 Text File Operations VB.NET |
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 Jun 26 2005, 09:20 PM
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#1
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Member [ Level 1 ]  Group: Members Posts: 35 Joined: 10-June 05 Member No.: 6,038  |
In this tutorial you will learn most of the operations you can use on a
text file. They include finding if a file exists, opening/creating a file, reading/writing file, closing file, copying file, deleting file. You will need a form with two buttons on it. Use the names Step1 and Step2. First thing we are going to do is import system.IO. To do this go into the forms code view. At the very top add this line. CODE Imports system.IO This lets us use the file operations that we need for this tutorial. Next we need to check to see if a file exists. To do this double click on the step1 button and type this code. CODE If File.Exists("TextFile.txt") then This line just checks if the file already exists. Next type this line of code. CODE Dim ioFile as new StreamReader("TextFile.txt") This line of code opens "TextFile.txt" for reading. Now we are going to read the file and store it into a variable. CODE Dim ioLine as string ' Going to hold one line at a time Dim ioLines as string ' Going to hold whole file ioLine = ioFile.ReadLine ioLines = ioLine While not ioLine = "" ioLine = ioFile.ReadLine ioLines = ioLines & vbcrlf & ioLine End While We now have the whole text file read into ioLines. Lets display the text in a message box. CODE MsgBox(ioLines) Now we are going to close the file. CODE ioFile.close Now that we are done reading a file. Lets do the else statement of the if File.Exists statement. The way this code is going to be set-up is if the file exists the program reads it. If it doesn't exist it writes a file. CODE Else Dim ioFile as new StreamWriter("TextFile.txt") We now have a file open for writting. Lets write two lines to it. CODE ioFile.WriteLine("Hi There") ioFile.WriteLine("User") So we have some text in the file now. Lets close the file. CODE ioFile.Close We are done with reading/writting files so lets end the if statement CODE End If That is it for that button. Now lets move onto deleteing files. Go back to form view and double click on the second button. In the code add these lines. CODE If File.Exists("TextFile.txt") File.Delete("TextFile.txt") else msgbox("File doesn't exist") end if All this code does is check for the file then if it exists deletes it. If it doesn't exist then it tells the user that it doesn't exist. Thats it for this tutorial. Thanks, Rich |
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Aug 10 2005, 06:59 PM
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#2
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Newbie [ Level 2 ] Group: Members Posts: 10 Joined: 10-August 05 Member No.: 7,750 |
another valuable concept to learn to work with text file is the stream class. It is especially useful for reading files from over the internet.
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Mar 17 2008, 04:18 PM
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#3
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Newbie [ Level 2 ] Group: Members Posts: 13 Joined: 17-March 08 Member No.: 29,189 |
You can use:
CODE Dim path As String Dim returnValue As String path = "1.txt" returnValue = TextBox1.Text File.WriteAllText(path, returnValue) And write: CODE Dim path As String
Dim returnValue As String path = "1.txt" returnValue = File.ReadAllText(path) TextBox1.Text = returnValue |
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Apr 23 2008, 10:54 AM
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#4
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Newbie [ Level 1 ] Group: Members Posts: 0 Joined: 1-November 07 Member No.: 25,869 |
multi lines in text file
Text File Operations VB.NET I can write one line in a text file how I can write multi lines in a text file using vb.Net -question by arif |
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Apr 29 2008, 07:40 AM
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#5
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Newbie [ Level 1 ] Group: Members Posts: 0 Joined: 1-November 07 Member No.: 25,869 |
how to add a new line to the end of an existing file
Text File Operations VB.NET How to add a new line to the end of an existing file -reply by rokesh |
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Jun 14 2008, 05:42 PM
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#6
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Newbie [ Level 1 ] Group: Members Posts: 0 Joined: 1-November 07 Member No.: 25,869 |
How can i search string or text in file content
Text File Operations VB.NET I need to build application similar to windows desktop search. I need to search text or string in file name and inside file content. And stop the search through stop button. Can you help me with this? -reply by Beginner |
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Lo-Fi Version | Time is now: 6th September 2008 - 05:18 PM |