C#轉換圖片檔案格式

將圖片轉換為另一種格式的映像時，需要使用ImageFormat類，該類主要用來指定映像的格式。代碼如下：

private void button2_Click(object sender, EventArgs e)
{
    //轉換影像檔
    if (MyBitmap == null)
    {
        MessageBox.Show("請首先選擇一幅映像！", "資訊提示");
        return;
    }
    SaveFileDialog saveDlg = new SaveFileDialog();
    if (saveDlg.ShowDialog() == DialogResult.Cancel)
        return;
    string fileName = saveDlg.FileName;
    try
    {
        if (this.comboBox1 .SelectedIndex ==0)
        {
            MyBitmap.Save(fileName + ".bmp", System.Drawing.Imaging.ImageFormat.Bmp);
        }
        if (this.comboBox1.SelectedIndex ==1)
        {
            MyBitmap.Save(fileName + ".jpg", System.Drawing.Imaging.ImageFormat.Gif);
        }
        if (this.comboBox1.SelectedIndex == 2)
        {
            MyBitmap.Save(fileName + ".png", System.Drawing.Imaging.ImageFormat.Jpeg);
        }
        if (this.comboBox1.SelectedIndex == 3)
        {
           MyBitmap.Save(fileName + ".gif", System.Drawing.Imaging.ImageFormat.Png);
        }
        if (this.comboBox1.SelectedIndex == 4)
        {
            MyBitmap.Save(fileName + ".tif", System.Drawing.Imaging.ImageFormat.Tiff);
        }
        if (this.comboBox1.SelectedIndex == 5)
        {
            MyBitmap.Save(fileName + ".wmf", System.Drawing.Imaging.ImageFormat.Wmf);
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "資訊提示");
    }
}