Top Tip : how to use LoadSettings() with an OpenAccessLinqDataSource

[Eric Mooiweer]

When using LoadSettings() with an OpenAccessLinqDataSource be careful to specify DataSourceControlID="MyOpenAccessLinqDataSource" and not FilterContainerID="MyRadGrid".

If you're not using LoadSettings(), the RadFilter works OK with both strategies but if you're using a OpenAccessLinqDataSource and doing LoadSettings() then you must make the RadFilter element's DataSourceControlID attribute to refer to your datasource.

The demo for the Loading and saving of filter expressions uses a SQL data source and makes the filter point to the grid:

<telerik:RadFilter runat="server" ID="RadFilter1" FilterContainerID="RadGrid1"></telerik:RadFilter>

If instead of a SQL data source, you use a OpenAccessLinqDataSource, strange things will happen to the queries. For some reason, the query will be run a first time and then a second time but with the filter appearing *double* (where mycolumn = 1 and mycolumn = 1).

It won't fail but naturally, you don't want to execute your queries twice.

Also, visible during debug:
- in the output, a SqlSyntaxError error is thrown
- the _Selecting() event handler of the data source is called twice; the first time the data source's where property shows the correct where clause (as defined by the RadFilter that was set using LoadSettings() ); the second time with the radfilter's conditions repeated.

I found that declaring RadFilter as seen in the demo for integration with the data source works :

<telerik:RadFilter runat="server" ID="RadFilter1"
  DataSourceControlID="EntityDataSourceCustomers"
 OnApplyExpressions="RadFilter1_ApplyExpressions">
</telerik:RadFilter>

NOTE: I am not sure if this behaviour is specific to OpenAccessLinqDataSource or if it also happens with the SQL source. I didn't check.

[Vasil]

Hi Eric,

Thank you for sharing your findings.
It is strange that the condition is repeated. I will check it and if it is a bug we will try to fix this.

Regards,
Vasil
Telerik