C# - How to put extended WinForms Control on ToolBox

Question

I plan to add functionalities to TextBox with the following:

   public class TextBoxExt : TextBox  
    {
        protected override void OnKeyPress(KeyPressEventArgs e)
        {
            base.OnKeyPress(e);
        }

    }

The question is how can we use this TextBoxExt? Is there anyway to get this class onto the ToolBox so that we can just drag and drop it onto the form? If not, what is the best way to use the TextBoxExt?

Answer 1

1) Build you project with TextBoxExt, make sure it compiles ok.

2) With the form that you want TextBoxExt on, open the toolbox, right click and select "choose items"

3) Browse to you .exe or dll that you compiled in 1)

4) make sure that TextBoxExt has a tick next to it, press ok

5) TextBoxExt should appear in the toolbox, drag it onto your form

(There is another way of doing this, opening the designer file and renaming the instances of TextBox to TextBoxExt but manual editing of designer files can be considered hazardous by some)

Answer 2

Any custom control in your project should show up in the Toolbox automatically. I have found that sometimes the controls won't show until you close a re-open Visual Studio. I assume the issue has something to do with caching of the contents of the Toolbox.

Answer 3

You need to add a constructor to your derived class.

public class TextBoxExt : TextBox      
{        
    public TextBoxExt()
    {
    }

    protected override void OnKeyPress(KeyPressEventArgs e)        
    {            
         base.OnKeyPress(e);        
    }    
}

Answer 4

Your control should appear in the toolbox for your solution automatically. To have it appear for other projects, you have to do Choose Toolbox items, as others have said.

If you want to provide special design-time functionality, then you will also need to provide some additional designer related attributes and probably your own class derived from ControlDesigner.