Buscando numero de veces que aparece un caracter en string

[Peterpay]

Pues es simple de implementar

public int TimesContained(string value,char lookingfor)
{
Dictionary<char,int> exists=new Dictionary<char,int>();
exists.Add(lookingfor,0);
foreach(char currentChar in value)
{
if( currentChar==lookingfor)
{
exists[lookingfor]++;
}
}
return exists[lookingfor];
}