C# CHART APPLICATION

HI CAN ONE ONE HELP ME WITH THIS.I am trying to take Max and Min values from two Tetbox.text for Time...i;e my X-AXIS on C# chart is Time and i want to set the min and max time on runtime through textbox.text,,,code is here:

chart1.ChartAreas[0].AxisX.Minimum = DateTime.Parse(textBox7.Text).ToOADate(); chart1.ChartAreas[0].AxisX.Maximum = DateTime.Parse(textBox8.Text).ToOADate();