How to Write Data to a Text File using C#

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In this tutorial, i will teach you how to create a program that writes data to a text file using C#. This is my continuation of my other tutorial entitled How to Read Data from a Text File using C#.

Now, let's start this tutorial!

1. Let's start with creating a Windows Form Application in C# for this tutorial by following the following steps in Microsoft Visual Studio: Go to File, click New Project, and choose Windows Application.

2. Next, add only one Button named btnSave and labeled it as "Save". Insert also one textbox named txtInput for inputting a text that we will write in the text file and a SaveFileDialog named SaveFileDialog1 to save it as a text file. You must design your interface like this:

3. In your btnSave, put this code below.

Filter your saveFileDialog1 to be saved as a text file or a .txt file extension. And add also a title to this control.

1. saveFileDialog1.
   
   Filter
   
   =
   
   "Text Files|*.txt"
   
   ;
   
2. saveFileDialog1.
   
   Title
   
   =
   
   "Write Data to Text File."
   
   ;
   

Now, create a code to show the dialog in the saveFileDialog1 for saving the text file.

1. saveFileDialog1.
   
   ShowDialog
   
   (
   
   )
   
   ;
   

Initialize the System.IO.StreamWriter having a File variable. This will write data to the saveFileDialog1 filename. We used the StreamWriter for writing a data to this file of saveFileDialog1.

1. System.IO
   
   .
   
   StreamWriter
   
   file =
   
   new
   
   System.IO
   
   .
   
   StreamWriter
   
   (
   
   saveFileDialog1.
   
   FileName
   
   , true
   
   )
   
   ;
   

Make a string variable named data that will hold the inputted text of txtInput.txt.

1. string
   
   data =
   
   txtInput.
   
   Text
   
   ;
   

Code for writing data to the file.

1. file.
   
   WriteLine
   
   (
   
   data)
   
   ;
   

Close your file.

1. file.
   
   Close
   
   (
   
   )
   
   ;
   

Full source code:

1. using
   
   System
   
   ;
   
2. using
   
   System.Collections.Generic
   
   ;
   
3. using
   
   System.ComponentModel
   
   ;
   
4. using
   
   System.Data
   
   ;
   
5. using
   
   System.Drawing
   
   ;
   
6. using
   
   System.Text
   
   ;
   
7. using
   
   System.Windows.Forms
   
   ;
   
8. 
   
9. namespace
   
   write_data_to_textfile_using_CSharp
   
10. {
    
11. public
    
    partial
    
    class
    
    Form1 :
    
    Form
    
12. {
    
13. public
    
    Form1(
    
    )
    
14. {
    
15. InitializeComponent(
    
    )
    
    ;
    
16. }
    
17. 
    
18. private
    
    void
    
    button1_Click(
    
    object
    
    sender, EventArgs e)
    
19. {
    
20. saveFileDialog1.
    
    Filter
    
    =
    
    "Text Files|*.txt"
    
    ;
    
21. saveFileDialog1.
    
    Title
    
    =
    
    "Write Data to Text File."
    
    ;
    
22. saveFileDialog1.
    
    ShowDialog
    
    (
    
    )
    
    ;
    
23. 
    
24. System.IO
    
    .
    
    StreamWriter
    
    file =
    
    new
    
    System.IO
    
    .
    
    StreamWriter
    
    (
    
    saveFileDialog1.
    
    FileName
    
    , true
    
    )
    
    ;
    
25. 
    
26. string
    
    data =
    
    txtInput.
    
    Text
    
    ;
    
27. 
    
28. file.
    
    WriteLine
    
    (
    
    data)
    
    ;
    
29. 
    
30. file.
    
    Close
    
    (
    
    )
    
    ;
    
31. }
    
32. }
    
33. }
    

Press F5 to run the program.


Input:

Save as sourcodester.txt.

Output:

Hope this helps! :)

Best Regards,

Engr. Lyndon Bermoy
IT Instructor/System Developer/Android Developer/Freelance Programmer

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