如何在C＃中单击按钮逐行读取文本文件

Question

I would like to read a text-file line by line. But, what I want to do is everytime the button is clicked it reads the next line and insert it into a textbox. So until the button is clicked it doesn't insert the next line into the text box.

[code]

    int lineCount = File.ReadAllLines(@"C:\test.txt").Length;
    int count = 0;


    private void button1_Click(object sender, EventArgs e)
    {
        var reader = File.OpenText(@"C:\test.txt");


        if (lineCount > count)
        {
            textBox1.Text = reader.ReadLine();
            count++;
        }
    }

// When I click the button more than once nothing happens with this code.

Answer 1

you should define the StreamReader as a field of your class:

System.IO.StreamReader file = null;
private void button1_Click(object sender, EventArgs e)
{
    string line;

    if (file == null)
        file = new System.IO.StreamReader("c:\\test.txt");
    if (!file.EndOfStream)
    {
        string line = file.ReadLine();
        textBox1.Text = line;
    }
    else
    {
        MessageBox.Show("End");
        file.Close();
    }
}