String.Compare or String.ToLower

// Bad!
Example: (ToLower() creates a temp string)
int id = -1;
string name = "lance hunt";
for(int i=0; i < customerList.Count; i++)
{
  if(customerList[i].Name.ToLower() == name)
  {
    id = customerList[i].ID;
  }
}

// Good! (but not for all cultures)
int id = -1;
string name = "lance hunt";
for(int i=0; i < customerList.Count; i++)
{
  // The “ignoreCase = true” argument performs a
  // case-insensitive compare without new allocation.
  if(String.Compare(customerList[i].Name, name, true)== 0)
  {
    id = customerList[i].ID;
  }
}

// Good! (now also for all cultures)
int id = -1;
string name = "lance hunt";
for (int i = 0; i < customerList.Count; i++)
{
  // The StringComparison.OrdinalIgnoreCase argument performs a
  // case-insensitive compare without new allocation and for several cultures. 
  if (String.Compare(customerList[i].Name, name, StringComparison.OrdinalIgnoreCase) == 0)
  {
    id = customerList[i].ID;
  }
}

Een leuke referentie is de zogenaamde Turkey Test.