从同一文本框中读取和写入文件

Question

I have a windows form that reads strings from a file and shows them all in a textbox when I press a button.

private void buttonTxt_Click(object sender, EventArgs e)
{
    string[] Test = File.ReadAllLines("C:\\testfile.txt");
    for (int i = 0; i < testfile.Length; i++)
    {
        TextBox.Text += testfile[i];
    }
}

I'd like to make two radio buttons. So that first button lets my program work the way I described (by default) AND second radio button makes it work vice versa -- so that I could write in a textbox myself and when I press a button it writes a new line to the same file . Is there a way to do it?

Answer 1

Simply add an if statement in this event handler and implement both sending and receiving the data. Done. Sample in principle:

private const string FilePath = @"C:\testfile.txt";

private void buttonTxt_Click(object sender, EventArgs e)
{
    if (radioReadMode.Checked) // check which radio button is selected
    {   // read mode
        string[] Test = File.ReadAllLines(FilePath);
        for (int i = 0; i < testfile.Length; i++)
            TextBox.Text += testfile[i];
    }
    else
    {   // write mode
        File.WriteAllText(FilePath, TextBox.Text);
    }
}

Answer 2

I believe this is what you might be looking for. If radio button 1 is checked then if the file exists it will read that file and put it into a textbox in the form. If you switch to radio button 2. You can type in the text box and then when you press the button it will append it to the file.

public partial class Form1 : Form
{
    System.IO.StreamReader sr;
    System.IO.StreamWriter sw;

    public Form1()
    {
        InitializeComponent();
        radioButton1.Checked = true;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (radioButton1.Checked == true)
        {
            if (System.IO.File.Exists("C:\\testfile.txt"))
            {

                try
                {
                    sr = new System.IO.StreamReader("C:\\testfile.txt");
                    while (!sr.EndOfStream)
                    {
                        textBox1.Text += sr.ReadLine() + "\r\n";
                    }
                }
                finally 
                {
                    sr.Close();
                    sr.Dispose();
                }
            }
        }

        if (radioButton2.Checked == true)
        {
            if (System.IO.File.Exists("C:\\testfile.txt"))
            {
                try
                {
                    sw = new System.IO.StreamWriter("C:\\testfile.txt", true);
                    string result = textBox1.Text;
                    string[] lststr = result.Split(new Char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);

                    foreach (string s in lststr)
                    {
                        sw.WriteLine(s);
                    }
                }
                finally 
                {
                    sw.Flush();
                    sw.Close();
                    sw.Dispose();
                }
            }
        }
    }

    private void radioButton1_CheckedChanged(object sender, EventArgs e)
    {
        textBox1.Clear();
        textBox1.ReadOnly = true;

    }

    private void radioButton2_CheckedChanged(object sender, EventArgs e)
    {
        textBox1.Clear();
        textBox1.ReadOnly = false;
    }


}

Answer 3

Yes, there's a way. Just add another button to your form and inside read the text from the text box this way:

var textBoxContent = TextBox.Text;

and save it to your file this way

File.WriteAllText("C:\\testfile.txt", textBoxContent);

Note: I recommend getting the path to your file into a variable