Today in C#, I will teach you how to create a program that will convert an image to its file extension in jpeg, bmp, png, and gif.

Now, let's start this tutorial!

1. Let's start with creating a Windows Form Application for this tutorial by following the following steps in Microsoft Visual Studio 2010: Go to File, click New Project, and choose Windows Application.

2. Next, add one PictureBox named picbox, two buttons named btnBrowse and btnconvert, and one ComboBox named cbformats. Add two dialogs named saveDialog as saveFileDialog, and OFDialog as o You must design your interface like this:



3. Click the Items property of your cbformats and encode PNG, BMP, GIF, and JPEG.

4. In your form_load() put this code below:

1. public
   
   void
   
   Form1_Load(
   
   System
   
   .
   
   Object
   
   sender, System
   
   .
   
   EventArgs
   
   e)
   
2. {
   
3. cbformats.
   
   SelectedItem
   
   =
   
   "PNG"
   
   ;
   
4. }
   
5. 
   

.
5. In your btnbrowse put this code below so that it can browse image files.

1. public
   
   void
   
   btnbrowse_Click(
   
   System
   
   .
   
   Object
   
   sender, System
   
   .
   
   EventArgs
   
   e)
   
2. {
   
3. 
   
4. try
   
5. {
   
6. // when the Browse Image button is click it will open the OpenfileDialog
   
7. //this line of will check if the dialogresult selected is cancel then
   
8. if
   
   (
   
   OFDialog.
   
   ShowDialog
   
   (
   
   )
   
   !=
   
   System
   
   .
   
   Windows
   
   .
   
   Forms
   
   .
   
   DialogResult
   
   .
   
   Cancel
   
   )
   
9. {
   
10. //the the selected image speciied by the user will be put into out picturebox
    
11. picbox.
    
    Image
    
    =
    
    Image.
    
    FromFile
    
    (
    
    OFDialog.
    
    FileName
    
    )
    
    ;
    
12. //then the image sizemode is set to strectImage
    
13. picbox.
    
    SizeMode
    
    =
    
    PictureBoxSizeMode.
    
    StretchImage
    
    ;
    
14. //then we assign val in to true because val variable above is declare as boolean
    
15. val =
    
    true
    
    ;
    
16. }
    
17. }
    
18. catch
    
    (
    
    Exception ex)
    
19. {
    
20. MessageBox.
    
    Show
    
    (
    
    ex.
    
    Message
    
    )
    
    ;
    
21. }
    
22. }
    
23. 
    
24. 
    

6. In your btnconvert, put this code below to convert the images with its format.

1. public
   
   void
   
   btnconvert_Click(
   
   System
   
   .
   
   Object
   
   sender, System
   
   .
   
   EventArgs
   
   e)
   
2. {
   
3. try
   
4. {
   
5. //it check if the variable val is set to val
   
6. if
   
   (
   
   val ==
   
   true
   
   )
   
7. {
   
8. //check if what format is selected by user in the combobox
   
9. //the after this the program will convert it to the desired format by the user.
   
10. if
    
    (
    
    (
    
    string
    
    )
    
    cbformats.
    
    SelectedItem
    
    ==
    
    "PNG"
    
    )
    
11. {
    
12. saveDialog.
    
    Filter
    
    =
    
    "PNG|*.png"
    
    ;
    
13. if
    
    (
    
    saveDialog.
    
    ShowDialog
    
    (
    
    )
    
    !=
    
    System
    
    .
    
    Windows
    
    .
    
    Forms
    
    .
    
    DialogResult
    
    .
    
    Cancel
    
    )
    
14. {
    
15. picbox.
    
    Image
    
    .
    
    Save
    
    (
    
    saveDialog.
    
    FileName
    
    , System.Drawing
    
    .
    
    Imaging
    
    .
    
    ImageFormat
    
    .
    
    Png
    
    )
    
    ;
    
16. }
    
17. 
    
18. }
    
19. else
    
    if
    
    (
    
    (
    
    string
    
    )
    
    cbformats.
    
    SelectedItem
    
    ==
    
    "JPEG"
    
    )
    
20. {
    
21. saveDialog.
    
    Filter
    
    =
    
    "JPEG|*.jpg"
    
    ;
    
22. if
    
    (
    
    saveDialog.
    
    ShowDialog
    
    (
    
    )
    
    !=
    
    System
    
    .
    
    Windows
    
    .
    
    Forms
    
    .
    
    DialogResult
    
    .
    
    Cancel
    
    )
    
23. {
    
24. picbox.
    
    Image
    
    .
    
    Save
    
    (
    
    saveDialog.
    
    FileName
    
    , System.Drawing
    
    .
    
    Imaging
    
    .
    
    ImageFormat
    
    .
    
    Jpeg
    
    )
    
    ;
    
25. }
    
26. }
    
27. else
    
    if
    
    (
    
    (
    
    string
    
    )
    
    cbformats.
    
    SelectedItem
    
    ==
    
    "BMP"
    
    )
    
28. {
    
29. saveDialog.
    
    Filter
    
    =
    
    "BMP|*.bmp"
    
    ;
    
30. if
    
    (
    
    saveDialog.
    
    ShowDialog
    
    (
    
    )
    
    !=
    
    System
    
    .
    
    Windows
    
    .
    
    Forms
    
    .
    
    DialogResult
    
    .
    
    Cancel
    
    )
    
31. {
    
32. picbox.
    
    Image
    
    .
    
    Save
    
    (
    
    saveDialog.
    
    FileName
    
    , System.Drawing
    
    .
    
    Imaging
    
    .
    
    ImageFormat
    
    .
    
    Bmp
    
    )
    
    ;
    
33. }
    
34. }
    
35. else
    
    if
    
    (
    
    (
    
    string
    
    )
    
    cbformats.
    
    SelectedItem
    
    ==
    
    "GIF"
    
    )
    
36. {
    
37. saveDialog.
    
    Filter
    
    =
    
    "GIF|*.gif"
    
    ;
    
38. if
    
    (
    
    saveDialog.
    
    ShowDialog
    
    (
    
    )
    
    !=
    
    System
    
    .
    
    Windows
    
    .
    
    Forms
    
    .
    
    DialogResult
    
    .
    
    Cancel
    
    )
    
39. {
    
40. picbox.
    
    Image
    
    .
    
    Save
    
    (
    
    saveDialog.
    
    FileName
    
    , System.Drawing
    
    .
    
    Imaging
    
    .
    
    ImageFormat
    
    .
    
    Gif
    
    )
    
    ;
    
41. }
    
42. }
    
43. }
    
44. }
    
45. catch
    
    (
    
    Exception ex)
    
46. {
    
47. MessageBox.
    
    Show
    
    (
    
    ex.
    
    Message
    
    )
    
    ;
    
48. }
    
49. }
    

Sample output:


Best Regards,

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

If you have some queries, feel free to contact the number or e-mail below.
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