在记事本程序在C＃中“保存文件”的正常运作(Proper functioning of 'S

public partial class Form1 : Form
{
    SaveFileDialog sfd = new SaveFileDialog();
    OpenFileDialog ofd = new OpenFileDialog();
    public string contents = string.Empty;
    public Form1()
    {
        InitializeComponent();
        this.Text = "Untitled";
    }

    private void newToolStripMenuItem_Click(object sender, EventArgs e)
    {
        if (richTextBox1.Text != contents)
        {
            DialogResult dr = MessageBox.Show("Do You want to save the changes made to " + this.Text, "Save", MessageBoxButtons.YesNoCancel);
            if (dr == DialogResult.Yes)
            {
                sfd.Title = "Save";
                if (SaveFile() == 0)
                    return;
                else
                {
                    richTextBox1.Text = "";
                    this.Text = "Untitled";
                }
                contents = "";
            }
            else if (dr == DialogResult.No)
            {
                richTextBox1.Text = "";
                this.Text = "Untitled";
                contents = "";
            }
            else
            {
                richTextBox1.Focus();
            }
        }
        else
        {
            this.Text = "Untitled";
            richTextBox1.Text = "";
            contents = "";
        }

    }
    private int SaveFile()
    {
        sfd.Filter = "Text Documents|*.txt";
        sfd.DefaultExt = "txt";
        if (sfd.ShowDialog() == DialogResult.Cancel)
        {
            richTextBox1.Focus();
            return 0;
        }
        else
        {
            contents = richTextBox1.Text;
            if (this.Text == "Untitled")
                richTextBox1.SaveFile(sfd.FileName,RichTextBoxStreamType.PlainText);
            else
            {
                sfd.FileName = this.Text;
                richTextBox1.SaveFile(sfd.FileName,RichTextBoxStreamType.PlainText);
            }
            this.Text = sfd.FileName;
            return 1;
        }


    }
    private void OpenFile()
    {
        ofd.Filter = "Text Documents|*.txt";
        if (ofd.ShowDialog() == DialogResult.Cancel)
            richTextBox1.Focus();
        else
        {
            richTextBox1.LoadFile(ofd.FileName, RichTextBoxStreamType.PlainText);
            this.Text = ofd.FileName;
            contents = richTextBox1.Text;
        }
    }

    private void openToolStripMenuItem_Click(object sender, EventArgs e)
    {
        if (richTextBox1.Text != contents)
        {
            DialogResult dr = MessageBox.Show("Do You want to save the changes made to " + this.Text, "Save", MessageBoxButtons.YesNoCancel);
            if (dr == DialogResult.Yes)
            {
                SaveFile();
                OpenFile();
            }
            else if (dr == DialogResult.No)
            {
                OpenFile();
            }
            else
            {
                richTextBox1.Focus();
            }
        }
        else
            OpenFile();
    }

    private void saveToolStripMenuItem_Click(object sender, EventArgs e)
    {
        SaveFile();
    }

    private void saveAsToolStripMenuItem_Click(object sender, EventArgs e)
    {
        sfd.Filter = "Text Documents|*.txt";
        sfd.DefaultExt = "txt";
        if (sfd.ShowDialog() == DialogResult.Cancel)
        {
            richTextBox1.Focus();
        }
        else
        {
            contents = richTextBox1.Text;
            richTextBox1.SaveFile(sfd.FileName, RichTextBoxStreamType.PlainText);

            this.Text = sfd.FileName;
        }            
    }

当我们打开Windows的记事本应用程序，然后打开一个文件，改变它的内容，并保存它，它只是被保存，而无需打开保存文件对话框。但是，在记事本程序，我创建上面保存文件对话框上单击“保存”保存更改文件的内容后，将打开。尽管相同的文件名出现在保存文件对话框，但是，点击“保存”，它提供了消息“相同的文件名已经存在。是否要取代它？”。这就是我想删除并作出改变的内容直接保存到打开的文件，而无需打开保存文件对话框的内容。

Answer 1:

设置sfd.OverwritePrompt =虚假的建设时间后的ShowDialog之前抑制覆盖警告。

Answer 2:

你想有两个选择保存：A“另存为...”按钮和“保存”按钮。您可以创建一个string来保存打开的文件的路径。如果用户指定一个新的位置，当他们保存文件的位置也可以改变。如果用户没有打开该文件时，“另存为...”按钮，将打开定期保存文件对话框。一旦用户指定的文档的位置，你可以将文件路径保存到字符串，并使用'的StreamWriter”将其保存，而不对话框：

...
using System.IO;
...

public partial class Form1 : Form
{
    SaveFileDialog sfd = new SaveFileDialog();
    OpenFileDialog ofd = new OpenFileDialog();
    public string contents = string.Empty;

    //string to hold file location
    string currentFileLoc;


    public Form1()
    {
        InitializeComponent();
        this.Text = "Untitled";
    }

    private void newToolStripMenuItem_Click(object sender, EventArgs e)
    {
        if (richTextBox1.Text != contents)
        {
            DialogResult dr = MessageBox.Show("Do You want to save the changes made to " + this.Text, "Save", MessageBoxButtons.YesNoCancel);
            if (dr == DialogResult.Yes)
            {
                sfd.Title = "Save";
                if (SaveFile() == 0)
                    return;
                else
                {
                    richTextBox1.Text = "";
                    this.Text = "Untitled";
                }
                contents = "";
            }
            else if (dr == DialogResult.No)
            {
                richTextBox1.Text = "";
                this.Text = "Untitled";
                contents = "";
            }
            else
            {
                richTextBox1.Focus();
            }
        }
        else
        {
            this.Text = "Untitled";
            richTextBox1.Text = "";
            contents = "";
        }

    }
    private int SaveFile()
    {
        sfd.Filter = "Text Documents|*.txt";
        sfd.DefaultExt = "txt";
        if (sfd.ShowDialog() == DialogResult.Cancel)
        {
            richTextBox1.Focus();
            return 0;
        }
        else
        {
            contents = richTextBox1.Text;
            if (this.Text == "Untitled")
                richTextBox1.SaveFile(sfd.FileName,RichTextBoxStreamType.PlainText);
            else
            {
                sfd.FileName = this.Text;
                richTextBox1.SaveFile(sfd.FileName,RichTextBoxStreamType.PlainText);
            }
            this.Text = sfd.FileName;
            //
            currentFileLoc = sfd.FileName;
            return 1;
        }


    }
    private void OpenFile()
    {
        ofd.Filter = "Text Documents|*.txt";
        if (ofd.ShowDialog() == DialogResult.Cancel)
            richTextBox1.Focus();
        else
        {
            richTextBox1.LoadFile(ofd.FileName, RichTextBoxStreamType.PlainText);
            this.Text = ofd.FileName;
            contents = richTextBox1.Text;
        }

        currentFileLoc = ofd.FileName;
        this.Text = currentFileLoc;
    }

    private void openToolStripMenuItem_Click(object sender, EventArgs e)
    {
        if (richTextBox1.Text != contents)
        {
            DialogResult dr = MessageBox.Show("Do You want to save the changes made to " + this.Text, "Save", MessageBoxButtons.YesNoCancel);
            if (dr == DialogResult.Yes)
            {
                SaveFile();
                OpenFile();
            }
            else if (dr == DialogResult.No)
            {
                OpenFile();
            }
            else
            {
                richTextBox1.Focus();
            }
        }
        else
            OpenFile();
    }

    private void saveToolStripMenuItem_Click(object sender, EventArgs e)
    {
        Save();
    }

    private void saveAsToolStripMenuItem_Click(object sender, EventArgs e)
    {
        SaveFile();            
    }

    //new method
    private void Save()
    {
        if (currentFileLoc != null)
        {
            using (StreamWriter writer = new StreamWriter(currentFileLoc))
            {
                writer.WriteLine(richTextBox1.Text);
            }
        }

        else
          saveFile();
     }
 }

我建议你也封闭using(...){ }块中try/catch语句，并处理任何异常。