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copied!<p>Surely you simply need to repopulate the second combo box's items when the user makes a selection in the first?</p> <p>You likely don't want to requery the database each time the user makes a selection and so instead will want to hold a structure in memory of all valid facets keyed on toolid.</p> <p><strong>EDIT</strong> some further detail based on Dave's comment:</p> <p>Assuming that you already have some code setup to query the database, you want to execute a query (or queries) that give you back the relevant data to hold in a cache and do this as part of your app's initialisation after connecting to the database. You could create two dictionaries to hold the tool and facet data. For example:</p> <pre><code>Dictionary<int, string> _tools = new Dictionary<int, string>(); Dictionary<int, string> _facets = new Dictionary<int, string>(); </code></pre> <p>and then a third structure that basically holds the data in tool_facet:</p> <pre><code>Dictionary<int, List<int>> _tool_facets = new Dictionary<int, List<int>>(); </code></pre> <p>these basically give you an in-memory copy of the tables that you can very quickly enumerate to populate combo boxes. You'll want to populate the combo boxes with something that holds the ID and a description, something like this will do:</p> <pre><code>class ComboBoxIntItem { private readonly int _id; private readonly string _name; public ComboBoxIntItem(int id, string name) { _id = id; _name = name; } public override string ToString() { return _name; } public int GetId() { return _id; } } </code></pre> <p>I'm assuming here that you need to know the tool and facet IDs that the user has selected. If you only care about the names then you could just use a single structure like this:</p> <pre><code>Dictionary<string, List<string>> _tool_facets = new Dictionary<string, List<string>>(); </code></pre>

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