[c#] Reading a text file using OpenFileDialog in windows forms

Here's one way:

Stream myStream = null;
OpenFileDialog theDialog = new OpenFileDialog();
theDialog.Title = "Open Text File";
theDialog.Filter = "TXT files|*.txt";
theDialog.InitialDirectory = @"C:\";
if (theDialog.ShowDialog() == DialogResult.OK)
{
    try
    {
        if ((myStream = theDialog.OpenFile()) != null)
        {
            using (myStream)
            {
                // Insert code to read the stream here.
            }
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
    }
}

Modified from here:MSDN OpenFileDialog.OpenFile

EDIT Here's another way more suited to your needs:

private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
    OpenFileDialog theDialog = new OpenFileDialog();
    theDialog.Title = "Open Text File";
    theDialog.Filter = "TXT files|*.txt";
    theDialog.InitialDirectory = @"C:\";
    if (theDialog.ShowDialog() == DialogResult.OK)
    {
        string filename = theDialog.FileName;

        string[] filelines = File.ReadAllLines(filename);

        List<Employee> employeeList = new List<Employee>();
        int linesPerEmployee = 4;
        int currEmployeeLine = 0;
        //parse line by line into instance of employee class
        Employee employee = new Employee();
        for (int a = 0; a < filelines.Length; a++)
        {

            //check if to move to next employee
            if (a != 0 && a % linesPerEmployee == 0)
            {
                employeeList.Add(employee);
                employee = new Employee();
                currEmployeeLine = 1;
            }

            else
            {
                currEmployeeLine++;
            }
            switch (currEmployeeLine)
            {
                case 1:
                    employee.EmployeeNum = Convert.ToInt32(filelines[a].Trim());
                    break;
                case 2:
                    employee.Name = filelines[a].Trim();
                    break;
                case 3:
                    employee.Address = filelines[a].Trim();
                    break;
                case 4:
                    string[] splitLines = filelines[a].Split(' ');

                    employee.Wage = Convert.ToDouble(splitLines[0].Trim());
                    employee.Hours = Convert.ToDouble(splitLines[1].Trim());
                    break;


            }

        }
        //Test to see if it works
        foreach (Employee emp in employeeList)
        {
            MessageBox.Show(emp.EmployeeNum + Environment.NewLine +
                emp.Name + Environment.NewLine +
                emp.Address + Environment.NewLine +
                emp.Wage + Environment.NewLine +
                emp.Hours + Environment.NewLine);
        }
    }
}