Preventing databind in PageLoad

[improwise]

How do we prevent data binding form occuring in PageLoad and, here's the catch, still get the RadGrid to display including the filters, which we use as a search form? Something like:

        if (e.RebindReason != GridRebindReason.InitialLoad)
            ((RadGrid)sender).DataSource = new object[] { };

Will prevent the data binding, but it will also prevent the user from ever doing a real search :)

[improwise]

Can answer my own question, to help others who may face the same problem. Basically, what we did was to create an empty "resultset" from the Business Layer, and bound to that:

if (e.RebindReason == GridRebindReason.InitialLoad)
    ((RadGrid)sender).DataSource = new List<BookTransaction>[] { };
else
{
    ((RadGrid)sender).DataSource = eodsObjectDataSourceBookTransaction;

}

(Please note that we are using Entity Framework thus working with real objects, BookTransaction is an entity).

[improwise]

Turns out this affected updates/inserts also (for obvious reasons). Is there a way to prevent databind at PageLoad(), but still be able to use automatic dataoperations etc as you would normally do? The only thing we want to do is to prevent the RadGrid from binding at PageLoad(), but still be displayed as the searchform is implemented as filters in the grid, but the rest should be the same.

I know you can use the RadGrid1_UpdateCommand but that solution I feel is a bit to complicated and hard to maintain, and it doesn't work to well using Entity Framework (where objects are used). I guess you would be forced to use statements like

MyObject.MyProperty = updatedValues.myNewValue

which is hard to maintain over time.

[Nikolay Rusev]

Hello Patrik,

Yes, the approach from your last post should do the trick for you.

Best wishes,
Nikolay
the Telerik team

[improwise]

Yes, it will, but when wokring with objects, it will force you to use reflection to be able to fill the object properties with the values from the EditForm, which is a bit complex.

An alternative solution, which perhaps isn't the prettiest, but should be easier to maintain, would be to have a filterExpression that would make sure you got no hits, which would result in an empty RadGrid (even though it would do a roundtrip to the database). In our case, we actually export the filterExpression in LINQ to the Business Layer, so this roundtrip wouldn't be to coslty (no rows would be sent from the database). Telerik, what would be the best method of implementing such a solution? I guess what we are talking about would be some kind of default filterExpression which would only last the first databind (PageLoad), which is then replaced with "real" filterExpressions as the search form/filter form is used (which should be handled by itself, stanard procedure).

[improwise]

We experimented a bit with filterExpressions by simply setting it to "false" by default:

FilterExpression="false"

and this seem to work quite well, and is a solution much easier to maintain we think. In our case, we export the LINQ filterExpression to our BusinessLayer and DataLayer, so we won't actually fetch any unnecessary data, but I guess it could be used by anyone wanting to have an empty grid on pageload no matter what, if you are prepared to do the databind and load data, even though it wont be displayed by the RadGrid.

[Nikolay Rusev]

Hello Patrik,

You will need at least binding to empty collection in order RadGrid to render it's structure.

Best wishes,
Nikolay
the Telerik team

[improwise]

Nikolay, what is this latest replyan answer to? I mean, isn't it a repeate of what was written in the second reply above? :)

[Nikolay Rusev]

Hello Patrik,

Yes it is repeated with the statement in the second reply.

Nikolay
the Telerik team

[Suresh]

Hello All and Telerik Admin,

I have tried one trick that is... I added an "if condition" of Page.IsPostback

If page is postback, I let the "OnNeedDataSource" code run else nothing.. And it seems working...

 

Could you please confirm if this approach is good to go with?