I have a list of values in a SQL Table which are used to popluate a DropDownList, having a unique Integer as the value of each item and a String as the visible text (via SqlDataSource). There is also a third field in the database which is a flag to indicate whether the list item is active or not (inactive items are not shown in the DropDownList)
Selections made in the dropdown are stored in the database as their integer value (as part of a dataset making up the overall record), not the text value.
Over time, the items in the DropDownList may be removed by marking the items as inactive. However, there is still a need to open old records which may have had a now-inactive item as part of it's data...
My question is, what's the best way to ensure that the missing value included in the dropdown for the old record?
The two methods that spring to mind are to either:
Populate DropDownList with only the currently active items and, when loading a record, catch when the app tries to select a value that doesn't exist, go back to the db to see what it should be (the text value) and manually add it into the dropdown.
or...
Populate DropDownList with all list items (both active and inactive), load the record and then programatically remove all the inactive items (execpt for any that are now selected).
Neither of these seem particularly efficient, so I was wondering whether there is a best practice for this kind of thing?
there are so many optimum ways to do that sort of things, i am defining here a couple of them, use any of following if your Drop down list items count is less than 200 , lets say drop down list is of Products
1)
i) Load all Products records in drop down list and hide the inactive ones by setting visible=false
i) When you load a user record than look for its drop down list value if its visible than select it and enjoy, if its not visible than make it visible by setting its property visible=true and select it and also set its index or id in a flag to change its visibility(visible=false) again after your/users required operation performed.
2)
i) load only active Product records in drop down list ii) while loading a user record also load its product details(name, id, inactive_status) using Joins in sql.
iii) check in that user record if item is inactive then add its record in drop down list as you have all its details now with user details record else just select it.
IMPORTANT NOTE: if you drop down list has items in millions than use ADVANCE SEARCH techniques
The first thing I would do is question your business logic - should you be able to make an item inactive if it is being used as a foreign key in an active row elsewhere? If you make it inactive should it not remove all foreign keys as well?
To answer your question though I would go with a variation on the second idea but filtering in the page like that is probably slower than doing directly with SQL so I guess you have something like this at the moment to populate the dropdown
SELECT * FROM Table WHERE Active = 1
You should already have your record and the foreign key value so I would change it to this
SELECT * FROM Table WHERE Active = 1 OR PrimaryKey = [YourForeignKey]
Then you will always have the selected item but should also be fairly efficient.
Related
Currently my dropdownlist returns a value that I use in a SQL WHERE clause to return a result set. I would like to be able to just move to the selected record as oppose to filtering the whole set. When I filter I am no longer able to page through the records (I can only choose another search selection from the dropdownlist because there are no other records to page through - I would like to use both). What is the best way to achieve this?
I have a form that submits parameters to a query, then opens the resulting record in another form. The problem is, whenever there is more than one record it automatically puts the first one into the from without any kind of option to choose the record I want. I have a macro set up on the search button on the first form that submits the parameters to the query and then displays it in the second form, I've tried to set up another macro in between the two, but I don't know if it's possible to set up the expression creator to check the number of rows resulting from a query. Is it possible to modify the query to create a prompt to choose which record I want? Or should I change something else?
This is the query:(automatically created by access)
SELECT CHILD.CHILD_L_NAME, CHILD.CHILD_F_NAME, CHILD.DOB, CHILD.GENDER, CHILD.DAYS_IN_CARE,
CHILD.HOURS_PER_DAY, CHILD.ENROLLMENT_DATE, CHILD.CHILD_ADDRESS, CHILD.CHILD_CITY,
CHILD.CHILD_ZIP, CHILD.CHILD_STATE, CHILD.CLASSROOM, CHILD.SNACK, CHILD.LAST_UPDATED, CHILD.CIN
FROM CHILD
WHERE (((CHILD.CHILD_L_NAME)=[Forms]![Search]![L_NAME]) AND
((CHILD.CHILD_F_NAME)=[Forms]![Search]![F_NAME])) OR
(((CHILD.CHILD_L_NAME)=[Forms]![Search]![L_NAME]) AND
((CHILD.DOB)=[Forms]![Search]![DOB])) OR
(((CHILD.DOB)=[Forms]![Search]![DOB])) OR
(((CHILD.CHILD_L_NAME)=[Forms]![Search]![L_NAME]));
If I understood well your problem and you use VBA it's quite easy to do.
You can create a reduced query based on the query you're creating with the button. This new query should include all and only the fields that allows you to discriminate beetwen the records to show in the 2nd form.
For instance it could include LastName, FirstName and classroom to select between children with same full name.
You can count the number of records of this 2nd query and if greater than 1 it means that you have more than one children to show.
So you can use this 2nd query to populate a combo-box or a listbox for selecting the record you really want to show.
When number of records is 1 you can simply skip the listbox population using an if statement on recordcount.
Next step is opening the form with the selected (or unique) record.
Bye
I'm trying to implement multiple record selection feature on a grid.
It is very similar to http://www.tek-tips.com/faqs.cfm?fid=3831
It adds an extra column with check boxes. I want those check boxes!!
But it depends on a extra logical field in the underlying table. It need to create a class clscheck which inherits CHECKBOX. I'm not sure why this CLICK procedure is needed for the checkbox.
PROCEDURE CLICK
IF DODEFAULT()
KEYBOARD '{DNARROW}'
ENDIF
ENDPROC
When I removed it, row selection did not work correctly as expected. Why this?
Here is my requirement:
1) I don't want to add an extra logical field in the underlying table.
2) To work with controls in the grid, I think AllowCellSelection must be .T. I want AllowCellSelection = .F. because I don't need to work with any control in the grid except the check boxes. I need to work only with check boxes. The other columns will be read-only.
3) Can I have selected list without the logical field in the underlying table?
4) Can I remove the usage of KEYBOARD '{DNARROW}'?
In fact, I have a grid which is AllowCellSelection = .F., but it only provides single selection.
I need to enhance it with multiple selection, thus, I just want to add an extra column with check boxes so that user can know he can select multiple records.
No need Shift+Click or Ctrl+Click which is not familiar with idiot users.
I have found this - http://www.tek-tips.com/faqs.cfm?fid=433
It also depends on an extra logical field and it depends Shift+Click and Ctrl+Click.
What you are seeing is quite common for multi-select grids. I've used them SIMILAR to this in the past. However, you are afraid of the extra column in the underlying table. That may/not be true. You don't always have to update the ORIGINAL table, but a temporary CURSOR you are presenting to the user. Ex: If you want to display a list of employees in a table. No, you don't want to keep adding this column to the original employee table as then anyone else trying to do multi-select could falsely get your selection. However, if you pulled into your own local cursor and presented to the user, then no problem. Example...
Thisform.YourGrid.RecordSource = "Employees"
(bound directly to your employee table -- not necessarily the right thing)
vs
use in select( "C_MultiPickEmployees" )
select ;
.F. as IsChosen, ;
E.* ;
from ;
Employees E;
into ;
cursor C_MultiPickEmployees READWRITE
Thisform.YourGrid.RecordSource = "C_MultiPickEmployees"
NOW, you have your extra column without dealing with issues to the underlying table. If you wanted to further filter what you were showing -- such as employees for a certain division/department, then just add that to a WHERE clause, add an Order By if so needed and you are good to go.
As for the "Allow Cell Selection", I've never had to deal with that. I just add a "checkbox" to the first column and set
Thisform.YourGrid.Column[1].CurrentControl = "CheckBoxControl"
(based on the name it is added to the column).
Then, set the column 1's "ControlSource" = "C_MultiPickEmployees.IsChosen" and you should mostly be done.
As for the "CLICK" event trying to force the down arrow. This is more for automatically scrolling to the next record so you can just click, click, click for multiple entries.
Hope this helps clarify things for you.
I have a selection list that is generated dynamically, it lists a number of checkboxes that are based on an end-user editable table, as such I have no idea what data, or how much, might be contained in this table and how many checkboxes or what they might contain, other than the primary keys of the table.
The user will select the checks they wish to see, and then control is passed to another page via PostBackUrl. The second page has to figure out which records to show (build it's where clause) based on the checkboxes checked in the previous page.
So, my problem is several-fold. First, asp:CheckBoxes don't have values. This can be worked around by a number of methods. Right now, i'm using a placeholder and dynamically creating the checkboxes in the ItemDataBound event of the DataList. I set the ID to "CheckboxKey1Key2" (where Key1 and Key2 are the primary keys of the check items).
Second, I have to walk through the controls of the PreviousPage to dig out all these values. That in itself is also a pain, but doable.
Now, my thinking is to build the where clause of my Linq2Sql query based on the keys I got from decoding the checked checkbox names. This all seems like a lot of jumping through hoops for something that shouldn't be this difficult. Am I missing something? Does anyone have any better solutions?
Make a class with a structure for your values that will be useful and easy for you to use on the result page. Then when the user clicks whatever it is they click to go to the result page, loop through the DataList, create a collection from the checked items, and you will only need to grab one object instead of everything, when you need to format your query.
Then when you get to the result page, loop through the collection and build the query in the loop. Pretty easy and not much code.
I have 2 tables with unique IDs that can be mapped to each other (one table comes from a database outside of my application but has information about the same entities I'm tracking). I want to provide a UI for linking "my" records with the "other" ones, so I can store the "other" IDs in my table for the matching records. In a nutshell, the key UI element is a dropdownlist showing the available (ie, not-yet-linked) records from the "other" table.
I have a gridview for displaying "my" records in each row, plus a column showing some info from the linked record in the "other" table, if any. The data are about buildings and properties, so it might look like this:
Building1 Dallas TX Building1_Dallas_TX
Building2 Memphis TN Bldg2_Memphis_TN
Building3 Denver CO
Building4 Seattle WA
Building5 Boston MA Building5_Boston_MA
where the first 3 columns show some information from "my" table, and the last one shows the matching record from the "other" table, where the records have already been linked, else a blank where no link has been established. My actual gridview has several more columns from "my" table, but this is enough to illustrate the need.
When Edit (not shown) is clicked for a row, I want to be able to edit all 4 columns. The first 3 are textboxes; the last column should be a dropdownlist showing all of the unlinked records from the "other" table, plus an "Unassigned" option (as the first item in the list) so records can be "unlinked" or simply left unassigned, plus (for those rows that already have a link established) the linked item (it's "used" but it needs to be in there so they can continue to use it).
I can populate the dropdownlist correctly in code-behind in the gridview RowEditing event (except for the Unassigned item which I add as a ListItem in .aspx with the AppendDataBoundItems option set to true), and I can set the correct SelectedValue on the ddl's DataBound event, but on postback when I click to Update the row, the ddl has no items in it anymore (except for the Unassigned item) so the link is always cleared. If I set a link manually by directly editing my table, everything looks fine going into Edit mode -- the ddl has the correct items in it and it pre-selects the correct item, but all is lost on the Update postback. I have tried re-binding the ddl at various stages of the page cycle but clearly I don't quite understand that cycle well enough yet because I cannot figure out how to get the user-selected item to update my table.
I've also tried populating the ddl with a SqlDataSource SelectCommand, but have had no luck including the ID of currently-linked records in the other database (even though it's available in "my" table and I set it as a GridView DataKey and add it as a ControlParameter in the SelectParameters for the SqlDataSource. Without the currently-linked record in the ddl item list, I can't keep existing links.
I'll hold off sending a code sample for now -- this message is already too long! -- in hopes that the solution is obvious from what I've described... I don't think my aim is weird, but I'm open to being persuaded otherwise.
Many thanks in advance!
Chris
Ok, I'm not going into details with code because maybe you already done what I'm about to suggest.
For the last column, the drop down list, you have to execute an SQL statement to grab you the unlinked items. Use the "WHERE xx NOT IN". For the "Unassigned" option, just add an item to the list in the same code scope as above.
Next step is to handle the GridView's editing events manually. Insert, Update and Delete.
I think that way you won't have problems.