[DatePicker] Allow for value and valueLink props

[stefanmayer13]

If the defaultDate props change on the DatePicker, the value on the input field stays the same. I already created a PR to fix that issue.

[stefanmayer13]

I realized that defaultDate prop might not be the best way to change the date from the outside, as it might override a user chosen date. I can't really think of a meaningful usecase where the defaultDate prop might change from the outside and you don't want it to override the inside value, but it might still be confusing. Any suggestions about another way to change the displayed value from the outside?

[hai-cea]

@stefanmayer13 Have you tried setting the value prop? Also, you could try to use setDate as well.

[stefanmayer13]

Setting the value has multiple issues:

• It is not using formatDate (ugly workaround would be to already use the formatDate function outside)
• It only sets the value of the input field. The date picker date stays the same.
• It causes the following error after setting a value with the date picker Cannot call TextField.setValue when value or valueLink is defined as a property., because the input field is now controlled.

Using setDate is not really an option if i want to use JSX and props.

[JAStanton]

I think this should be closed since mui/material-ui#1170 was just merged in

[hai-cea]

Thanks @JAStanton - Fixed with mui/material-ui#1170

New issue to make valueLink work here: #7524