SerialPort.Read method hanging

Question

Have built a simple SerialPort client and server to test writing to and reading from COM ports. The problem is that when I attempt to read, it hangs. I know that the serial port communication itself is working fine, because I transmit from a terminal server and receive data back on a hyperterminal client app no problem. Here is the code for my server:

public partial class Form1 : Form
{
    SerialPort Port = new SerialPort("COM5", 9600, Parity.None, 8, StopBits.One);

    public Form1()
    {
        InitializeComponent();
    }

    private void btnSendText_Click(object sender, EventArgs e)
    {
        Port.Open();
        Port.Write(txtSendText.Text + "!%");
        Port.Close();
    }
}

Here is the code for my client:

    private System.IO.Ports.SerialPort port = new System.IO.Ports.SerialPort("COM4", 9600, Parity.None, 8, StopBits.One);
    public Form1()
    {
        InitializeComponent();
        this.port.DataReceived += new System.IO.Ports.SerialDataReceivedEventHandler(this.port_DataReceived);
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        CheckForIllegalCrossThreadCalls = false;
        if (port.IsOpen == false)
            port.Open();
    }

    private void port_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
    {
        textBox1.Text = (port.ReadTo("!%"));
        if (port.ReadExisting().Length == 0)
        {
            listBox1.Items.Add(textBox1.Text);
            textBox1.Text = "";
        }
    }

Have been troubleshooting this over and over in a debugger with all kinds of different type of SerialPort read overloads, but it still hangs on port.ReadTo(...). Does anyone have any suggestions? TIA.

Answer 1

Thank you to everyone who posted. It turns out that I was using SharpDevelop_4.4.1.9729 to build and debug the application. When I read this post, I became suspicious of the open source IDE debugger,

http://social.msdn.microsoft.com/Forums/vstudio/en-US/ed9605b6-3c97-4b53-949a-f56f9da58306/serialport-hang?forum=netfxbcl

So I tried it again instead, this time using Microsoft Visual Studio 2010 Professional, and it worked with no problem!

UPDATE:

Also, if I choose the option to "Run without debugger" in Sharp Develop, it also works without hanging, so it definitely is a problem with the Sharp Develop debugger.