如果文件已存在，则使用SaveFileDialog自动重命名该文件

Question

Chamal Fernando回答我的问题，非常感谢，

您可以在不使用文件流的情况下使用fileName。 将“保存文件对话框”的OverwritePrompt属性设置为false。 然后使while循环计算索引。

private void button1_Click（object sender，EventArgs e）         {             尝试             {                 // abre aopçãodesalvar como，para selecionar a pasta

            SaveFileDialog saveFileDialog1 = new SaveFileDialog
            {
                //InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.CommonPictures),

                Filter = "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif",
                Title = "Salvar o arquivo de imagem",
                RestoreDirectory = true,
            };

            saveFileDialog1.OverwritePrompt = false;
            saveFileDialog1.ShowDialog();

            // se o nome do arquivo não for vazio, abre para salvar
            if (saveFileDialog1.FileName != "")
            {
                int fileCount = 0;
                string fullPath = saveFileDialog1.FileName;
                string fileNamewithoutExt = Path.GetFileNameWithoutExtension(fullPath);
                string dirPath = Path.GetDirectoryName(fullPath);
                string ext = Path.GetExtension(fullPath);
                string newPath = string.Empty;

                while (File.Exists(newPath = Path.Combine(dirPath, fileNamewithoutExt + (fileCount > 0 ? "[" + fileCount + "]" : "") + ext)))
                { fileCount++; }

                // Salva a imagem no formato certo
                switch (saveFileDialog1.FilterIndex)
                {
                    case 1:
                        this.pictureBoxScreenshot.Image.Save(newPath,
                           System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;

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

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

        }
        catch (Exception ex)
        { }
    }