Question

I want to allow the user, when searching for a Platypus, to enter either the Platypus’ ID or Name (or portion of a name).

The database is down right now, so I can’t test this code, but the fact that I’m assigning to kvp twice doesn’t seem right. Anyway, first my code:

String SearchVal = textBoxPlatypusNumOrPartialName.Text.Trim();
int PlatypusID;
int.TryParse(SearchVal, out PlatypusID);

Dictionary<int, string> CandidatePlatypusDict = PlatypusID > 0 ? PlatypusSetupData.GetPlatypusById(PlatypusID) :        PlatypusSetupData.GetCandidatePlatypusFromName(SearchVal);

KeyValuePair<int, String> kvp = new KeyValuePair<int, string>();
using (var getPlatypusIDAndNameDlg = new GetPlatypusForm(CandidatePlatypusDict)) {
    DialogResult dr = getPlatypusIDAndNameDlg.ShowDialog();
    if (dr == DialogResult.OK) {
        kvp = getPlatypusIDAndNameDlg.PlatypusKVP; 
    }
}

…Now, if I try this instead:

KeyValuePair<int, String> kvp; // = new KeyValuePair<int, string>();

I get: “Use of unassigned local variable ‘kvp'”

And I can’t assign null as KeyValuePair, as it is a non-nullable type.

Is this instantiation of kvp followed by assignment to it okay, and if not, how can I work around it?

Answer 1

Is this instantiation of kvp followed by assignment to it okay, and if not, how can I work around it?

Well it’s okay – but you might instead want:

KeyValuePair<int, String> kvp;
using (...) {
   kvp = dr == DialogResult.OK ? getPlatypusIDAndNameDlg.PlatypusKVP 
                               : /* some other value here */;
}

That way it’s clearly only assigned once, but is always assigned. Next you need to work out what value you want it to have in the situation where dr isn’t DialogResult.OK.