CODEWITHSUNDEEP
c#winformsinheritance
Ivan-Mark Debono
Ivan-Mark Debono

Reputation: 16310

How to return base form from derived form?

I have a form FormA that inherits from Form. I override OnLoad as follows:

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);

    //Do FormA stuff here            
}

Now I derive a second form FormB from FormA so that I have the same form layout. However I want to also override OnLoad but if I do this:

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);

    //Do FormB stuff here        
    //without doing FormA stuff    
}

It would call FormA's OnLoad which I do not want.

In this scenario, how can I call the Form Onload event from within FormB?

Upvotes: 0

Views: 153

Answers (2)

Tanveer Badar
Tanveer Badar

Reputation: 5523

You can remove the call to base.OnLoad(e). However, I strongly advice against that if there's any sort of processing which manipulates the controls, like databinding them.

Visual inheritance does not find much use, you are better off refactoring common functionality into a user control and add that to both forms instead of inheriting one from the other.

Upvotes: 0

Patrick Hofman
Patrick Hofman

Reputation: 156978

You can't with this code. You can't say base.base.OnLoad for example.

I guess you want to do something like this.

FormA:

protected sealed override void OnLoad(EventArgs e)
{
    base.OnLoad(e);

    MyOnLoad(e);
}

protected virtual void MyOnLoad(EventArgs e)
{
    // FormA onload
}

FormB:

protected override void MyOnLoad(EventArgs e)
{
    // FormB onload
}

Here you force to always call Form.OnLoad, but you can change the OnLoad behavior per derived class in MyOnLoad.

Upvotes: 1

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