How can I convert this string format 

> 
> 03.07.2019
> 
> 
> 

to the following Date Format?

> 
> 2019-07-03
> 
> 
> 

This is how the String format I get from Soap Services looks like

[![enter image description here](https://i.stack.imgur.com/BhCz1.png)](https://i.stack.imgur.com/BhCz1.png)

```
Public Class ContractBill
Public StartDate As Date
End Class
Dim ctrBill As New ContractBill With {
    .StartDate = Convert.ToDateTime(BillingData.START_DATE.ToString("yyyy-MM-dd"))
}

```

this is my attempt to convert the code to the desired format, but with this .StartDate I get the error:

> 
> System.InvalidCastException: "The object of type" System.String "cannot be converted to type" System.IFormatProvider "."
> 
> 
> 

How can I get this Date format yyyy-MM-dd?