小编sha*_*han的帖子

我需要让我的代码读取文件是否存在创建else附加.现在它正在读取它是否确实存在创建和追加.这是代码:

if (File.Exists(path))
{
    using (StreamWriter sw = File.CreateText(path))
    {

我会这样做吗？

if (! File.Exists(path))
{
    using (StreamWriter sw = File.CreateText(path))
    {

编辑:

string path = txtFilePath.Text;

if (!File.Exists(path))
{
    using (StreamWriter sw = File.CreateText(path))
    {
        foreach (var line in employeeList.Items)
        {
            sw.WriteLine(((Employee)line).FirstName);
            sw.WriteLine(((Employee)line).LastName);
            sw.WriteLine(((Employee)line).JobTitle);
        }
    }
}
else
{
    StreamWriter sw = File.AppendText(path);

    foreach (var line in employeeList.Items)
    {
        sw.WriteLine(((Employee)line).FirstName);
        sw.WriteLine(((Employee)line).LastName);
        sw.WriteLine(((Employee)line).JobTitle);
    }
    sw.Close();
}

}

我问,因为我正在为学校做项目.是的,这是功课.但是,我试图更多地了解它.

这是被问到的一个例子.

•当用户单击"保存"按钮时,将所选记录写入txtFilePath中指定的文件(绝对路径不相对),而不截断当前内部的值.

这就是我的意思,

private void button2_Click(object sender, EventArgs e)
{
    if (saveFileDialog1.ShowDialog() == DialogResult.OK)
    {
        StreamWriter myWriter = new StreamWriter(saveFileDialog1.FileName);
        myWriter.Write(txtFilePath.Text);
        myWriter.Close();
    }
}

现在,我不明白我是否做得对.我知道当我将它保存到我的桌面并从列表框中删除它时,当我再次尝试重新加载时,没有任何显示.这就是我的表格,

private void button1_Click(object sender, EventArgs e)
{
    if (openFileDialog1.ShowDialog() == DialogResult.OK)
    {
        StreamReader myReader = new StreamReader(openFileDialog1.FileName);
        txtFilePath.Text = openFileDialog1.FileName;
        txtFilePath.Text = myReader.ReadToEnd();
        myReader.Close();
    }
}    

这是负载,

private void Form1_Load(object sender, EventArgs e)
{
    string[] myFiles = Directory.GetFiles("C:\\");
    foreach (string filename in myFiles)
    {
        FileInfo file = new FileInfo(filename);
        employeeList.Items.Add(file.Name);
    }

    //...

有人可以帮我理解这个吗？