Uppercase and Lowercase
The ToUpper and ToLower methods
convert a string in uppercase and lowercase respectively. These methods
are easy to use. The following code shows how to use ToUppler and
ToLower methods.
string aStr = "adgas";
string bStr = "ABNMDWER";
string strRes = aStr.ToUpper();
Console.WriteLine("Uppercase:"+ strRes.ToString());
strRes = bStr.ToLower();
Console.WriteLine("Lowercase:"+ strRes.ToString());
Read C# Strings
to learn more about strings in C#.