Blazor inline editing table and getting all component values on event

You're setting the input values using the object values but not binding them.

<input type="text" class="form-control" placeholder="Give the instance a name" value="@instance.DisplayName" />

This will set the value of the input control but won't pass updates to anything.

You need to @bind the values to the property, e.g.

<input type="text" class="form-control" placeholder="Give the instance a name" @bind="@instance.DisplayName" />

This will update the underlying object's properties with any changes.

More: https://docs.microsoft.com/en-us/aspnet/core/blazor/data-binding?view=aspnetcore-3.1