I have an object of the type IEnumerable
, I am using
var getResult= keyValueList.SingleOrDefault()
I recommend more understanding way using extension method:
public static class KeyValuePairExtensions
{
public static bool IsNull<T, TU>(this KeyValuePair<T, TU> pair)
{
return pair.Equals(new KeyValuePair<T, TU>());
}
}
And then just use:
var countries = new Dictionary<string, string>
{
{"cz", "prague"},
{"de", "berlin"}
};
var country = countries.FirstOrDefault(x => x.Key == "en");
if(country.IsNull()){
}
Try this:
KeyValuePair<string,int> current = this.recent.SingleOrDefault(r => r.Key.Equals(dialog.FileName) == true);
if (current.Key == null)
this.recent.Add(new KeyValuePair<string,int>(dialog.FileName,0));
Try this:
if (getResult.Equals(new KeyValuePair<T,U>()))
or this:
if (getResult.Equals(default(KeyValuePair<T,U>)))
From your original code it looks like what you want is to check if the list was empty:
var getResult= keyValueList.SingleOrDefault();
if (keyValueList.Count == 0)
{
/* default */
}
else
{
}
You can create a general (and generic) extension method, like this one:
public static class Extensions
{
public static bool IsDefault<T>(this T value) where T : struct
{
bool isDefault = value.Equals(default(T));
return isDefault;
}
}
Usage:
// We have to set explicit default value '0' to avoid build error:
// Use of unassigned local variable 'intValue'
int intValue = 0;
long longValue = 12;
KeyValuePair<String, int> kvp1 = new KeyValuePair<String, int>("string", 11);
KeyValuePair<String, int> kvp2 = new KeyValuePair<String, int>();
List<KeyValuePair<String, int>> kvps = new List<KeyValuePair<String, int>> { kvp1, kvp2 };
KeyValuePair<String, int> kvp3 = kvps.FirstOrDefault(kvp => kvp.Value == 11);
KeyValuePair<String, int> kvp4 = kvps.FirstOrDefault(kvp => kvp.Value == 15);
Console.WriteLine(intValue.IsDefault()); // results 'True'
Console.WriteLine(longValue.IsDefault()); // results 'False'
Console.WriteLine(kvp1.IsDefault()); // results 'False'
Console.WriteLine(kvp2.IsDefault()); // results 'True'
Console.WriteLine(kvp3.IsDefault()); // results 'False'
Console.WriteLine(kvp4.IsDefault()); // results 'True'
if(getResult.Key.Equals(default(T)) && getResult.Value.Equals(default(U)))