feat: add ability to set tooltip for column header to FluentDataGrid

[Leon99]

🙋 Feature Request

I'd like to set a tooltip for a column header that is different from Title, but it seems impossible at the moment.

💁 Possible Solution

I tried to override HeaderCellItemTemplate, but generated code misses a necessary attribute:

That autogenerated attribute that applies the necessary styling is missing when setting HeaderCellItemTemplate as

<div class="col-title">
   <div class="col-title-text" title="@tooltip">@Title</div>
</div>

[vnbaaij]

In determining what tooltip to show in the header, the following code is now used:

string? tooltip = Tooltip ? Title : null;

(in ColumnBase.razor, right above where your <div... code comes from.

What if we change that to:

string? tooltip = Tooltip ? (TooltipText ?? Title) : null;

That way you could use the TooltipText parameter to change the tooltip text even with the standard header template.

ps: In your HeaderCellItemTemplate, I think you should be able to get that attribute added by using ::deep in your own styles

[vnbaaij]

Turns out we can't do it in the way I suggested. When rendering the headers, we do not have an actual item available yet that can act as the context for getting the TooltipText function executed,

[vnbaaij]

Creating a new PR for this. We have now solved this by adding a new HeaderTooltip parameter to the column:

<TemplateColumn Tooltip="true" HeaderTooltip="Flag of each team" TooltipText="@(c => "Flag of " + c.Name)" Title="Rank"...