Question

我正在开展一个学校项目，但我无法弄清楚这最后一个错误。当第一个if语句返回false时，它应该打开一个saveFileDialog。但是不是继续进入else语句，而是直接抛出异常并且永远不会打开saveFile对话框。它给了我以下错误：Code: The path is not of a legal form.

我不明白问题所在。用户应该能够在弹出的保存对话框中选择路径。该文件尚不存在，它应该打开保存文件对话框来生成文件。

private void btnSave_Click(object sender, EventArgs e)
    {
        // Declare StreamWriter object
        StreamWriter outputFile;

        // Try to write file
        try
        {
            // If current file is > 0
            if (new FileInfo(currentFile).Length > 0)
            {
               // Create output file using current file
               outputFile = File.CreateText(currentFile);

                // Loop through current file and write lines to output file
                for (int i = 0; i < lstBoxLog.Items.Count; i++)
                {
                    outputFile.WriteLine(lstBoxLog.Items[i].ToString());
                }

                // Close text file
                outputFile.Close();
            }

            // Else open save dialog for user to save file
            else
            {
                // If save file dialog is equal to dialog result
                if (saveFile.ShowDialog() == DialogResult.OK)
                {
                    // Open output file object with create text
                    outputFile = File.CreateText(saveFile.FileName);

                    // Set currentFile to = savefile dialog
                    currentFile = saveFile.FileName;

                    // Loop through each line and write to file
                    for (int i = 0; i < lstBoxLog.Items.Count; i++)
                    {
                        outputFile.WriteLine(lstBoxLog.Items[i].ToString());
                    }

                    // Close text file
                    outputFile.Close();
                }

                // Else show error message
                else
                {
                    // Display message box dialog
                    MessageBox.Show("Cannot save file.", "Not Saved");
                } 
            }
        }

        // Display error message.
        catch (Exception ex)
        {
            // Display message box dialog
            MessageBox.Show("Save canceled. \n\nCode: " + ex.Message, "Save Error!");
        }
    }

Answer 1

try
{
  if (File.Exists(currentFile))
  {
    if (new FileInfo(currentFile).Length > 0)
    {
      ...
    }
  }
  else
  {
    //show save file dialog
  }

}
catch
{
  ...
}

Answer 2

根据罗布的建议，这就是我所使用的。

try
            {
                // If current file is > 0
                if (currentFile.Length > 0)
                {
                   // Create output file using current file
                   outputFile = File.CreateText(currentFile);

C＃Try / Catch跳过嵌套的If / Else语句并且不会打开SaveDialog

2 个答案: