operate on variables of type 'System.Data.DataTable' because 'System.Data.DataTable' does not contain a definition for 'GetEnumerator', or it is inaccessible"
--------------------------
and Should this "private int lastRowIndex = 0;"
be "static int lastRowIndex;"
ASKER
oh..
it has to be
foreach ( DataRow dr in dt_new.Rows)..
---> dt_new.Rows
And when i run the program
it gives an exception : System.Argument exception at the "foreach( DataRow dr in dt_new.Rows).."
additional information : "this row is already in another table"
Question : WE are trying to get the rows from a different table in the dataset using the DataRow object., when the currentcellchanged event is fired. is that possible?
it has to be
foreach ( DataRow dr in dt_new.Rows)..
---> dt_new.Rows
And when i run the program
it gives an exception : System.Argument exception at the "foreach( DataRow dr in dt_new.Rows).."
additional information : "this row is already in another table"
Question : WE are trying to get the rows from a different table in the dataset using the DataRow object., when the currentcellchanged event is fired. is that possible?