I have a report that's being populated from an ObjectDataSource. The report includes expandable/collapsible nodes per user.
I'm allowing the viewer to filter the report by setting the FilterExpression on the datasource, then calling ReportViewer1.LocalReport.Refresh(). This is done during PostBack.
This filters the results, but the state of the expanded/collapsed nodes is lost. Is there some way to store the expanded/collapsed nodes in the ViewState? Or is there a better way to accomplish this altogether?
I know its been a while since this question was asked, but since i had to go through this recently i want to share my experience with somebody who might be dealing with this.
It's tricky but if you add a multivalued parameter to your report and the values match the values in the toggable fields, then you can write a group expression in the grid (And in the labels so those go away too). Once that is done, you just have to keep track of what is toggled (this is hard, but is possible with javascript).
Basically, there are two of the hidden child controls in the reportviewer control (indexes 4 & 5 in vs2008) that have the name of the event and the id of the table cell clicked, with this you cand build an array in javascript and keep track of the status of all toggable fields.
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I have an app page that shows information from the same table in 2 places on a page.
In the place A, I want an editable field that is owned by the current user.
In the place B, I want to see the list of entries for all users.
I thought I could somehow have two pointers into the same table by configuring more than one datasource for the table, and bind placeA/B widgets to the two separate datasource.
However, I could not find out how I can bind a panel or widget to a specific datasource within a table.
What bugs me is that clearly the UI allows me to add multiple datasources for a table, so I probably misunderstand what the usercase for multiple datasources are.
My current plan is to ivestigate whether I can create a computed datasource that limits results to just the current user, but I don't understand how I could updated a computed datasource (which is something I want to do).
This is probably less than clear, happy to add clarifying information.
Many thanks in advance for any help
Never mind. App maker behaves as I thought it should be. The two datasources are behaving as two cursors into the same table. For some reason, I could not seem to find the 2nd datasource in the widget dropdown for datasource, but I could find it by selecting "Advanced" and then finding datasource starting from "datasources" instead of "widget.datasource".
Nothing to see here, move along now ;)
I'm working on a project in ASP.Net that uses the UpdatePanel to handle all AJAX requests. I'm much more familiar with using jQuery AJAX methods (and strategies) so I'm kind of stumped on finding a clean solution for the functionality I need.
Basically I need a table that allows me to dynamically add as many rows as I want using AJAX. These rows will contain text boxes whose values must be preserved by ASP.Net until I'm ready to submit the form. To further complicate matters there may already be records that exist in the database that should display as well with the values pre-populated and any changes to these fields must also be preserved.
I had started out by using a GridView and setting it's datasource to a list of the database records but unfortunately I believe this means I can't add new rows to the GridView.
Any assistance would be much appreciated. Keep in mind the solution must use ASP.Net controls.
I believe I figured out a solution that seems pretty straightforward.
When the page loads I gather any relevant records from the database and perform a query expression combined with a projection select to create an anonymous type array. When the add new row button is clicked instead of trying to add the row directly or retrieve potentially old data from the database I perform a query expression on the datagrid items themselves and union a new blank item. From there it's just a simple matter of setting the datagrid data source, triggering a databind and updating the update panel.
The only question now is how to identify the rows, particularly new rows that have no database keys yet. I could devise some clever method for generating row ids but I have a feeling that ASP.Net already does this and all I need to do is associate these ids with the anonymous types.
I would like to fetch a number of records from a database to fill a DropDownList that is filled in a OnItemDataBound of a DataList.
I think it might be a bit much to fetch all the records every time a DropDownList is bound since they are the same.
How can this be done?
If I understand your question correctly, you could put your drop down list into a user control, and then output cache it, which would mean the resulting drop down list would not keep making new requests to the database each time it is loaded.
MSDN has quite a good article on output caching:
http://msdn.microsoft.com/en-us/library/hdxfb6cy.aspx
Say I have 2 tables in a database, each with 100,000's of rows in detail and 10,000's of rows in the master 5 columns each, properly indexed and related. I want to have master/detail nested gridviews. What's the fastest architecture I could design in .net to do this? The largest result set on the master could be in the thousands (usually in the tens though) and the detail per records could be in the hundreds (usually in the single digits though). I'd like to be able to do a display all masters if possible.
The bottom line: bind to DataReaders, use Repeaters instead of GridViews, and turn off ViewState.
The design you're proposing is going to be pretty hard on your users (thousands of records, yikes), but you probably already know that.
If this is just for display and you want the absolute fastest architecture for Asp.Net, you should obtain an IDataReader for each data segment (master and child), sorted such that you can manually match child records while reading both resultsets in a forward-only fashion. (See Scott Mitchell's Why I don't Use DataSets in my ASP.NET Applications for some details about DataReader performance - as long as you aren't optimizing prematurely, it's quite good advice.)
Instead of using a GridView, I'd use a Repeater which has less overhead and lets you write more compact HTML (for a smaller payload to the client): bind the master IDataReader to that repeater. (I'm not sure whether you meant the GridView control, or just a conceptual grid - the basic architecture would be the same for a GridView)
Then add a handler to the Repeater.ItemDataBound that checks if the child data reader's current record matches. If it does, manually render your detail data for that master record.
Finally, you should also turn ViewState off, at least for the Repeater (preferably for as much of the page as possible), again so that the HTML payload is smaller.
If you're totally committed to nested GridViews, particularly to using a GridView to render the detail data, it's going to hurt the performance one way or another, because you'll have to either make many more database calls (to obtain discrete resultsets you can bind to) or you'll have to massage the detail data into an intermediary container.
I'm writing an internal web application that is used to look up credit checks. I'm using ASP.NET for this website.
I have a SQL Query that I have to query the credit check database and it returns a datatable of results. After the person clicks search, I run the query and bind the returned datatable to the Gridview every time the user clicks the search button.
This works fine, and it populates my gridview like it should.
How do I maintain the data that is bound to my gridview beyond postback? For example, lets say a person clicks Page 2 of the paginated gridview... how do I keep from losing the data of the gridview during that postback?
Currently I am storing the datatable in session[] but I don't think I should be doing this, because the size of this table is very large (sometimes hundreds of thousands of results!)
Do I need to re-query the database for each postback? The query takes a decent bit and I'd rather not if I could help it.
What is the common solution here?
If you are storing the data in the session I would make sure viewstate is turned off and you are rebinding it on each postback so at least your not storing all that data in 2 places.
You could also considered leaving the viewstate on and changing logic that grabs the session data to bring back one page of data at a time? You would take in the current page and JUST return that page's data so that you could get all the data at first and store it in the session. Then if any other postback actions occurred during that page view where nothing was really going on with the grid you wouldn't have to rebind each time.
I have found that most of the issues I have run across in the past due to too much data being displayed in a grid were more design issues and I would step back and look at the overall problem that was trying to be solved and implement another solution to not have to display so much data. Usually a customer/user asks for everything because they don't consider any alternatives or the impact of their request.
Several things:
Clicking on "Page 2" should not result in a postback - it should be a simple GET request.
Do not allow GridView to store its data in the ViewState: cache data manually and "rebind" datasource on each request
Use ASP.NET MVC