Admission GUI

Question

This is the same problem Admission but this time its a GUI

This is what I have done, I am just doing this way because I know how to do it, I will practice other ways after I find out what mistake I made.

So when I run it that's what I get

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.InvalidCastException: Unable to cast object of type 'System.Windows.Forms.TextBox' to type 'System.IConvertible'.
   at System.Convert.ToDouble(Object value)
   at Chapter4Exr4b.Form1.calculateButton_Click(Object sender, EventArgs e) in c:\users\alexander\documents\visual studio 2010\Projects\Chapter4Exr4b\Chapter4Exr4b\Form1.cs:line 27
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.239 (RTMGDR.030319-2300)
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll
----------------------------------------
Chapter4Exr4b
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///c:/users/alexander/documents/visual%20studio%202010/Projects/Chapter4Exr4b/Chapter4Exr4b/bin/Debug/Chapter4Exr4b.exe
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.235 built by: RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.1 built by: RTMRel
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.236 built by: RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.1 (RTMRel.030319-0100)
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.233 built by: RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.


****************************************************************************************************

            const double pointAverage = 3.0;
            const double testScore = 60;
            const double testScore1 = 80;

            double userInPut1, userInPut2;

            userInPut1 = Convert.ToDouble(inputTextBoxGpa);
            userInPut2 = Convert.ToDouble(inPutTextBoxTScore);

            if (userInPut1 >= pointAverage && userInPut2 >= testScore)
            {
                outputLabel.Text = " You are accepted, congratulations! ";
            }
            else if (userInPut1 < pointAverage && userInPut2 >= testScore1)
            {
                outputLabel.Text = " You are accepted, congratulations! ";
            }
            else
                outputLabel.Text = " Sorry ,but you do not meet the requirements, maybe other time? ";