If you are using .net 3.5/4.0 version of RadGrid filter expressions are in different format. RadGrid internally use Dynamic LINQ
in order to perform filtering. The format of the expression depends on what is the source that will be filtered.
In case of SqlDataSource format is as follow: it["FieldName"] = "Value". Thus the expressions like: Login_Name='Patrik' should look as follow: it["Login_Name"] = "Patrik".
Of course you can set EnableLinqExpressions to false of RadGrid and then use sql like expressions - same as for SqlDataSource.
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