How to write quality code? Tip1, StringOperations

1. Use StringBuilder instead of string variable in case of concatenations.

C# Code (Wrong)	C# Code (Correct)
String xXml = “”; for(Int32 nRep = 1; nRep<=Reps; nRep++ ) { sXml += "<Order orderId="" + nRep + "" orderDate="" + DateTime.Now.ToString() + "" customerId="" + nRep }	// make sure that the StringBuilder capacity is large enough for the resulting text StringBuilder oSB = new StringBuilder(165); for (Int32 nRep = 1; nRep <= Reps; nRep++) { oSB.Append("<Order orderId=""); oSB.Append(nRep); oSB.Append("" orderDate=""); oSB.Append(DateTime.Now.ToString()); oSB.Append("" customerId=""); oSB.Append(nRep); }

Note:

• Use + When the Number of Appends Is Known or Fixed (String str = str1+str2+str3)
• The StringBuilder class starts with a default initial capacity of 16. Strings less than the initial capacity are stored in the StringBuilder object.

2. Use the Overloaded Compare Method for Case-Insensitive String Comparisons as shown below.

C# Code (Wrong)	C# Code (Correct)
// Bad way for insensitive operations because ToLower creates temporary strings String str="New York"; String str2 = "New york"; if (str.ToLower()==str2.ToLower()) // do something	str.Compare(str, str2, false);

Useful links on string:-

• “Improving String Handling Performance in .NET Framework Applications” http://msdn2.microsoft.com/en-us/library/aa302329.aspx
• “Chapter 5: Improving Managed Code Performance” http://msdn2.microsoft.com/en-us/library/ms998547.aspx#scalenetchapt05_topic26
• "Concatenating Strings Efficiently", http://www.yoda.arachsys.com/csharp/stringbuilder.html