Using CWNumEdit Control from Measurement Studio with VS .Net 2003

[mtd32610]

I have a bunch of CWNumEdit controls that I want to populate from data within a file.  But when I go to execute these lines of code I get an error message of

An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll

Additional information: Property is read-only

I am not sure how to get around this error since I thought I should be able to populate the control from normal user input.  If someone knows away to properly populate the control please let me know.

Thanks.

[Jervin Justin]

Hi mtd32610,

How are you trying to populate the CWNumEdit control? What is the line that gives you the error message?

The normal way to populate the control is to use:

<control>.Value = <numeric_value>;

You can see an example of doing this in the Measurement Studio shipping example for Visual C++ located at:
C:\Documents and Settings\All Users\Documents\National Instruments\MStudioVS2003\VCNET\Examples\UI\NumEdit\Simple Numeric

[mtd32610]

Jervin,
    The following line is what is causing the problem
        axCWNE_TOTAL->set_Text(Convert::ToString(m_pMyStruct->uTotal));

    The application is a WinForm developed in VS .Net 2003 with C++ and for some reason the numerical edit boxes won't work right.  The program just seems to stop executing there for some reason.  I thought I should be able to populate it with no problem.

[MartyMcDAX]

What type of object does the axCWNE_TOTAL pointer reference?  I believe you are calling the set_Text method on the wrong object.  Furthermore, as mentioned earlier in this post and on this forum, you do not need to call the set_Text method at all to update the value of a CWNumEdit control.  You simply need to set the "Value" property for the variable associated with your control.  This variable should be of type CNiNumEdit.

Follow these steps to create a CWNumEdit control that you can update:
1. Drag a CWNumEdit control onto the dialog from the Measurement Studio palette.
2. "Add a Variable" for this control and name it appropriately.
3. In your code, call
<control name>.Value = <new value>;
to update the value of your numeric edit control.  The expected type of <new value> is a double, not a string.

I hope that helps!

Message Edited by Marty_H on 06-12-2008 09:57 AM

[mtd32610]

The application is a Winform and so when I drag the control to the window, a control variable is create automatically for you.
The variable is  AxInterop::CWUIControlsLib::AxCWNumEdit *  axCWNE_TOTAL.  I access the set functions for other controls and it does cause any issues, only the numerical edit controls.

[MartyMcDAX]

Thanks for the update.  Even though you are using a WinForm, you are still going to set the 'Value' property for this object.  You will probably need to put your integer/double value inside the __box() method.  This will create a managed object on the heap that can be used to update your control.  So your statement to update the control should look something like this:

axCWNE_TOTAL->Value = __box( <numeric value> ) ;