How to: Save Files Using the SaveFileDialog Component

Article
11/16/2012

The SaveFileDialog component allows users to browse the file system and select files to be saved. The dialog box returns the path and name of the file the user has selected in the dialog box. However, you must write the code to actually write the files to disk.

To save a file using the SaveFileDialog component

Display the Save File dialog box and call a method to save the file selected by the user.

Use the SaveFileDialog component's OpenFile method to save the file. This method gives you a Stream object you can write to.

The example below uses the DialogResult property to get the name of the file, and the OpenFile method to save the file. The OpenFile method gives you a stream to write the file to.

In the example below, there is a Button control with an image assigned to it. When you click the button, a SaveFileDialog component is instantiated with a filter that allows files of type .gif, .jpeg, and .bmp. If a file of this type is selected in the Save File dialog box, the button's image is saved.

Security Note:
To get or set the FileName property, your assembly requires a privilege level granted by the System.Security.Permissions.FileIOPermission class. If you are running in a partial-trust context, the process might throw an exception due to insufficient privileges. For more information, see Code Access Security Basics.

The example assumes your form has a Button control with its Image property set to a file of type .gif, .jpeg, or .bmp.

Note

The FileDialog class's FilterIndex property (which, due to inheritance, is part of the SaveFileDialog class) uses a one-based index. This is important if you are writing code to save data in a specific format (for example, saving a file in plain text versus binary format). This property is featured in the example below.

Private Sub Button2_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button2.Click
   ' Displays a SaveFileDialog so the user can save the Image
   ' assigned to Button2.
   Dim saveFileDialog1 As New SaveFileDialog()
   saveFileDialog1.Filter = "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif"
   saveFileDialog1.Title = "Save an Image File"
   saveFileDialog1.ShowDialog()

   ' If the file name is not an empty string open it for saving.
   If saveFileDialog1.FileName <> "" Then
      ' Saves the Image via a FileStream created by the OpenFile method.
      Dim fs As System.IO.FileStream = Ctype _
         (saveFileDialog1.OpenFile(), System.IO.FileStream)
      ' Saves the Image in the appropriate ImageFormat based upon the
      ' file type selected in the dialog box.
      ' NOTE that the FilterIndex property is one-based.
      Select Case saveFileDialog1.FilterIndex
         Case 1
            Me.button2.Image.Save(fs, _
               System.Drawing.Imaging.ImageFormat.Jpeg)

         Case 2
            Me.button2.Image.Save(fs, _
               System.Drawing.Imaging.ImageFormat.Bmp)

         Case 3
            Me.button2.Image.Save(fs, _
               System.Drawing.Imaging.ImageFormat.Gif)
       End Select

       fs.Close()
    End If
End Sub

private void button2_Click(object sender, System.EventArgs e)
{
   // Displays a SaveFileDialog so the user can save the Image
   // assigned to Button2.
   SaveFileDialog saveFileDialog1 = new SaveFileDialog();
   saveFileDialog1.Filter = "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif";
   saveFileDialog1.Title = "Save an Image File";
   saveFileDialog1.ShowDialog();

   // If the file name is not an empty string open it for saving.
   if(saveFileDialog1.FileName != "")
   {
      // Saves the Image via a FileStream created by the OpenFile method.
      System.IO.FileStream fs = 
         (System.IO.FileStream)saveFileDialog1.OpenFile();
      // Saves the Image in the appropriate ImageFormat based upon the
      // File type selected in the dialog box.
      // NOTE that the FilterIndex property is one-based.
      switch(saveFileDialog1.FilterIndex)
      {
         case 1 : 
         this.button2.Image.Save(fs, 
            System.Drawing.Imaging.ImageFormat.Jpeg);
         break;

         case 2 : 
         this.button2.Image.Save(fs, 
            System.Drawing.Imaging.ImageFormat.Bmp);
         break;

         case 3 : 
         this.button2.Image.Save(fs, 
            System.Drawing.Imaging.ImageFormat.Gif);
         break;
      }

   fs.Close();
   }
}

private:
   System::Void button2_Click(System::Object ^ sender,
      System::EventArgs ^ e)
   {
      // Displays a SaveFileDialog so the user can save the Image
      // assigned to Button2.
      SaveFileDialog ^ saveFileDialog1 = new SaveFileDialog();
      saveFileDialog1->Filter = 
         "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif";
      saveFileDialog1->Title = "Save an Image File";
      saveFileDialog1->ShowDialog();
      // If the file name is not an empty string, open it for saving.
      if(saveFileDialog1->FileName != "")
      {
         // Saves the Image through a FileStream created by
         // the OpenFile method.
         System::IO::FileStream ^ fs = 
            safe_cast<System::IO::FileStream*>(
            saveFileDialog1->OpenFile());
         // Saves the Image in the appropriate ImageFormat based on
         // the file type selected in the dialog box.
         // Note that the FilterIndex property is one based.
         switch(saveFileDialog1->FilterIndex)
         {
            case 1 :
               this->button2->Image->Save(fs,
                  System::Drawing::Imaging::ImageFormat::Jpeg);
               break;
            case 2 :
               this->button2->Image->Save(fs, 
                  System::Drawing::Imaging::ImageFormat::Bmp);
               break;
            case 3 :
               this->button2->Image->Save(fs, 
                  System::Drawing::Imaging::ImageFormat::Gif);
               break;
         }
      fs->Close();
      }
   }

(Visual C# and Visual C+) Place the following code in the form's constructor to register the event handler.

this.button2.Click += new System.EventHandler(this.button2_Click);

this->button2->Click += gcnew
   System::EventHandler(this, &Form1::button2_Click);

For more information about writing file streams, see FileStream.BeginWrite Method and FileStream.Write Method.

Note

Certain controls, such as the RichTextBox control, have the ability to save files. For more information, see the "SaveFileDialog Component" section of the MSDN Online Library technical article, Essential Code for Windows Forms Dialog Boxes.

How to: Save Files Using the SaveFileDialog Component

To save a file using the SaveFileDialog component

See Also

Reference

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