You can write property in your usercontrol
public string DateValue
{
get { return dateValue.Text; }
}
If textbox is holding Date1
above should work or you can change accordingly.
Then just access DateValue wherever you want
In aspx code behind you can create object of user control like below and acces its properties.
UserControl userControl = (UserControl)Page.FindControl("userControl");
Here userControl
is the id for User Control
.