Add support for footers to ListViewGroup

[hughbe]

• You can set the LVGF_FOOTER flag on mask and set pszFooter to a valid string and cchFooter to the length of the string
• You can set the LVGF_ALIGN flag on mask and set the uAlign to a valid LVGA_FOOTER_CENTER value

Proposed API

This would add the following APIs to ListViewGroup:

public class ListViewGroup
{
    ...
    public string Footer { get; set; }
    public HorizontalAlignment FooterAlignment { get; set; }
    ...
}

Example

var group = new ListViewGroup
{
     Footer = "NewFooter",
     FooterAlignment = HorizontalAlign.Center
};

[RussKie]

The team had some preliminary discussions about enhancing the control.
Could you spare few minutes and provide answers to the following questions so we can take it to the next level:

• Will VS Designer need to support the feature? If yes, describe how you expect it to funсtion.
• What impact will it have on accessibility?
• Will this feature need to be localized or be localizable?

[hughbe]

Will VS Designer need to support the feature? If yes, describe how you expect it to function.

Yes. I would expect "Footer" and "FooterAlignment" to appear in the following editor (same as "Header" and "HeaderAlignment"

What impact will it have on accessibility?

I don't think ListViewGroups header is currently accessible at all? So I'm not really sure what we actually expect from accessibility here

Will this feature need to be localized or be localizable?

I would expect the user to need to localise the footer string, but I think (?) this is the responsibility of the user. Any documentation will need to be localized.

[weltkante]

I would expect "Footer" and "FooterAlignment" to appear in the following editor (same as "Header" and "HeaderAlignment"

I would expect the user to need to localise the footer string

Probably both will just work by itself if the new properties are annotated correctly with metadata attributes. Since there is precedence with existing Header and HeaderAlignment the new properties would basically want the same treatment as the existing properties.

If VS feels the need to do anything special about the existing properties it would have to do the same for the new properties (ideally it shouldn't need to but you never know if VS designer puts an override onto a TypeDescriptor to implement some workaround or customized experience, like it does for example on Image properties where it overrides the default TypeDescriptor to provide a different selection dialog than someone would get outside VS, you can only know if you have access to the VS designer source).

[hughbe]

In terms of accessibility, see #1726

[terrajobst]

Video

• Looks good as proposed

namespace System.Windows.Forms
{
    public partial class ListViewGroup
    {
        public string Footer { get; set; }
        public HorizontalAlignment FooterAlignment { get; set; }
    }
}