VB Migration Partner

KNOWLEDGE BASE - Forms and controls

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[PRB] A nonexisting property is generated for a control in the *.Designer.vb file

A VB6 control can generate any sort of property in the .frm file. We have tested all the properties of all the controls we support and ensured that no unrecognized property is ever generated in the code-behind portion of a VB.NET form, however it is possible that we missed a few of such properties.

As an example, one of our users reported that the DTPicker control can generate an entry labeled DateIsNull in the .frm file. (This entry appears if you both set the CheckBox property to True and the Value property to an empty string.) VB Migration Partner versions up to 1.00.03 translated this entry into a property in the VB.NET form, thus raising a compilation error because the VB6DTPicker control doesn’t expose a property with this name.

        ' (inside the generated VB.NET form)
        Me.DTPicker1.DateIsNull = -1

We have been able to fix the issue immediately after receiving the bug report. However, we are aware that problems of this sort can occur in the future and we want to illustrate a workaround that allows you to temporarily fix the problem until we release the next version.

In the specific case seen above, the user has been able to fix the problem by adding the following PostProcess pragma to the form at hand:

        '## PostProcess "\.DateIsNull\s+=\s+-1", ".Checked = False"

It is easy to adopt this technique to all similar cases.

However, please don’t forget to let us know about the issue, so that we can fix it at the soonest!

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