清除richtextbox并覆盖上一个条目

Question

I have a richtextbox that will overwrite a file that has already been saved before.

If I need to start a new file and then save it as a new file, it just overwrites the first file that was saved.

How can this be done?

String fileLocation;
    private void SaveMyFile_Click(object sender, EventArgs e)
    {
        var performSave = true;
        if (String.IsNullOrEmpty(fileLocation))
        {
            performSave = SetFileLocation();
        }
        if (performSave)
            richTextBox1.SaveFile(fileLocation, RichTextBoxStreamType.PlainText);

    }

    private bool SetFileLocation()
    {
        SaveFileDialog saveFile1 = new SaveFileDialog();
        saveFile1.DefaultExt = "*.txt";
        saveFile1.Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*|RTF Files|*.rtf";
        if (saveFile1.ShowDialog() == System.Windows.Forms.DialogResult.OK &&
        saveFile1.FileName.Length > 0)
        {
            fileLocation = saveFile1.FileName;
            return true;
        }
        return false;
    }

Answer 1

第一次保存后的FileLocation变量（SetLocation）不为null或为空，这就是为什么当您再次保存（单击SaveMyFile按钮）时，它不会输入SetFileLocation方法，而只是执行SaveFile

Answer 2

When you "start a new file", just set fileLocation to null and you should get the SaveFileDialog to show up again to allow you to enter a new file location. The code below is the crucial bit:

if (String.IsNullOrEmpty(fileLocation))
{
   performSave = SetFileLocation();
}

The SetFileLocation() method won't be called unless fileLocation is null or the empty string.