Shree Swaminarayan College of Computer Science. BCA-CC-404 Application Development Using VB.NET

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1 SDI V/S. MDI Shree Swaminarayan College of Computer Science SDI It is stands for Single Document Interface. User can open from in SDI. It is known as parent form. In SDI form user can place only control as per is requirement. We can include or add more then one SDI form in single project. We can include or add more then one SDI form in single project. It does not support arrage method. It has MDI child properly. For ex:-notepad MDI It is stands for Multiple Document Interface. User can open more then one form in MDI. It is known as child form. In MDI only those control which has aline property. In MDI only those control which has aline property. We can include or add only one MDI form in single project. It can support arrage method. It does not have MDI child properly. For ex:-microsoft word MODAL VS/ MODLESS DIALOG Forms and dialog boxes are either modal or modeless. A model form requires the user to supply information or cancel or hide the dialog box, before allowing the application to continue. Modal dialog does not allow its parent window unless it is closed. A modeless form allows the user to supply information and return to the previous task without closing the dialog box. We can navigate between the forms in modeless. Example for model form is Save, Save As Dialog in MS-Excel While it is opening we can t do any thing in the application until we close that window. Example for modeless form is Find, Replace dialogs. We can use Find Dialog, same time you can also work in the word application. Dialog boxes that display important messages must be modal. MessageBox and InputBox are a modal form. Check it practically to switch over parent form. We can listen Beep. We can not switch over to parent form until we close that dialog box. Modeless forms we can jump or shift the focus between the form and another form without having to close initial form. Parallely we can work with multiple forms. We can continue to work elsewhere in any application while the form is displayed. Modeless forms are difficult to manage, because users can access them in an unpredictable order. PREPARED BY: NIRAV K. SHAH, Year Page 1 of 8

2 Type Checking Function Vb.Net.Net provides number of data verification or data type checking functions as under 1. IsDate Return True Or False. If input by user is date then return true otherwise false. Dim dt as Date, Dim bool as Boolean dt = March 31, 2010 bool = IsDate(dt) MsgBox(bool) //Return True 2. IsNothing Return true if the object variable that currently has no assigned value otherwise false. Dim bool As Boolean, Dim obj As Object bool = IsNothing(obj) MsgBox(bool) //Return True 3. IsNumeric Return True if the value is numeric otherwise false Dim no As Object, Dim bool As Boolean no = 31 bool = IsNumeric(no) MsgBox(bool) //Return True 4. ISDBNull ISDBNull returns true if the value evaluates to the DBNull otherwise, return false. The System.DBNull value indicates that the object represents or nonexistent data. DBNull is not the same as nothing or null string Dim obj As Object, Dim bool As Boolean Bool = ISDBNull(obj) MsgBox(bool) //Return False 5. IsArray : Return if the variable is declare as an array otherwise false PREPARED BY: NIRAV K. SHAH, Year Page 2 of 8

3 InBuilt Function 1. Length It returns the length of the string Dim str As String Str = SSCCS Ans = str.length() OR ans = Len(str) 2. Compare It s compare two strings I = str.compare( SSCCS, ssccs,true) MsgBox(I,MsgBoxStyle.Information, Comparison ) 3. Concate We can contact two string with this function We also use +, & operator to concate two string Ans = String.Concat( Welcome To, SSCCS ) 4. Copy Copy string from source to destination Dim str As string = SSCCS Dim str1 As string = Welcome To SSCCS Str1 = String.Copy(str) MsgBox(str1) 5. Equals Determine whether two string have the same value or not. Return Boolean value MsgBox(String.Equals( SSCCS, SSCCS ) 6. TRIM Remove starting and ending space from the string and ending of the string by default. Str = SSCCS MsgBox(str.Length) //Count the string length MsgBox(str.Trim(str)) Dim str as string Ans = ) 7. Ucase Convert to Upper Case ( Capital ) PREPARED BY: NIRAV K. SHAH, Year Page 3 of 8

4 MsgBox(Ucase( ssccs )) 8. Lcase Convet to Lower Case ( small ) MsgBox(Lcase( SSCCS )) 9. ToUpper Convert to Upper Case ( Capital ) Dim str as string = ssccs Ans = str.toupper() 10. ToLower Convet to Lower Case ( small ) Dim str as string = SSCCS Ans = str.tolower() 11. Insert Insert a specified instance of string at a specified index position in this instance. Str = Welcome To Str = str.insert(10, SSCCS ) 12. PadLeft Used to input the value to the string at left position Str = Hello Str = ) 13. PadRight Used to input the value to the string at Rigth position Str = Hello Str = ) 14. Remove Delete a specified number of characters from this instance beginning at a specified position. Two argument of this function (StartIndex, Count) StartIndex means the positon in this instance to being deleting characters and count means the number of characters to delete. Str = Welcome to SSCCS PREPARED BY: NIRAV K. SHAH, Year Page 4 of 8

5 Str = str.remove(5,8) Msgbox(str) 15. Replace Replace occurance of specified character with new character Str = Animal Str = str.replace( A, E ) 16. Substring Retrieve a substring from this instance There are two argument(startindex,count) Str= Welcome to SSCCS Str = str.substring(11,5) 17. Split Returns one-dimensional array containing a specified number of substrings. By default it is split by space. We also define our character to split string like this : Split( Welcome,To,SSCCS,, ) Dim temp() as string = Split( Welcome To SSCCS ); MsgBox(temp(0)) MsgBox(temp(1)) MsgBox(temp(2)) 18. Join Return a string created by a array in a single string Dim temp() As String = { Welcome, To, SSCCS } Str = Join(temp,, ) 19. IIF Returns one of two objects, depending on the evaluation of an expression. It is like ternary operator in c & c++. Syntax IIF(Expression,Truepart,Falsepart) Dim I as integer = 5 Str = IIF(I>5, Good, Bad ) MsgBox(Str) 20. Mid Returns a string containing a specified number of characters from a string. Name = Shah Amit Kiritbhai PREPARED BY: NIRAV K. SHAH, Year Page 5 of 8

6 Str1 = Mid(name,1,4) Str2 = Mid(name,6,4) Str3 = Mid(name,11,9) MsgBox( str1 + + str2 + + str3) 21. StrReverse Return a reverse of string character Str = SSCCS Str = StrReverse(str) 22. ASC Return a Ascii value of string Dim ans As Integer Ans = Asc( a ) //Return CHR Return a character associated with the ascii value. Dim c as char MsgBox(Chr(97)) //Return a 24. SendKeys It provide methods for sending keystrokes to an application..send is the method of sendkeys class to send particular value to an application. 25. Date Time Function Returns a date time by specific function Txtdt.Text = Now Txtdt.Text = Today Txtdt.Text = TimeOfDay Txtdt.Text = TimeString 26. Format Function Returns a string formatted according to instruction contained in a format string expression. Txtdt.Text = Format(Now, M-d-yy ) Txtdt.Text = Format(Now, MM-dd-yyyy ) Txtdt.Text = Format(Now, MMMM-d-yyy - dddd ) Txtdt.Text = Format(Now, hh:mm:ss tt ) 27. Math Function Returns the math value by inbuilt function To use math function import System.Math before used it. PREPARED BY: NIRAV K. SHAH, Year Page 6 of 8

7 Ans = Sqrt(36) Ans = Round( ) Ans = Truncate( ) Ans = Abs(-125) Ans = Math.Pow(5,2) //Return 25 UNIVERSITY QUESTION & ITS ANSWER Q-Explain.NET Assembly in detail Answer : Defination : The 'Assembly' is a new concept that the.net framework introduces to make your journey in programming more easier. The.NET framework introduces assemblies as the main building blocks of your application. An application can contains one or more assemblies. An assembly can be formed in one or more files. This all depends on your programming needs. An assembly can consist of the following four elements: 1. Your code, compiled into MS intermediate language (MISL). This code file can be either an EXE file or a DLL file. 2. The assembly manifest, which is a collection of metadata that describes assembly name, culture settings, list of all files in the assembly, security identity, version requirements, and references to resources. The assembly manifest can be stored with the intermediate code, or in a standalone file that contains only assembly manifest information. 3. Type metadata 4. Resources The main and only required element of the above four elements is the assembly manifest. The remaining elements are optional depending on your requirements. As we have mentioned above, an assembly can be formed into a single physical file. In this case all the above four elements will be stored inside this file (either an EXE, or a DLL file). Or it can be formed in more than one file, and in this later case we call it a multi-file assembly. In multifile assembly the above four elements can be stored in separate files like module files for code, resources files for images, or other files required by the application. Note that the files that forms the multi-file assembly are not physically linked, instead they are linked through the assembly manifest. You may ask yourself, when should I use multi-file assembly technique? The answer is, you should use this form of assembly when you want to combine modules written in different languages, when you want to optimize downloading an application that consists of more than one module, or when you want to use a huge resource file so you put it in a separate resource file and the.net framework will download it only when it is referenced which will optimize your memory usage and system resources. PREPARED BY: NIRAV K. SHAH, Year Page 7 of 8

8 How Does It Work? you may recall that an assembly manifest contains the versioning requirements of the current assembly. The version of the assembly and the versions of the required assemblies and/or components are recorded in the manifest. So, when you run an application, the.net runtime checks the assembly manifest of your application and executes the version of assemblies or components that are recorded in the manifest. To gain the advantages of versioning you must give your assembly a strong name In short: An assembly is a collection of types and resources that forms a logical unit of functionality. When you compile an application, the MSIL code created is stored in an assembly. Assemblies include both executable application files that you can run directly from Windows without the need for any other programs (these have a.exe file extension), and libraries (which have a.dll extension) for use by other applications. There are two kind of assemblies in.net; private shared Private assemblies are simple and copied with each calling assemblies in the calling assemblies folder. Shared assemblies (also called strong named assemblies) are copied to a single location (usually the Global assembly cache). For all calling assemblies within the same application, the same copy of the shared assembly is used from its original location. Hence, shared assemblies are not copied in the private folders of each calling assembly. Each shared assembly has a four part name including its face name, version, public key token and culture information. The public key token and version information makes it almost impossible for two different assemblies with the same name or for two similar assemblies with different version to mix with each other. PREPARED BY: NIRAV K. SHAH, Year Page 8 of 8