HOW TO：使用 SaveFileDialog 元件儲存檔案

發行項
08/21/2008

更新：2007 年 11 月

SaveFileDialog 元件可讓使用者瀏覽檔案系統，然後選取要儲存的檔案。對話方塊會傳回使用者在對話方塊選取的檔案名稱與路徑。然而，您必須撰寫程式碼，才能將檔案寫入磁碟。

若要使用 SaveFileDialog 元件儲存檔案

顯示 [儲存檔案] 對話方塊，然後呼叫方法儲存使用者選取的檔案。

使用 SaveFileDialog 元件的 OpenFile 方法儲存檔案。這個方法提供您可以寫入的 Stream 物件。

下列範例使用 DialogResult 屬性取得檔案名稱，並使用 OpenFile 方法儲存檔案。OpenFile 方法提供寫入檔案的資料流。

在下列範例中，Button 控制項具有指定的影像。按一下按鈕時，SaveFileDialog 元件會藉由允許 .gif、.jpeg 和 .bmp 檔案類型的篩選常式具現化。如果在 [儲存檔案] 對話方塊中選取這種類型的檔案，就會儲存按鈕的影像。

安全性注意事項：
若要取得或設定 FileName 屬性，組件需要 System.Security.Permissions.FileIOPermission 類別授與的權限層級。如果您正在部分信任的內容中執行動作，則會因權限不足而導致處理序擲回例外狀況。如需詳細資訊，請參閱程式碼存取安全性的基本概念。

這個範例假設您的表單具有 Button 控制項，而且其 Image 屬性設定為 .gif、.jpeg 或 .bmp 的檔案類型。

注意事項：
FileDialog 類別的 FilterIndex 屬性 (由於繼承的關係，而成為 SaveFileDialog 類別的一部分) 使用以一起始的索引。如果撰寫程式碼，以特定格式儲存資料 (例如以純文字與二進位的格式儲存檔案)，這個屬性就非常重要。以下範例將說明這個屬性的功能。

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 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.set_Filter("JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif");
   saveFileDialog1.set_Title("Save an Image File");
   saveFileDialog1.ShowDialog();

   // If the file name is not an empty string open it for saving.
   if (saveFileDialog1.get_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.get_FilterIndex())
      {
         case 1:
            this.button2.get_Image().Save(fs,
               System.Drawing.Imaging.ImageFormat.get_Jpeg());
            break;

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

         case 3:
            this.button2.get_Image().Save(fs,
               System.Drawing.Imaging.ImageFormat.get_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#、Visual J# 和 Visual C++) 將下列程式碼加入表單的建構函式以註冊事件處理常式。

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

this.button2.add_Click(new System.EventHandler(this.button2_Click));

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

如需寫入檔案資料流的詳細資訊，請參閱 FileStream.BeginWrite 方法和 FileStream.Write 方法。

注意事項：
特定控制項 (例如 RichTextBox 控制項) 能夠儲存檔案。如需詳細資訊，請參閱 MSDN Online Library 技術文件 Essential Code for Windows Forms Dialog Boxes 的＜SaveFileDialog Component＞一節。

共用方式為

HOW TO：使用 SaveFileDialog 元件儲存檔案

若要使用 SaveFileDialog 元件儲存檔案

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