Conversion from textbox to chart representation

Question

I am receiving from a sensor over the serial conection in a textbox a series of chars. For example: "@;.1AB@@)" and i want to represent their values in a chart in VS. The decimals are OK, but not the rest. I was trying to convert like this:

tboxReceive.Invoke((MethodInvoker)(() => tboxReceive.Text += getvalue)); chart1.Invoke((MethodInvoker)(() => chart1.Series["temp"].Points.AddXY(DateTime.Now.ToLongTimeString(), Convert.ToInt32(getvalue))));

but is not working! Some guides?

Thanks in advance!

to convert the string "@;.1AB@@)" in a separate value for each char