Question

出于某种原因，我遇到了SaveFileDialog的问题。我想要做的就是逐行从文本框中提取数据并将其写入文本文件，然后将该文本文件保存到桌面。第一段代码工作正常（虽然它不保存到桌面）。代码的第二位是我想要使用的，但是当它创建文本文件时，文本文件是空的。我在第二段代码中做错了什么？

此代码有效，但它不会保存到桌面，并且不如第二个代码那么好。

//When the Save button is clicked the contents of the text box will be written to a text file.
private void saveButton_Click(object sender, EventArgs e)
{
    int textBoxLines = textBox.Lines.Count();
    if (File.Exists(saveFile))
    {
        result = MessageBox.Show("The file " + saveFile + " already exists.\r\nDo you want to replace it?", "File Already Exists!", MessageBoxButtons.YesNo);

        if (result == DialogResult.Yes)
        {
            TextWriter tw1 = new StreamWriter(saveFile);
            for (int i = 0; i < textBoxLines; i++)
            {
                tw1.WriteLine(textBox.Lines.GetValue(i));
            }

            tw1.Close();

        }

        if (result == DialogResult.No)
        {
            MessageBox.Show("Please move or rename existing " + saveFile + "\r\nBefore attempting to save again.", "Message");
        }
    }

    else
    {
        TextWriter tw2 = new StreamWriter(saveFile);
        for (int i = 0; i < textBoxLines; i++)
        {
            tw2.WriteLine(textBox.Lines.GetValue(i));
        }

        tw2.Close();

    }

}

此代码不起作用，但这是我想要使用的。

//When the Save button is clicked the contents of the text box will be written to a text file.
private void saveButton_Click(object sender, EventArgs e)
{
    int textBoxLines = textBox.Lines.Count();

    Stream saveStream;
    SaveFileDialog saveDialog = new SaveFileDialog();
    saveDialog.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
    saveDialog.FilterIndex = 2;
    saveDialog.RestoreDirectory = true;
    saveDialog.FileName = (saveFile);
    saveDialog.InitialDirectory = (Environment.GetFolderPath(Environment.SpecialFolder.Desktop));

    if (saveDialog.ShowDialog() == DialogResult.OK)
    {
        if ((saveStream = saveDialog.OpenFile()) != null)
        {
            StreamWriter tw = new StreamWriter(saveStream);
            for (int i = 0; i < textBoxLines; i++)
            {
                tw.WriteLine(textBox.Lines.GetValue(i));
            }

            saveStream.Close();
        }
    }
}

Answer 1

写完内容后，您还没有tw.Close()。缓冲区不会被刷新。

Answer 2

正如ChrisT所说，你永远不会关闭StreamWriter。但是，作为最佳实践，您应该有using块来关闭/处理这些块。

//When the Save button is clicked the contents of the text box will be written to a text file.
private void saveButton_Click(object sender, EventArgs e)
{
    int textBoxLines = textBox.Lines.Count();

    SaveFileDialog saveDialog = new SaveFileDialog();
    saveDialog.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
    saveDialog.FilterIndex = 2;
    saveDialog.RestoreDirectory = true;
    saveDialog.FileName = (saveFile);
    saveDialog.InitialDirectory = (Environment.GetFolderPath(Environment.SpecialFolder.Desktop));

    if (saveDialog.ShowDialog() == DialogResult.OK)
    {
        using (Stream savestream = saveFialog.OpenFile())
        {

            if (saveStream != null)
            {
                using(StreamWriter tw = new StreamWriter(saveStream))
                {

                    for (int i = 0; i < textBoxLines; i++)
                    {
                        tw.WriteLine(textBox.Lines.GetValue(i));
                    }
                }
            }
        }
    }
}

SaveFileDialog问题（C＃）（VS2008）

2 个答案: