Visual Basic. NET programming for Beginners. The ability to open up a text file and read its contents can be very useful. You might have a text file containing quiz. You could read the questions and answers. Who wants to be a Millionaire. Or you might want to save some data associated with your programme, and. Well see how to open up a text. VB. NET right now. To open up a text file, you need to create something called a StreamReader. This, as its name suggests, reads streams of text. The StreamReader is an object. Here Mudassar Ahmed Khan has explained how to read or extract text from image using Microsoft Office Document Imaging MODI in ASP. Net with C and VB. Net. This. Quick reference guide that compares VB. NET and C. Here Mudassar Ahmed Khan has explained with an example, how to upload, read and display CSV file Text File data in ASP. Net GridView using C and VB. Net. CSV file is. In a later section, youll learn how to save data. To open up a text file, you need to create something called a Stream. Reader. This, as its name suggests, reads streams of text. The Stream. Reader is an object. System. IO. Visual Studio 2. System. part. This applies for all the code in this text files section. You create. Stream. Reader like this Dim FILENAME As String C UsersOwnerDocumentstest. Dim obj. Reader As New System. IO. Stream. Reader. FILENAME The first line just sets up a string variable called FILENAME. We store the. path and name of our text file inside of the string variable C UsersOwnerDocumentstest. Were saying that there is a text file called test which is at the location. C. You set up the Stream. Reader to be a variable, just like a String or. Integer variable. But were setting up this variable differently Dim obj. Reader As New System. IO. Stream. Reader. FILENAME Weve called the variable obj. Reader. Then, after the As. New. This means Create a New Object. The type of object we want to create is a Stream. Reader object System. IO. Stream. Reader. Sysytem is the main object. P8MvphHOd8k.jpg' alt='How To Read Text From File In Vb.Net' title='How To Read Text From File In Vb.Net' />I am creating a program that is supposed to write text into a text file, and should be able to read specific lines from a text file in VB so if i needed to read a. XmNmDeu.png' alt='How To Read Text From File In Vb.Net' title='How To Read Text From File In Vb.Net' />IO is an object within System. And. Stream. Reader is an object within IO. Stream. Reader needs the name of a file to Read. This goes between a pair of. System. IO. Stream. Reader FILENAME VB will then assign all of this to the variable called obj. Reader. So. instead of assigning say 1. Integer variable, you are assigning a Stream. Reader. to a variable. Read To End. But this wont do you any good. We havent actually opened the text file yet. Weve just told VB where the text file is and what object to open it with. You. do the opening like this Text. Box. 1. Text obj. Reader. Read. To. End. Now that obj. Reader is an object variable, it has its own properties and methods. Text property. One of the Methods available to our new Stream. Reader variable is the Read. To. End. method. This will read the whole of your text, right to the end. Were then. popping this in a textbox. Lets test all this theory out. Do the following Start a new project Add a textbox to your new form, and just leave it on the default Name of. Textbox. 1Set its Multi. Line property to True Add a Button to your form. Double click the button and add the following code for it Dim FILENAME As String C UsersOwnerDocumentstest. Dim obj. Reader As New System. IO. Stream. Reader. FILENAME Text. Box. ZAA6baS7oZM/0.jpg' alt='How To Read Text From File In Vb.Net' title='How To Read Text From File In Vb.Net' />Text obj. Reader. Read. To. Endobj. Reader. CloseThe last line closes the Stream. Reader we set up. You have to close your stream. When youre done, run your programme and click your Button. Unless you already have a file called test. You may see this error message. Visual Studio you have. The last line spells it out clearly Could not find file C UsersOwnerDocumentstest. So we were trying to read a text file that doesnt exist. No. more reading these lessons online get the e. Book here Does the File ExistYou can, though, test to see if the file exists. If it does, you can open it. Amend your code to this the new lines. Dim FILENAME As String C UsersOwnerDocumentstest. Denmark Normal Western Font on this page. If System. IO. File. ExistsFILENAME True Then. Dim obj. Reader As New System. IO. Stream. ReaderFILENAMEText. Box. 1. Text obj. Windows Activation Code Product Key. Reader. Read. To. Endobj. Reader. CloseElse. Message. Box. ShowFile Does Not ExistEnd If Weve now wrapped up our code in an If Statement. The first line of the If. Statement is this If System. IO. File. Exists FILENAME. True Then. This tests to see whether or not a file exists. Again, you start with System. IO. Then you access another object of System. IO the File object. This has. a method called Exists. In between the round brackets, you type the name. The value returned will either. True if it does exists, or False if it doesnt. If the file exist then we can go ahead and create our Stream. Reader If it doesnt. So that your programme will work, there is a file below called test. Download this to your computer and save it to your Documents folder. Right. click the file and select Save Target As IE, or Save Link As Firefox Download the test. Text File. here. When you have done that, run your programme again. Click the button once more. If you get. the error message again, it means you havent copied the file to the right place. In the next part, well see how to read the contents line by line, instead. How to read simple text files. Written By The. VBProgramer. This tutorial describes how you can read text files in different formats and display them in your Visual Basic application. The samples here simply print the output to the main form, but this can easily be modified to do more advanced things with the text files. Req. Test. Harness. Since this tutorial uses a framework to test all the code in and sample text files it is probably easier to first Download the source code for it than follow along with the tutorial. Visual Basic provides the. Files that must be read in the same order in which they were written one after the other with no skipping aroundbinary files unstructured files which are read from or. These three file types are. Visual Basic and its predecessors QBasic, GW BASIC. The next several topics address VBs sequential file processing. Binary and Random files will be covered in later topics. The following sequential. Open. Prepares a file to be. VB program. App. Path. Supplies the path of your. Free. File. Supplies a file number. Input Reads fields from a. Line Input Reads a line up to the. EOFTests for end of file. Write Writes fields to a. Print Writes a formatted line of. Close Closes a file. As you know, a data file. The file that will be used for. Field. Data Type. Department Number. Integer. Job Title. String. Hire Date. Date. Hourly Rate. Single. Suppose there were five. A graphic representation of the file populated with the. Employee Name. Dept Job Title. Hire Date. Hourly Rate. ANDY ANDERSON1. 00. PROGRAMMER341. 99. BILLY BABCOCK1. 10. SYSTEMS ANALYST21. CHARLIE CHEESEMAN1. COMPUTER OPERATOR311. DARLENE DUNCAN2. 00. RECEPTIONIST1. 01. ERNIE EACHUS3. 00. MAIL ROOM CLERK81. Please note that the data. On the sequential file, all fields will be represented. Following are three. Notepad, this is what you might see. Scenario. 1 Comma Delimited Format. Each field is separated by a. Both string and numeric fields are trimmed contain no. String fields are enclosed in quotes Note The. VB and other applications that. The only time a string field MUST be enclosed in quotes is. If Date fields are enclosed in pound signs. VB will automatically recognize the field as the Date data type. If the. Date fields are enclosed in quotes instead, you need to use the CDate. Date data type. BILLY BABCOCK,1. SYSTEMS. ANALYST,21. CHARLIE CHEESEMAN,1. COMPUTER. OPERATOR,311. DARLENE. DUNCAN,2. RECEPTIONIST,1. ERNIE EACHUS,3. MAIL ROOM CLERK,81. Scenario. 2 Fixed Width Print FormatIn some sequential data. On each record, a particular. In a print format file, each line record of the file. In the example below, a. From the example, it should. BILLY. BABCOCK 1. SYSTEMS ANALYST 21. CHARLIE. CHEESEMAN 1. COMPUTER OPERATOR 311. DARLENE. DUNCAN 2. RECEPTIONIST 1. ERNIE. EACHUS 3. MAIL ROOM CLERK 81. Scenario. 3 Fixed Width COBOL Style Format1 1 2 2 3 3 4 4 5 5 6. BILLY. BABCOCK 0. SYSTEMS ANALYST 0. CHARLIE. CHEESEMAN 0. COMPUTER OPERATOR0. DARLENE. DUNCAN 0. RECEPTIONIST 1. ERNIE. EACHUS 0. MAIL ROOM CLERK 0. VB Statements and. Functions for Sequential File Processing. The Open Statement. The Open statement prepares. VB program. It identifies the Windows system. The. general format is Open. For mode As lt filenumber. Windows system filename, which may. Open statement. as either a string constant or a string variable. Input. Output, or Append. When a file is opened for Input, that file must. When. a file is opened for Output, if it does not exist, it will be created if it. When. a file is opened for Append, if it does not exist, it will be created, if it. The. Input and Line Input statements may only be used on files. Input mode the Write and Print may only be. Output or Append modes. Windows system filename with a number this number will be used. VB file processing statements in. Examples Open C Program. FilesEmp. MaintEMPLOYEE. DAT For Input As 1. Open. A EMPLOYEE. DAT For Input As 1. Using App. Path. In order to avoid. VB program, it is. App. Path to reference the path of the file. This way. as long as the file resides in the same directory in which your program is. For example, if both your. C Program FilesEmp. Maint, then that. App. Path would refer to. So if you concatenate App. Path with a. backslash and the name of your data file, then you have a complete reference. Open statement. Examples Open App. Path EMPLOYEE. DAT. For Input As 1. You. Dim str. Emp. File. Name As Stringstr. Emp. File. Name. App. Path EMPLOYEE. DATOpen. Emp. File. Name For Input As 1. A special situation comes up. A. If you concatenate App. Path with a backslash and the. A EMPLOYEE. DATTo cover both situations and. Dim str. Emp. File. Name As String Dim. Back. Slash As String str. Back. Slash. IIf RightApp. Path, 1, , str. Emp. File. Name. App. Path str. Back. Slash EMPLOYEE. DATUsing Free. File. In the Open statement and. For example Open str. Emp. File. Name For Input As. Emp. File. Nbr. Thus, a. Emp. File. Name As String Dim str. Back. Slash As String str. Back. Slash IIf RightApp. Path, 1 ., str. Emp. File. Name App. Path str. Back. Slash EMPLOYEE. DATOpen str. Emp. File. Name For Input As. Emp. File. Nbr. The Input. Statement. The Input statement reads. The general format is Input. Opened As. that number for Input in the Open statement. Example BILLY BABCOCK,1. SYSTEMS. ANALYST,21. CHARLIE CHEESEMAN,1. COMPUTER. OPERATOR,311. DARLENE. DUNCAN,2. RECEPTIONIST,1. ERNIE EACHUS,3. MAIL ROOM. CLERK,81. VB knows that. the data is to be read from the EMPLOYEE. DAT file because the Input. Emp. File. Nbr, and file int. Emp. File. Nbr was. EMPLOYEE. DAT in the Open statement. The EOF function. The operating system. VB can sense the presence of this end of file. EOF function. A programming language will. EOF at either one of two times 1 after the last. OR 2 at the same time that the last record. COBOL falls into the first category, VB falls into the second. FYI This discussion applies. VB processes sequential files because when VB processes the rows. EOF the COBOL way. In a language that. EOF after the last record in the file has been read such as COBOL. The pseudocode might be. READ. first RECORD DO. UNTIL EOF. READ next RECORD LOOPIn a language that. EOF when the last record is read such as VB, the input. NO PRIMING READ and. FIRST statement in the body of the processing loop. The. pseudocode might be written as follows DO. UNTIL EOF. READ A RECORD LOOPThe syntax of the EOF. EOFn where n is a number corresponding to. Free. File in the Open statement. The EOF function can be used. UNTIL, WHILE, and IF. The EOF function can also be preceded. NOT for example, Do Until EOF1 is equivalent to Do. While Not EOF1. The main loop to process the. Do Until EOFint. Emp. File. Nbr Processing for the record would go here for. Loop. Building on what has been. Dim str. Emp. File. Name As. String Dim str. Back. Slash As String str. Back. Slash IIf RightApp. Path, 1 ., str. Emp. File. Name App. Path str. Back. Slash amp. EMPLOYEE. DAT Open str. Emp. File. Name For Input As int. Emp. File. Nbr Do Until EOFint. Emp. File. Nbr Print str. Emp. Name Tab2.