barcode printer vb.net STRINGS AND CHARACTERS in Visual C#

Creator DataMatrix in Visual C# STRINGS AND CHARACTERS

No match found --- Title --Book title: Visual C# Recipes No match found --- Title --Book title: Pro .NET Parallel Programming Title contains search term! --- Title --Book title: Pro LINQ Title contains search term! Press enter to finish

The System.String class defines a wide range of methods that can be used to work with string values. The following sections describe the most commonly used, broken down by category.

Table 16-4 describes the method available for manipulating strings. As previously mentioned, string values are read-only, and so those methods that seem to edit the value of a string are in fact creating new string values. See the Combining Strings section earlier in this chapter for a demonstration of the effect this can have. Table 16-4. Members of the System.String Class for Manipulating Strings

Concat(string, params string) Format(string, object)

Concatenates string values. Overloaded versions of this method are available to concatenate string arrays and string representations of objects. Applies formatting to a string; see the Formatting Strings section later in this chapter for details. There are several overloaded versions of this method available. Inserts the string parameter into the current string instance at the specified int index. Creates a new string by concatenating the elements of the IEnumerable<string> using the string parameter as a separator. There are several overloaded versions of this method available. Aligns a string by adding spaces to the left or right of the current string instance to reach the total number of characters specified by the parameter value. Overridden versions of this method allow you to specify the padding character.

Insert(int, string)

Join(string, IEnumerable<string>)

PadLeft(int) PadRight(int)

Remove(int) Remove(int, int)

Creates a new string by removing characters from the current string instance. The first version of this method deletes characters from the index specified by the int parameter through to the end of the string. The second version deletes the number of characters specified by the second int parameter, starting at the index specified by the first int parameter. The first version of this method replaces every instance of the first char parameter with the second char parameter. The second version of this method does the same thing, but for the sequences of characters contains in the string parameters. Returns a string array that contains the substrings of the current string that are delimited by any of the parameter characters. Overridden versions of this method are available that allow strings to be split using different criteria. Retrieves a subrange of characters from the current string. The first version retrieves the characters from the index specified by the Int parameter to the end of the string. The second version retrieves the number of characters specified by the second parameter starting from the index specified by the first parameter. Converts the current string instance to uppercase or lowercase.

Replace(char, char) Replace(string, string)

Split(params char[])

Substring(int) Substring(int, int)

ToUpper() ToLower() TrimStart() TrimEnd() Trim()

Removes any whitespace characters from the start (TrimStart), end (TrimEnd), or start and end (Trim) of the current string instance.

Listing 16-14 contains a demonstration of some of these methods. Listing 16-14. Using System.String Methods to Manipulate Strings using System; class Listing 14 { static void Main(string[] args) { // define some strings string firstString = "Introduction"; string secondString = "to"; string thirdString = "C#"; // concat the strings string concatString = String.Concat(firstString, secondString, thirdString); // write out the concatenated value

Console.WriteLine("Concat: {0}", concatString); // insert some spaces into the string string insertString = concatString.Insert(12, " "); insertString = insertString.Insert(15, " "); // write out the modified string Console.WriteLine("Insert: {0}", insertString); // define an array of strings string[] strArray = {"Introduction", "to", "C#"}; // join the strings together using space as a separator string joinString = String.Join(" ", strArray); // write out the modified string Console.WriteLine("Join: {0}", joinString); // pad the string string padString = joinString.PadLeft(25); // write out the modified string Console.WriteLine("Pad: -{0}-", padString); // remove some characters string removeString = joinString.Remove(12); // write out the modified string Console.WriteLine("Remove: {0}", removeString); // replace some characters string replaceString = removeString.Replace('o', '0'); // write out the modified string Console.WriteLine("Replace: {0}", replaceString); // split a string an enumerate the contents string splitString = "Introduction to C#"; string[] strElements = splitString.Split(' '); foreach (string s in strElements) { Console.WriteLine("Element: {0}", s); } // force a string into uppoer and lowe case string upperString = splitString.ToUpper(); string lowerString = splitString.ToLower(); // write out the modified strings Console.WriteLine("Upper: {0}", upperString); Console.WriteLine("Lower: {0}", lowerString); // wait for input before exiting Console.WriteLine("Press enter to finish"); Console.ReadLine(); } } Compiling and running Listing 16-14 produces the following results: