Assuming you only need keys, use the property Keys:
foreach (string key in dict.Keys)
{
...
}
If you want to simply get all the keys in a readable form in the immediate window, you can use:
string.Join(";", dict.Keys)
pre -.NET 4:
string.Join(";", dict.Keys.ToArray())
... .NET 2, - :
string.Join(";", new List<string>(dict.Keys).ToArray())
, KeyValuePair .
EDIT: , Visual Studio , . , , VS2008:

... VS2010 . " " " "? , .