Dear All, I get an error as follows. The codes of the application are shown below the screen capture. Error * Call stack * Code of ypanel * Solution Explorer *

I think that the parent is not yet available because the control was not added yet to a form or control. Try executing the code inside the Load or ParentChanged event handlers.

When writing your code to read the value of .Parent , you should consider that null is a valid input, as documented by Microsoft in places such as https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.parent?view=windowsdesktop-7.0#remarks Setting .Parent to null explicitly has its meaning. And if you don't like that, you should assign whatever you like to .Parent when creating such UI controls.

System.Windows.Forms.Control.Parent.get returned null

BenTam 1,761

Dear All,

I get an error as follows. The codes of the application are shown below the screen capture.

Error *

Call stack *

Code of ypanel *

Solution Explorer *

2 answers

Viorel 119K Reputation points

2022-10-17T14:06:24.27+00:00

I think that the parent is not yet available because the control was not added yet to a form or control.

Try executing the code inside the Load or ParentChanged event handlers.
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BenTam 1,761 Reputation points

2022-10-18T14:45:45.64+00:00

Hi @Viorel

Thanks for your reply. Do you mean putting the properties on the containing form? Could you write the sample code for me?

Viorel 119K Reputation points

2022-10-19T07:22:40.493+00:00

Open your Panel user control in Form Designer and add the handler for Load event. Then move the problematic code (that creates the Lib object) to this handler.

When the user controls will be used in some of your form, the Parent will not be null.

BenTam 1,761 Reputation points

2022-10-20T15:00:27.707+00:00

Hi @Viorel

Thanks for your reply. I will try it later.
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Lex Li (Microsoft) 5,837 Reputation points Microsoft Employee

2022-10-19T05:49:26.657+00:00

When writing your code to read the value of .Parent, you should consider that null is a valid input, as documented by Microsoft in places such as

https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.parent?view=windowsdesktop-7.0#remarks

Setting .Parent to null explicitly has its meaning. And if you don't like that, you should assign whatever you like to .Parent when creating such UI controls.
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System.Windows.Forms.Control.Parent.get returned null

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