>>Jeff,
>>
>>>I think I've successfully built the Jump Start for Windows Forms Application in C# (everything except this error handling works).
>>>
>>>In the final step (Testing the Customer Orders Form - C#) when I clear out the Customer ID field and press the save button I get the following:
>>>
>>>Object reference not set to an instance of an object.
>>> at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.SetErrorProvider(mmErrorProviderArgs arg)
>>> at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.DisplayErrorProviderRules(mmBusinessRuleBase bizRule)
>>> at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.DisplayBrokenRules(mmBusinessRule bizRule)
>>> at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.PostSaveProcessing(mmBusinessObject bizObj, String tableName, mmSaveDataResult result)
>>> at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.Save(mmBusinessObject bizObj, String tableName)
>>> at OakLeaf.MM.Main.Windows.Forms.mmButtonHelper.SaveHandler(Object button, String bindingSource, String bindingSourceMember, mmBaseBusinessObject& bizObj)
>>> at OakLeaf.MM.Main.Windows.Forms.mmButtonSave.mmButtonSave_Click(Object sender, EventArgs e)
>>
>>Looks like you're getting an error when trying to display a broken rule. I recommend setting a breakpoint in mmBusinessForm.SetErrorProvider() to see what is causing the error. Do you know which rule is being broken and why?
>>
>>Best Regards,
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>Kevin,
>
>I'm really new at this and I'm quite confused.
>
>To trace through mmBusinessForm.SetErrorProvider don't I need to add that project to my solution? I've done and I get the following error when I build:
>
>Error 1 Cryptographic failure while signing assembly 'C:\Program Files\Mere Mortals .NET Framework 2008\Mere Mortals Framework\obj\Debug\OakLeaf.MM2008.Framework.dll' -- 'Error reading key file 'c:\Program Files\Mere Mortals .NET Framework 2008\Mere Mortals Framework\keyPair.snk' -- The system cannot find the file specified. ' Mere Mortals Framework

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Ok, I reviewed your videos and found out how to exclude a project from the Build process. I can build, but I cannot edit mmBusinessForm.cs to put the breakpoint in because I get the following error:

The designer could not be shown for this file because none of the classes within it can be designed. The designer inspected the following classes in the file: mmBusinessForm --- The base class 'OakLeaf.MM.Main.Windows.Forms.mmEntityBusinessForm' could not be loaded. Ensure the assembly has been referenced and that all projects have been built.