Extend GridSort possibilities

[martinbu]

This PR extends missing GridSort overloads including an IComparer

1. GridSort ByDescending(Expression<Func<TGridItem, U>> expression, IComparer comparer)
2. GridSort ThenAscending(Expression<Func<TGridItem, U>> expression, IComparer comparer)
3. GridSort ThenDescending(Expression<Func<TGridItem, U>> expression, IComparer comparer)

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Additionally add methods to sort for a second column that is not affected by the sort direction

1. GridSort ThenAlwaysAscending(Expression<Func<TGridItem, U>> expression)
2. GridSort ThenAlwaysAscending(Expression<Func<TGridItem, U>> expression, IComparer comparer)
3. GridSort ThenAlwaysDescending(Expression<Func<TGridItem, U>> expression)
4. public GridSort ThenAlwaysDescending(Expression<Func<TGridItem, U>> expression, IComparer comparer)

[vnbaaij]

Hi Martin,

Can you explain why we would need this extensions? Is it for sorting on multiple columns? Because I dont' think the current rendering supports that.

[martinbu]

Hi Vincent,

I need it for the DataGrid SortBy of the TemplateColumn. I have added an example to the PR which demonstrates the use of at least one new extension: .ThenAlwaysAscending(...)

Sorting by multiple columns in DataGrid, at least as far as I can judge, works totally fine.

The other extensions can also be used in this context and should work as expected as demonstrated in the unit test cases.

What seems not yet supported is the use of SortBy in a PropertyColumn, although it is listed in the documentation of the PropertyColumn here:
https://www.fluentui-blazor.net/DataGrid --> PropertyColumn<TGridItem, TProp> Class --> Parameters --> SortBy

So I think the fact that it is listed here but not available can be interpreted as a "bug"?

[vnbaaij]

I think it is shown on PropertyColumn because it uses the same base class (ColumnBase) as TemplateColum

[martinbu]

I will check if SortBy can be enabled for PropertyColumn.