RadFilter: adding a filter with a value in the code

Here's the code where I add the filter:

RadFilterEqualToFilterExpression<Boolean> estVersionAnterieureEqualToFilterExpression = new RadFilterEqualToFilterExpression<Boolean>("EstVersionAnterieure");
estVersionAnterieureEqualToFilterExpression.Value = true;
this.RadFilter1.RootGroup.AddExpression(estVersionAnterieureEqualToFilterExpression);
RadFilter1.FireApplyCommand();