IDictionary[] and Hashtable results cast
22 March 2010
The following code will not build:
string hold_value;
Hashtable openWith = new Hashtable();
openWith.Add("txt", "notepad.exe");
openWith.Add("bmp", "paint.exe");
openWith.Add("dib", "paint.exe");
openWith.Add("rtf", "wordpad.exe");
foreach (DictionaryEntry de in openWith)
{
hold_value = openWith[de.Key];
Console.WriteLine("Key = {0}, Value = {1}", de.Key, hold_value);
};
it returns the following error:
Cannot implicitly convert type 'object' to 'string'. An explicit conversion exists (are you missing a cast?) C:\Users\[Path]\Program.cs
when returning a valuable from IDictionary (e.g. when using a Hashtable) you need to use a cast operation:
hold_value = (string)openWith[de.Key];
This is probably less obvious when using a bespoke dictionary only holding values of a custom type ("Vehicle" for example) than with the more generic Hashtable data collection.
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