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VB and C# Programming Basics Overview • • • • • Basic operations String processing Date processing Control structures Functions and subroutines Additional Documentation • For extensive documentation in Microsoft .NET Development using VB or C#: – http://msdn.microsoft.com/en-us/library/dd642420.aspx The System Namespace • Contains fundamental classes, including String and DateTime • System Namespace Documentation – http://msdn.microsoft.com/enus/library/system.aspx String Processing • • • • • Concatenation String length Substrings Changing case Replacing text • Hyperlink to String class documentation String concatenation Note: C# is case sensitive. Length property begins with upper-case “L” Returning string lengths Substring method of String class. 1st argument = start position 2nd (optional) argument = length of substring Indexof method of String class Returns the 0-based index position of the substring in the searched string. Syntax: searchedString.Indexof (stringToFind) searchedString.Indexof (stringToFind, startPos) Changing case Replacing text in a string The DateTime Class • Provides many useful properties and methods related to dates and times • Hyperlink to DateTime documentation Date Manipulation Lots of methods and properties for the DateTime class! Additional Notes • In C#, use DateTime.Parse static method to convert a string to date. Not necessary in VB. – Try changing from DateTime.Now to a string representing a date and time • To make the view source more readable, you can insert line breaks in your output string: – “\n” for C# – ControlChars.CrLf for VB Control Structures • Selection – if – else – select case ----- switch • Looping – for loops – while and do while loops Syntax for if statements in C# is identical to what you know from Java VB Select-Case like before Note: C# switch statement allows case to include strings…different from Java, which requires integral values for loop syntax similar to what you know of Java Note: unlike Java, C# includes a foreach keyword in the core language. while in C# is similar to what you know already in Java Functions and Subroutines • Signatures – return type, name, parameter list • Calling functions and subroutines • Making use of return values Note: with VB .NET, explicit type declarations not necessary Note the use of ToString method…converts numeric values to strings for text output. Note that the int data type (and other primitive data types) provides the possibility of converting data to string via ToString(). In this sense it operates like a Java wrapper class. Array Processing • Topics: – – – – Array declaration, instantiation, initialization Single-dimensional arrays Multi-dimensional arrays Jagged arrays Single Dimension Arrays C# Declaration in C# is strict, brackets must follow data type: int[] array1; NOT int array1[]; Looping through arrays can be done using Length property or via for each loop Single Dimension Arrays VB Multi Dimension Arrays C# Multi-dimension array declaration and use in C# is unlike Java. With Java you are always declaring jagged arrays, but C# has a feature for multi-dimension arrays Multi Dimension Arrays VB Length vs. GetLength(): Length returns full array size GetLength(x) returns nbr elements in row x Jagged Arrays C# Jagged arrays are familiar to Java programmers Jagged Arrays VB Web Server Controls for Assignment #1 • TextBox – Two Useful Properties: • Text – contains the string for user input • Columns – specifies visible number of characters • Button – Event processing via ONCLICK attribute in ASP:Button tag • Label – Static text display Note initialization of server control properties in the Page_Load procedure Association of click event with event-handling routine Resulting HTML code Resulting browser render The web.config file • • • • • • • Useful for deployment and configuration Primarily for web administration Can also be used for creating global application variables XML file If used, should be placed in application’s root folder For debugging purposes, you should do the following…… In your web.config file, change the tag that says: – <customErrors mode="RemoteOnly" /> • To – <customErrors mode="Off"/> • This will enable compile errors in your code to be identified when attempting to view the page in a browser