如何：使用 SaveFileDialog 组件保存文件

2025-05-07

该 SaveFileDialog 组件允许用户浏览文件系统并选择要保存的文件。该对话框返回用户在对话框中选择的文件的路径和名称。但是，必须编写代码才能将文件实际写入磁盘。

使用 SaveFileDialog 组件保存文件

显示 “保存文件 ”对话框并调用方法来保存用户选择的文件。

使用SaveFileDialog组件的OpenFile方法来保存文件。此方法提供一个Stream对象，您可以对其进行写入。

下面的示例使用 DialogResult 属性获取文件的名称，以及 OpenFile 保存文件的方法。 OpenFile 方法提供一个流来写入文件。

在下面的示例中，有一个控件分配有一个 Button 图像。单击按钮时，组件将实例化为一个 SaveFileDialog 筛选器，该筛选器允许类型为 .gif、.jpeg和 .bmp的文件。如果在“保存文件”对话框中选择了此类型的文件，则会保存按钮的图像。

重要

若要获取或设置 FileName 属性，程序集需要由 System.Security.Permissions.FileIOPermission 类授予的特权级别。如果在部分信任上下文中运行，进程可能会由于权限不足而引发异常。有关详细信息，请参阅代码访问安全基础知识。

该示例假定窗体有一个 Button 控件，其 Image 属性设置为 .gif、.jpeg 或 .bmp类型的文件。

注释

SaveFileDialog类的FileDialog类的FilterIndex属性（由于继承关系，成为该类的一部分）使用一基索引。如果要编写代码以特定格式保存数据（例如，以纯文本还是二进制格式保存文件），这一点非常重要。以下示例中展示了此属性。

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# 和 Visual C++）将以下代码置于表单的构造函数中以注册事件处理程序。

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

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

有关写入文件流的详细信息，请参阅 BeginWrite 和 Write。

注释

某些控件（如 RichTextBox 控件）能够保存文件。

通过

如何：使用 SaveFileDialog 组件保存文件

使用 SaveFileDialog 组件保存文件

另请参阅

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