When I try to set 'RefTextBox.Value = value' I get a warning:
How is the Value of a TextBox supposed to be set programmatically without binding it to a variable?
You can "set" in the Razor markup without binding it.
If your value (MyValue) is acquired after the first render, issue StateHasChanged after it is acquired.
Binds the value (two-way):
Only sets the value (one-way):
The 2nd example I gave is not binding it; it is the functional equivalent of what you are trying to do, but it will not give you the warning.
BL0005 is a warning, not an error. Manipulating razor components in the code behind is discouraged, but if you are aware of the downfalls, go ahead. I didn't even bother to investigate what the downfalls were, because I knew that I could it the way that made the warning disappear. I can't think of any functional difference between the two methods, so make your own choices.