How does OpenLayers GetFeature filter strategy work?

Question

I want to select on map that "res_id = 182" but that is selecting all objects on the map.

var filter = new OpenLayers.Filter.Comparison({
    type: OpenLayers.Filter.Comparison.EQUAL_TO,
    property: "res_id",
    value: "182"
});

var  filterStrategy = new OpenLayers.Strategy.Filter({filter: filter});

var control = new OpenLayers.Control.GetFeature({
    protocol: OpenLayers.Protocol.WFS.fromWMSLayer(mylayer),
    strategies: [new OpenLayers.Strategy.Fixed(),filterStrategy],
    box: true,
    multipleKey: "shiftKey",
    toggleKey: "ctrlKey"
});

I actually want to select an area on map and filter selected items by attribute from combobox.

Answer 1

Well, you can try CQL-filters for attribute-based queries on WMS. Look this thread for how to filter features of a wms. Afterwards you may select features from your WFS obtained from this WMS. BTW.: the GetFeature-control is designed for selecting features by mouse rather then by any query. To select a feature you may use the SelectFeature-control. Loop the features within your map and activate the control for the desired one as suggested in this thrad. You may also have a look at this thread if you are to use the WFS-built-in filter abbilities.