I cant write to text file

Question

Hello everyone,
My all codes are below. This codes are creating "mac.txt" file but I cant write any data in this file. I dont know what is the problem?


using System.Text;
using System.Windows.Forms;
using System.IO;

     private void button1_Click(object sender, EventArgs e)
        {
            StreamWriter dosya = new StreamWriter("mac.txt");
            dosya.WriteLine("1231231231");
            dosya.Write("123123123");
        }