How can I detect if this dictionary key exists in C#?

Question

I am working with the Exchange Web Services Managed API, with contact data. I have the following code, which is functional, but not ideal:

foreach (Contact c in contactList) {     string openItemUrl = "https://" + service.Url.Host + "/owa/" + c.WebClientReadFormQueryString;      row = table.NewRow();     row["FileAs"] = c.FileAs;     row["GivenName"] = c.GivenName;     row["Surname"] = c.Surname;     row["CompanyName"] = c.CompanyName;     row["Link"] = openItemUrl;      //home address     try { row["HomeStreet"] = c.PhysicalAddresses[PhysicalAddressKey.Home].Street.ToString(); }     catch (Exception e) { }     try { row["HomeCity"] = c.PhysicalAddresses[PhysicalAddressKey.Home].City.ToString(); }     catch (Exception e) { }     try { row["HomeState"] = c.PhysicalAddresses[PhysicalAddressKey.Home].State.ToString(); }     catch (Exception e) { }     try { row["HomeZip"] = c.PhysicalAddresses[PhysicalAddressKey.Home].PostalCode.ToString(); }     catch (Exception e) { }     try { row["HomeCountry"] = c.PhysicalAddresses[PhysicalAddressKey.Home].CountryOrRegion.ToString(); }     catch (Exception e) { }      //and so on for all kinds of other contact-related fields... } 

As I said, this code works. Now I want to make it suck a little less, if possible.

I can't find any methods that allow me to check for the existence of the key in the dictionary before attempting to access it, and if I try to read it (with .ToString()) and it doesn't exist then an exception is thrown:

500
The given key was not present in the dictionary.

How can I refactor this code to suck less (while still being functional)?

Answer 1

You can use ContainsKey:

if (dict.ContainsKey(key)) { ... } 

or TryGetValue:

dict.TryGetValue(key, out value); 

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Update: according to a comment the actual class here is not an IDictionary but a PhysicalAddressDictionary, so the methods are Contains and TryGetValue but they work in the same way.

Example usage:

PhysicalAddressEntry entry; PhysicalAddressKey key = c.PhysicalAddresses[PhysicalAddressKey.Home].Street; if (c.PhysicalAddresses.TryGetValue(key, out entry)) {     row["HomeStreet"] = entry; } 

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Update 2: here is the working code (compiled by question asker)

PhysicalAddressEntry entry; PhysicalAddressKey key = PhysicalAddressKey.Home; if (c.PhysicalAddresses.TryGetValue(key, out entry)) {     if (entry.Street != null)     {         row["HomeStreet"] = entry.Street.ToString();     } } 

...with the inner conditional repeated as necessary for each key required. The TryGetValue is only done once per PhysicalAddressKey (Home, Work, etc).